Why Calories Count

You’ve heard calories are important.

You’ve been told for years that weight loss is about calories in versus calories out.

But you’re not happy with that explanation.

If you want to lose weight, you need to eat fewer calories than you expend. Here's why.

If you want to lose weight, you need to eat fewer calories than you expend. Here’s why.
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You’ve heard other people say that calories don’t count — that thermodynamics don’t apply to humans. You’ve heard that weight loss is endlessly complex and that calories are a “scam.”

Both sides say their ideas are supported by scientific evidence and you’re not sure which to believe.

To see which side is right, let’s look at how to set up an experiment to test the idea that calories count when it comes to weight loss. Then we’ll look at the studies that meet these guidelines, the ones that don’t, and what they both show.

How to Conduct a Weight Loss Study

We want to know if eating fewer calories causes weight loss.

Good experimentation is mostly about controlling for confounding variables. In our case, we need to control things that might influence calorie intake and weight loss.

We need some subjects. Since we don’t care about helping rats or mice lose fat — we need humans.

We recruit some slightly overweight or obese people to make the results generalizable to your average person who’s trying to lose weight.

We make sure all of our participants are as similar as possible in terms of weight, health, age, gender, dieting history, etc. This is to make sure these factors don’t distort our results.

After we’ve got our subjects, we begin the experiment.

We need to measure how many calories these people are eating to establish a baseline. We measure their energy expenditure with indirect calorimetry — where the subject’s breath is analyzed for different gases to indicate how many calories they’re burning. This gives us an excellent estimate of their energy expenditure.1,2

To make sure our estimates are correct and adjust their food intake to match their activity levels, we feed them a specific amount of calories for a week or two and monitor their weight. We adjust their calorie intake as needed so they’re eating the same amount they’re burning until they maintain their weight. This is referred to as an “eucaloric diet,” or maintenance.

We prepare all of our subjects’ meals ahead of time. We weigh every gram of food with a digital scale and we watch them during meals to make sure they eat every scrap of food. We also feed all of our subjects the same foods.

We give our subjects instructions to maintain about the same level of activity throughout the study.

Once we find how many calories each of our subjects needs to maintain their weight, we can take our experiment in several directions.

1. To test if eating less causes weight loss…

We would randomly assign half of our subject to a group that eats fewer calories every day. We would assign the other half of our subjects to a group that keeps eating their normal amount of food. If the group that eats less loses weight, then it’s likely that calories count.

2. To test if different macronutrients affect weight loss… 

We would split the subjects into two or more groups, feed them different macronutrient ratios, and put them on the same caloric intake. If one group loses more weight than another, it’s possible that whatever they were eating accelerated (or hindered) their weight loss.

3. To test if different people lose more or less weight on different diets… 

In random order, we would make all of the subjects eat several different diets. We would include a “wash-out” period in between each diet to get a new baseline for each subject. If the subjects consistently lost more weight eating a certain balance of protein, carbs, and fat, it’s possible that a specific macronutrient ratio accelerates weight loss.

This “cross-over” type experiment is also good if you have a small number of subjects (which many weight loss studies do).

4. To test if eating more calories causes weight gain… 

We would make one group eat above their calorie needs, and the other group eat at maintenance. If the former group gained weight, it’s likely that calories count.

These are the main kinds of controlled weight loss experiments you usually see, but there are endless possible variations. We could (and eventually should) also include studies with exercise.

The key is to make sure our subjects do what we tell them.

We want to know for a fact that these people are eating exactly as many calories as we tell them to.

We have to keep them locked in the hospital where we can monitor all of their activity and food intake (no cheating).

We need to keep weighing all of their food and watching them at every meal.

We keep them on these diets for several weeks or months, and measure their weight. If we’re really trying to do a great job, we’d also measure their body composition, energy expenditure, and maybe a few other variables as well.

Like any good study, we’re sure to blind the researchers (us and our colleagues) and the subjects as to who is getting which treatment.

We would need to repeat this study on other people of different weights, genders, ages, and ethnic groups. We would test people with different diseases and different dieting histories (e.g. always been overweight, gained weight recently, etc.). We would also conduct studies that involved exercise and see how it interacts with the diet.

Then we would share our results and wait for other independent researchers across the globe to repeat them — using the same study design.

If other scientists found similar results to our studies, on similar subjects, using the same or similar conditions, we could assume with a reasonable level of certainty that our findings were correct. Then we’d throw a crazy party and blow a bunch of funding money (kidding).

If our findings were repeated consistently for years — even decades — and we were able to logically explain any odd results, we could call our theory a fact (an idea with the highest level of certainty).

Weight loss researchers have done exactly this (except for the parties) for over a century. Let’s see what they’ve found.

When People Create a Caloric Deficit — They Always Lose Weight

Studies using the rigorous standards outlined above have consistently shown that when people eat a calorie restricted diet — they lose weight.3-6

That is, when researchers measure people’s energy expenditure, weigh all of their food and count their calorie intake, and force them to eat less food than they need to maintain their weight — they lose weight. The amount of weight they lose is also generally proportional to the size of their caloric deficit.

Whether they eat mostly protein, fat, or carbs makes no significant difference in how much weight they lose.3,5,7-9 Eating more protein does cause you to burn slightly more calories, around 70-100 per day, but it’s usually not enough to make a significant difference in weight loss.10-13

At this point, eating a calorie restricted diet and exercising (largely to burn more calories) are also considered the two most scientifically supported ways to lose weight.14-17 It works.

When you restrict your calorie intake enough to create a deficit, you lose weight. It turns out the reverse is also true.

When People Eat More Calories than They Need — They Always Gain Weight

In studies where subjects are forced to overeat — they always gain weight.18-24 25-28

There is often a lot of individual variation in how much weight and fat people gain, but they always gain some. These differences are mostly because some people subconsciously move more when they overeat to burn off the extra calories (a phenomenon called non-exercise activity thermogenesis, or “NEAT,” which we’ll talk about later).19,24,29-32

However, this increase in subconscious energy expenditure is never enough to completely offset the increase in calories. In every study thus far — people still gain weight when they are eating more calories than they expend. They never expend enough to completely prevent weight gain when they overeat calories.

On the other hand, not all studies seem to show that eating fewer calories is necessary for weight loss, or that eating more calories causes weight gain.

Why Some Studies Seem to Show that Calories Don’t Count

As usual, people claim that you can find a study to prove anything. You can’t, but here’s why people think that’s true when it comes to calories and weight loss.

Studies often report that people eating low-carb diets lose as much or more weight as those eating high-carb diets, sometimes despite the subjects claiming to eat the same or more calories.33-45

There are also a similar number of these studies that have found greater or no difference in weight loss between high- and low-carb diets, but like most people who claim calories don’t count, we’re going to ignore those for now (and come back to them in a minute).46-62

Based on these studies people claim that:

1. You can lose weight without a caloric deficit.

2. You can lose more weight on the same calorie deficit by avoiding certain foods or macronutrients, like carbs. Thus macronutrients are what you should focus on — not calories.

Both of these claims are completely untrue.

None of these studies controlled for the variables we talked about at the beginning of this article. Most of these studies were conducted under “free-living conditions,” which means the subjects were given instructions on what to eat, sent home, and told to track their food intake.

They chose what — and how much — to eat and the researchers had to trust their diet records.

This is a big problem.

Diets Help People Eat Less Without Realizing It

When people go on a diet, they tend to spontaneously eat less for several reasons.

First, diets place restrictions on what and when you can eat.

  • No carbs.
  • Low-fat.
  • No meat.
  • No gluten.
  • No grains, dairy, or legumes.
  • No eating late at night.
  • Eat every three hours.
  • Don’t eat breakfast.
  • Intermittently fast.
  • No processed foods.
  • No sweets.
  • No sugar.

When you take away a signifiant portion of someone’s diet or place limits on when they can eat, they can’t help but eat less (at least for a while). If someone’s used to getting 50% of their calories from carbs — and they cut that to less than 10% — they’re going to eat less until they get used to their new diet.

Placing a limit on food variety also tends to make people eat less without realizing it. If you have fewer food options, you get bored faster and tend to eat less.63 When people have more options, they eat more.63,64

Perhaps the biggest reason people eating low-carb diets sometimes lose more weight is that they also tend to eat more protein. Studies have repeatedly found that when people eat more protein, they feel fuller and spontaneously eat fewer calories without knowing it.65-70

When people switch to a high protein low-carb diet, they sometimes spontaneously reduce their food intake by 1,000 calories per day.71 These people didn’t notice the difference, yet in just two weeks they lost 3.6 pounds (1.65 kilograms).

You’d think people would notice if they were eating significantly fewer calories. They don’t.

People Have No Clue How Much they Eat

People are horrible at estimating their calorie intake.72-101 102-120

Overweight and obese people (especially women) are often the worst, but most people underestimate their calorie intake to some degree.

It’s true for men and women and people of all ages.

It’s true when people are given specific instructions on how to measure their food intake.

It’s true for dietitians.102

It’s true even when people are paid to track their food intake.104

In some cases, people who claim they can’t lose weight by cutting calories underestimate their food intake by 47%, and overestimate their exercise levels by 51%.75 Other data has shown that people can underreport their food intake by up to 2,000 calories per day.89

It’s likely that the people on high carb diets are more likely to underreport their food intake. This would make it seem as if people on low-carb diets are losing weight despite eating more calories.

The people on high carb diets in weight loss studies are often told to consciously restrict their calorie intake and avoid “unhealthy” or “bad” foods, especially fat. These are all behaviors that generally increase the likelihood that people will underreport their food intake.81,92,97-101,121

On the other hand, the people eating the low-carb diets are often told to eat as much fat and protein as they want.

Remember that most of these people were probably making some attempt to control fat intake before the study, or were at least used to the idea that fat is “bad” (thanks largely to the USDA, FDA, and other health agencies). When they’re told to eat a low-carb high-fat diet and to eat as much of these previously “forbidden” foods as they want, even small amounts can feel like a lot of food.

People on low-carb diets often eat more total protein and fat, which helps blunt their appetite.65-70,122 In contrast, the people in the high-carb groups in these studies are often eating lots of refined carbs which tend to be far less filling. In fact, studies have shown that it’s actually the high protein content of the diet that helps control appetite and cause weight loss, not the avoidance of carbs.123

Enjoying previously taboo foods, eating more protein and fat, and not being told to restrict calories drives people in the low-carb groups to eat less and report they’re eating more than they really are.

This effect wears off, however. These people generally get used to their new diet and start eating more of the low-carb high-fat foods —  and thus total calories. Over time they also tend to get bored with their diet and become less compliant.

This is why most free-living studies lasting longer than six months have found that people on high- or low-carb diets lose the same amount of weight.33,43,45,62,124,125 It’s probably also why many free-living studies have found that people lose the same amount of weight eating high- or low-carb diets.

This is why you should be highly skeptical of people who claim they lost weight without eating fewer calories. Calories count. These people are just not counting them accurately, if at all.

If eating a low-carb diet helps you lose weight without counting calories — that’s great — as long as you can maintain it or find another option if it stops working. However, that doesn’t mean calories don’t count or that low-carb is the ONE TRUE DIET™ that will work for everyone.

The people who lost more weight in these free-living studies were eating fewer calories — they just didn’t know it.

Low-Carb Diets Make People Lose More Water Weight

There are several controlled studies that have found people eating low-carb diets lost more weight than those on high-carb diets.126-129 Unfortunately, these studies have other problems.

While the people on low-carb diets lost more weight, they didn’t lose more fat — they lost water weight.128,130

When you eat carbs, they’re largely converted into muscle glycogen — the storage form of carbohydrate. Every gram of glycogen is bound to about 3-4 grams of water.131,132

When you switch to a low-carb diet, your glycogen levels drop, and you lose water weight.133-136 Low-carb diets also tend to deplete electrolyte levels which can also have a diuretic (water depleting) effect.

Several of the studies that found low-carb diets helped people lose more weight only measured total body weight. They didn’t measure body composition, so there’s no way to know whether they lost fat, water, or muscle.

Other studies have measured or controlled for changes in water weight and have found no difference in fat loss.

Granted, it’s fun to see big changes in scale weight when you slash carbs, but those aren’t necessarily big changes in fat loss.

You Are Not a Rodent

Rodents also only lose weight when they’re in a caloric deficit, but there is at least one rodent study that found a ketogenic diet (generally less than 100 grams of carbs per day in humans) increased metabolic rate and weight loss more than a high-carb diet.137

However, there are several reasons these results are far less important than they appear at first sight.

First of all, there are other studies showing that rats overfed on a ketogenic diet still gain significant amounts of fat — more so than on high-carb diets.138 In another mouse study where a ketogenic diet also increased energy expenditure and prevented weight gain, it still caused insulin resistance.139

Other studies have also found that rats placed on a low-carb diet don’t lose weight unless they also eat fewer calories.140

However, none of these animal studies show how a specific diet will help you lose weight. Rats are not humans, and studies on rats, mice, and other animals can never be completely generalized to people.

Rodents have several different physiological traits that may make it easier for them to gain fat on high-carb diets.141-143 They convert carbohydrate to fat (a process called “de novo lipogenesis”) about 10 times more efficiently than humans do.144,145 This is true for other animals like pigs as well.146 Rodents also process protein and fat differently.147,148

It’s fine to make educated guesses based on rodent studies of how something might work in humans. However, those results have to be validated by controlled human studies before you can call them anything more than “interesting.”

If we later find that the same diet that caused fat loss in rats didn’t work for humans, and this holds true for multiple studies, then it doesn’t work for humans — period. That’s exactly what we’ve found with low-carb diets and weight loss.

How to lose weight is one of the most thoroughly researched questions in the past 100 years, and at this point we have enough good human trials to stop worrying about rat studies. Not that they don’t have some value, but they don’t meet the same standard of evidence that human studies do.

Calories Count

Now you know why calories count.

Using rigorously controlled studies, we’ve found that:

1. When people are in a caloric deficit, they always lose weight.

2. When people are in a caloric surplus, they always gain weight.

3. You also learned that when people are allowed to decide how much they eat — under poorly controlled conditions — they sometimes lose more weight on low-carb diets without realizing it. Some people claim this is proof that calories don’t matter, when all it really proves is that people are bad at measuring their calorie intake. It also proves that high protein diets can help people lose weight by eating fewer calories.

4. Low-carb diets make people lose water weight, which often gives the impression that they’re losing more fat at the same calorie intake as people on high-carb diets.

5. It’s impossible to generalize weight loss studies on rats and mice to humans, as we have vastly different metabolisms. You are not a rodent, and what helps a rat lose weight may not do the same for you.

So you know calories count. But you’re not convinced all calories are created equal or that it’s really possible to manage them. Maybe low-carb diets aren’t magical, but on a practical level — isn’t there more to weight loss than calories in versus calories out?

In the next few articles, we’ll look at whether or not a calorie is a calorie, and whether or not it’s possible to actually control your energy intake and expenditure to lose weight.

If you enjoyed this article, please share it on Facebook.

 

Disclosures: None.

Special thanks to Alan Aragon and Anthony Colpo for their excellent research in this area, sharing that research, and taking so much crap for it.

 

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Comments

  1. says

    Good stuff, Armi.

    Will future articles address whether it’s possible to gain muscle while maintaining a caloric deficit (and thus, simultaneously lose fat)?

      • Rob says

        I’m also VERY interested in this idea. People always say you can’t build muscle unless you eat at a caloric surplus and you can’t build muscle and lose fat at the same time. However, if macro nutrient ratios work the way they say they do in building muscle, one should be able to keep calories at maintenance and ‘switch out’ fat for muscle by maintaining the right macro-nutrient proportions while doing adequate strength/hypertrophy training.

        Currently I’m 5’11″, 162lbs and probably around 20% bodyfat (if not a little more). I’d be pretty happy to be the same weight but 10% or less bodyfat. I wouldn’t be “huge” but I’d be reasonably cut and have a nice physique. I’d probably want to gain more muscle from there but it’d be a good starting goal.

        • says

          Hey Rob, there’s some truth to both sides. I’ll address this issue in future articles. In the mean time, are you currently strength training? Do you know your calories and macros?

      • says

        I am interested in reading your article on this. Everything I have read has been to the contrary. How does one maintain a mass loss state while increasing muscle mass?

    • William Mandell says

      The simple answer is, YES, it is possible to ‘gain muscle’ while eating a caloric deficit. You have seen thousands of real life cases already where people ‘lost bodyfat’ (meaning they HAD TO eat a caloric deficit), but became more muscular. If you personally have never witnessed this, then you have not been to a military basic training program where this is the rule for practically everyone there, not the exception. Ill be writing an article on this shortly.

  2. says

    Interesting article Armi. While I knew the ultimate conclusion, I enjoyed following the logic that get’s me there. Looking forward to your next few articles about controlling energy intake and its affects.

    One point I would add has to do with the comment that, “The amount of weight they lose is also generally proportional to the size of their caloric deficit.” While I know that the comment says “generally”, which is true, I think it should be added that it is true “up to a point”. There is a point at which dropping too many calories no longer has the intended benefit. I know that this is perhaps outside the scope of this particular article, but I think still a worthwhile point.

    Good article!

    • says

      Thanks Kevin,

      That’s a good point, but the article was getting pretty long as it was. I definitely plan on addressing the issue of too massive of a caloric deficit, especially combined with tons of exercise.

      - Armi

  3. Etienne Chambord says

    This by far the most comprehensive and well-rounded concise article regarding energy balance and body composition. Well done !

  4. Barbara says

    Of course it’s true that weight loss is about calories in and calories out. This truth has limited usefulness as an INSTRUCTION.

    I get the points: “Just because you exercise doesn’t mean you can eat anything you want.” “If you’re exercising but still gaining weight or not losing weight, you’re eating too many calories, and switching around macronutrients won’t change that.”

    But “calories in, calories out” is a snarky and unhelpful way to deliver those points. Both calories in and calories out for most people are estimates based on weight itself. People aren’t measuring their basal metabolism or the oxygen consumption rate during exercise. They are looking at the scale and keeping track of whether they go up or down and adjusting their food and exercise accordingly (or not). And the fact is, changing macronutrient consumption can change calorie intake in a number of ways: a person might eat lower-fat versions of the same food to reduce overall calories; he might simply reduce the foods he overeats habitually, e.g., “cut out carbs” ultimately means no more cookies and pie; he may reduce portion sizes because one small juicy steak is as satisfying as a giant veggie burrito.

    • says

      Of course it’s true that weight loss is about calories in and calories out. This truth has limited usefulness as an INSTRUCTION.

      “Of course” implies everyone understands calories count. Many people do not, hence the writing of this article.

      Actually, it’s not only useful, but essential for laying the ground work of any fat loss plan. Until people do understand calories count, they usually end up wasting their time on stuff that doesn’t work.

      But “calories in, calories out” is a snarky and unhelpful way to deliver those points.

      How would you put it?

      Both calories in and calories out for most people are estimates based on weight itself. People aren’t measuring their basal metabolism or the oxygen consumption rate during exercise. They are looking at the scale and keeping track of whether they go up or down and adjusting their food and exercise accordingly (or not).

      They don’t need to get an exact number. All they have to understand is their relative calorie intake, and adjust from there. How does this not jive with calories in vs calories out?

      And the fact is, changing macronutrient consumption can change calorie intake in a number of ways: a person might eat lower-fat versions of the same food to reduce overall calories; he might simply reduce the foods he overeats habitually, e.g., “cut out carbs” ultimately means no more cookies and pie; he may reduce portion sizes because one small juicy steak is as satisfying as a giant veggie burrito.

      I agree. Did you read the words under the headline that says: “Diets Help People Eat Less Without Realizing It” ?

  5. Brian says

    Thanks for sharing but I can’t say I fully agree with your article or the way you’ve presented the research.

    In a vacuum the idea of calories in vs. calories out works, but in real life it just isn’t extremely applicable or sustainable and for many reasons:

    1) calorie counts can be off by as much as 20-30%. How do we adjust for this in real life?
    2) some individuals actually GAIN weight on so called caloric restrictive diets. There are other factors at play that can affect this (thyroid function, other hormones like insulin, and the bodys use of stored energy)
    3) based on the above statement, we are not static state beings, so our caloric intake should naturally vary day by day based on activity level or other stressors.

    I would recommend looking at the research of biochemist Stephan Guyenet at Whole Health Source.

    • Jason Ross says

      Brian,

      In the long-term studies mentioned above the factors you raised in point 2 are controlled for.

    • says

      1) calorie counts can be off by as much as 20-30%. How do we adjust for this in real life?

      You make adjustments to your food intake and activity levels based on your rate of weight loss or weight gain. You don’t need to be exact — it’s about relative changes.

      2) some individuals actually GAIN weight on so called caloric restrictive diets. There are other factors at play that can affect this (thyroid function, other hormones like insulin, and the bodys use of stored energy)

      Please provide some references.

      3) based on the above statement, we are not static state beings, so our caloric intake should naturally vary day by day based on activity level or other stressors.

      I never said it doesn’t change. I also didn’t say you needed to eat exactly a certain amount of calories per day to lose weight. It’s about long-term changes in energy balance, not within a 24-hour time span.

      I have read Stephan Guyenet’s work — it’s excellent. That’s why I linked to him in this article.

  6. Jason Ross says

    Armi,

    That’s a fairly serious amount of work for a blog entry, 148 references!

    It’s nice to see a well-referenced scientific review instead of the usual opinionated bandwagon pushing in the diet/nutrition space.

    Cheers.

  7. Kierstin says

    This article presents 2 choices: ‘calories are important’ and ‘calories are not important’. This is a straw figure argument. The positions presented do not reflect the positions accurately. This is a better list of positions:

    1. Caloric intake is the only issue that matters for weight loss.
    2. Caloric intake is one of many issues that matter for weight loss.
    3. Caloric intake is irrelevant to weight loss.

    Really, when you read the published data on this (and is anyone really arguing that we should use crap studies? No, they’re not), then the only scientifically supportable answer on this list is #2.

    That’s right. The Paleo folks, the calorie-restriction folks, the Raw food folks, the vegans, the fat-restriction folks, (or at least the sub-set of these groups which pay attention to published research) are all really coming to the same conclusion here. Calories matter, but what really matters is a whole host of complex factors that contribute to issues relating to obesity, satiety, activity, health status, etc. In fact, this article does a good job in listing many of these factors which contribute to the complex of weight loss.

    So it’s not a matter of ‘do calories matter at all’? That is not a debatable research-based question. Clearly they do. If that is the sole point of the post, then clearly it is supported.

    But focusing on caloric intake alone for weight loss is not a research-supported approach. And in fact, weight loss without broader engagement to questions of health is flagrantly irresponsible. Therefore, consideration of caloric intake for the purposes of weight loss must also be engaged in complexly. How much do calories matter? For whom? In what circumstances and contexts? With what objectives? In what combinations of other factors? Really, these are among the questions that need to be considered.

    Anybody that takes their health seriously, as an individual or as a clinical professional must take these complexities beyond ‘caloric intake’ into consideration. Obesity and health are holistic and therefore any clinical approach which is overly reductionistic should be considered irresponsible, non-scientific, and potentially dangerous.

    • says

      Hi Kierstin, thanks for commenting.

      This article presents 2 choices: ‘calories are important’ and ‘calories are not important’. This is a straw figure argument. The positions presented do not reflect the positions accurately.

      I never said that in the entire article. Who’s making the straw man?

      1. Caloric intake is the only issue that matters for weight loss.
      2. Caloric intake is one of many issues that matter for weight loss.
      3. Caloric intake is irrelevant to weight loss.

      Really, when you read the published data on this (and is anyone really arguing that we should use crap studies? No, they’re not), then the only scientifically supportable answer on this list is #2.

      There are many people who do rely on “crap studies” to support their ideas. It’s actually quite common. I agree with your second statement that calorie intake is on of many factors that matter for weight loss. However, nothing else is going to help people lose weight unless it also supports the maintenance of a caloric deficit over time.

      Calories matter, but what really matters is a whole host of complex factors that contribute to issues relating to obesity, satiety, activity, health status, etc. In fact, this article does a good job in listing many of these factors which contribute to the complex of weight loss.

      Again, I agree, but every discussion about weight loss has to start with calories. I’m going to continue this discussion in future articles, and will address the issues you mentioned.

      So it’s not a matter of ‘do calories matter at all’? That is not a debatable research-based question. Clearly they do. If that is the sole point of the post, then clearly it is supported.

      Every question is debatable, some just don’t last very long. The sole point of this post was to show that calories matter, so thank you.

      But focusing on caloric intake alone for weight loss is not a research-supported approach. And in fact, weight loss without broader engagement to questions of health is flagrantly irresponsible. Therefore, consideration of caloric intake for the purposes of weight loss must also be engaged in complexly. How much do calories matter? For whom? In what circumstances and contexts? With what objectives? In what combinations of other factors? Really, these are among the questions that need to be considered.

      Actually it is, just in the short-term. It doesn’t matter how healthy or unhealthy someone is or what they eat, if they create a caloric deficit, they lose weight. If you want someone to stick with the diet in the long-term, then yes, other factors matter as well. I also agree that some people may need to address health issues before pursuing weight loss. For others, weight loss is their biggest health issue.

      If someone’s goal is to lose weight, calories always matter. A lot.

      Anybody that takes their health seriously, as an individual or as a clinical professional must take these complexities beyond ‘caloric intake’ into consideration. Obesity and health are holistic and therefore any clinical approach which is overly reductionistic should be considered irresponsible, non-scientific, and potentially dangerous.

      I agree that calorie intake is not the sole determinant of health. However, reductionism is still an essential component of science.

      Thanks again for the comment. I think we agree on more than we disagree.

      - Armi

  8. Matias Page says

    Thanks for this great article.
    I have one comment and I’d like to point out that I know nothing. I merely read a lot about science.

    You write in this paragraph:
    “If our findings were repeated consistently for years — even decades — and we were able to logically explain any odd results, we could call our theory a fact (an idea with the highest level of certainty).”

    …I thought that in science, theories don’t get promoted to facts. Facts are explained by theories… I’m using this simple definition of the word theory by Qualia Soup as a starting point: A well-substantiated explanation accounting for a body of well-substantiated facts.

    So my question is what do you mean by that paragraph? Do you think that after a while a theory becomes a fact?

    By the way English is not my native language.

    Cheers!

    • says

      Thanks Matias,

      You’r sort of right. Any good theory is rooted in at least indirect factual evidence. I don’t mean that if a theory sticks around long enough, i.e. people keep repeating it, then it’s a fact. What I mean is that if a group of people get together, form a valid hypothesis based on their current knowledge, and then repeatedly test their hypothesis/theory, then it does become a fact — if the research supports it.

      Here’s how that works for weight loss (in a simplified form):

      1. Researchers know that humans obtain energy from food.
      2. People who don’t eat enough starve to death.
      3. People who eat a lot usually get fat.
      4. Based on points 1-3, the researchers form a theory that the energy we get from food dictates our body weight, and that changing the amount of available energy from food will also change body weight in proportion to the gain or loss of calories (food energy).
      5. The researchers decide to test this theory with objective methods (the studies listed in this article). Over time, under all sorts of different situations, their theory proves true.
      6. Calories count.

      Does that make sense?

      Thanks again for the excellent question,

      - Armi

  9. says

    Great post Armi. I think you affectively answered this in many ways in the post, but does the type of calories matter in gaining weight? Like if a person is eating too many calories, will more calories form carbs or fat or protein cause them to gain weight more quickly or predispose them to it? Just curious as to sort of the inverse of what you some thoroughly outlined in this article!

    Thanks

    • says

      Chuck, if you are a healthy and physically active individual following a macro-nutrient split that has any semblance of sanity (that is providing sufficient amounts of protein to promote LBM synthesis and fats to keep hormones ‘happy’) there should be no problem at all allocating the rest of your calories to carbs.

    • says

      Thanks Chuck,

      In short, sort-of — under certain conditions. Carbohydrate overfeeding generally results in less fat gain than does fat overfeeding.(1) But we’re talking about massive amounts of calories, and both groups still gained a lot of fat. So for short-term overfeeding, e.g. a refeed, then the quality of calories does matter to a certain extent. This is also because of carbohydrate’s effect on leptin levels. But the effects are still small and not all studies have even found significant differences.

      I’ll go more into depth on this in later articles.

      Glad to hear from you again buddy. :)

      1. Horton TJ, Drougas H, Brachey A, Reed GW, Peters JC, Hill JO. Fat and carbohydrate overfeeding in humans: different effects on energy storage. Am J Clin Nutr. 1995;62(1):19–29. Available at: http://ajcn.nutrition.org/content/62/1/19.long.

    • says

      I think it’s important to discern whether we’re talking about healthy individuals, or folks with a host of metabolic issues, diabetes included. In healthy individuals, taking an approach that puts calories in the forefront is an easy and practical way to achieve fat loss/weight gain.

      Obviously, in individuals who have a host of metabolic issues, this approach would be reductionist and it would ignore the myriad of other factors that come into play.

      So all recommendations depend on the context of the situation.

      Jake

      • says

        Jake, I agree. But whether or not someone is metabolically healthy does not change the fact they if they want to lose weight, they have to create a caloric deficit.

        Whether or not you prioritize weight loss over other health issues obviously depends on the individual. It’s worth noting that one of the best ways to reduce symptoms of metabolic syndrome is through weight loss, however.

    • says

      Peter Attia is a militantly anti-carb guy, from what I’ve read. If Attia – who seems to be really smart – claims to go wherever the science takes him, then he should consider that the current evidence does not consistently support the supremacy of low-carb dieting for treating type 2 diabetes. In fact, in a recent systematic review & meta-analysis, the diet that performed best for weight loss and glycemic control (although not to a statistically significant degree) was the Mediterranean model (up to 55% of total kcal from carbohydrate), not the low-carb (20-60 g/day) model. And keep in mind the vast majority of subjects in the studies were overweight & obese. To quote the authors:

      “Dietary behaviors and choices are often personal, and it is usually more realistic for a dietary modification to be individualized rather than to use a one-size-fits-all approach for each person. The diets reviewed in this study show that there may be a range of beneficial dietary options for people with T2D.”
      http://www.ncbi.nlm.nih.gov/pubmed/23364002

      And once again, flexibility & moderation win. Not too shocking.

  10. Clifton says

    Questions for ya.
    1. in your research, did you come across any information that would speak to the level of slowing of metabolic rate when in a calorie restricted diet? related: http://suppversity.blogspot.com/2013/07/do-chronic-energy-deficits-make.html
    2. relating to #1, refeeds as a tool to revamp/reup metabolic processes…
    3. I believe in the comments you alluded to discussing simultaneous lean gains with fat loss….it’s true the calorie measure works for weight loss, do you think fat loss is more valuable of a goal? Where the higher (not high) protein intakes protect against muscle loss during weight loss.
    4. that’s it for now

    • says

      Thanks for the comment Clifton,

      1. in your research, did you come across any information that would speak to the level of slowing of metabolic rate when in a calorie restricted diet? related: http://suppversity.blogspot.com/2013/07/do-chronic-energy-deficits-make.html

      Yes. See my response to Mitchell here: http://evidencemag.com/why-calories-count/#comment-8206

      2. relating to #1, refeeds as a tool to revamp/reup metabolic processes…

      Useful under certain circumstances, but most of the claims being made about their effects are wildly exaggerated.

      3. I believe in the comments you alluded to discussing simultaneous lean gains with fat loss….it’s true the calorie measure works for weight loss, do you think fat loss is more valuable of a goal? Where the higher (not high) protein intakes protect against muscle loss during weight loss.

      Under certain conditions — yes. I think it’s possible to lose fat and gain muscle at the same time. For most, it’s more a matter of minimizing fat gain while increasing muscle mass. I’ll (obsessively) discuss more about how to enhance body composition in later articles. And yes, protein intake makes a huge difference in the amount of fat lost while dieting.

  11. Mitchell says

    I must say that the premise of this article made me weary since calorie deficit diets are effective temporarily at making people lose weight.
    The problem is that its temporary and leaves adverse lasting impact on one’s health and metabolism. I disagree with counting calories, but instead support eating healthier.
    If it gets people to do that, then i guess i can support it.

    http://tomnikkola.com/9-reasons-why-counting-calories-is-dumb/

    • says

      Hi Mitchell,

      You’re first point is correct, although also irrelevant. The drop in metabolic rate during weight loss is almost entirely from a decrease in movement — mostly just daily activities. The rest of the decrease is because people are losing weight, so they’re burning fewer calories to move their bodies. In some cases there is a small drop in metabolic rate, but this is generally minor. Some studies haven’t even found it to exist (usually in people with more weight to lose in the first place).

      Are you saying that a calorie restricted diet is necessary for weight loss, but metabolic slowdown only occurs if you eat certain “healthy” foods?

  12. says

    I don’t believe that “calories don’t count” nor do I believe that low carb diets are the ONE TRUE DIET (I don’t believe there is any such thing), but you neglected a study by Volek and Phinney that addresses many of the points you raise, and STILL shows that people eating about the same amount of calories who reduced carbs rather than fat lost more weight. 1) There was no explicit calorie restriction in either arm 2) if there was reporting error, it would be randomized; both groups could be expected to over/underreport to the same extent 3) protein intake was higher in the LC arm, by an average of an ounce/day, if that’s your idea of “higher” protein intake; both groups seemed to be eating adequate protein 4) body composition was measured; most “weight loss” came from abdominal fat. (Volek, Phinney, Forsythe, et al. 2009)

    I’m not saying this one study completely proves anything, but it is compelling. I appreciate your efforts to try to clarify matters, but it isn’t a black and white situation. For you, perhaps quantity of calories is more important than quality, but that does not necessarily apply to everyone. For others, while calories do count, the quality of the calories eaten is more important to health than the quantity.

    • says

      Adele,

      Just to be clear, you’re saying that total calories are not important as the composition of those calories, and as support, you’re citing results that were based on total caloric intake (which can’t be confirmed, since intake was self-regulated over 75% of study duration.)

      Anyway, the difference in body mass between the two groups after 12 weeks (short duration) was just under 11 pounds. Considering how much glycogen can be stored in liver and muscle, and how much water is stored along with it, an 11 pound difference is neither surprising nor impressive. It’s also interesting to note that the reported change in BF% for both groups was essentially the same.

      Your last point is a strawman. Food quality wasn’t the issue in this post and there was nothing to indicate that the author disregards health or quality of food intake. Whether the goal is weight loss, weight gain, or maintenance, the first law of thermodynamics does in fact apply to everyone.

      • says

        The results of the Volek/Phinney study are reported both in terms of total calories and macronutrient content (grams and percentages, hooray!). Not sure what the problem is here, since we are talking about both issues. And, I’ll type this very slowly for you, the whole idea of an RCT is that error (as in misreporting) is also randomized. That’s the point. Did anybody misreport intake? We don’t know; we *never* know. But this is what makes an RCT a better tool for examining intake compared to an observational study. Does the intervention itself create systematic bias w/r/t reporting in one group vs. another, with a LC arm of a trial always overreporting and the LF arm always underreporting, making it look like they consumed the same amount of calories when they really didn’t? Possibly, but this takes you into a realm of speculation unbecoming to someone who is relying on science to prove a point, so you’d have to find some studies that indicate that this may be the case.

        Not trying to impress or surprise you—in fact, I would be surprised if you were impressed (although I wouldn’t be impressed if you were surprised). Yup, it is interesting that overall BF is essentially the same for both groups.

        Depends. If food quality =macronutrient content, which sometimes it does and sometimes it doesn’t, then yes, food quality is the issue at hand. Both groups seem to have nutritionally adequate diets as far as I could determine, so perhaps “quality” is not the best word. How about instead of “quantity vs. quality” I rephrase that: “quantity of food energy assumed to be released by breaking down the molecular bonds of the designated food molecules consumed under conditions where those molecules would be transformed directly from their present state into ATP within the body vs. type of molecule found in food that may play a structural and/or functional role in the complex biological system that is the human body, in addition to acting as a possible source of ATP.”

        Researchers generally must exclude participants who routinely go about flouting the laws of physics as we know them, so yes, it would still apply in this study.

        I have a much less exciting way of thinking about it. Different food molecules play different roles in both metabolic structure and signaling processes. How do you “count” the calories in a group of amino acids (from a protein molecule ostensibly “worth” 4 calories) when they are used for creating something in the body that wasn’t there before (an enzyme, a bone cell, a hormone)? They are being “conserved” as in accordance with the first law, but they are not being “stored” or utilized for energy needs—oh, and sometimes they get mangled along the way and can’t be used at all (a little H pops off and rolls under the couch where you can’t get it, that sort of thing). What if it takes more “calories” to digest, dismantle and reassemble into something else one type of food “calorie” compared to another? What if one kind of “calorie” sets off a chain reaction that upregulates the transcription of enzymes that makes it easier for the body to store fat (as in the stimulation of the production of xylulose-5-phosphate through the pentose phosphate pathway resulting in the activation of ChREBP)? Nope, just the calories, ma’am?

        I don’t know you and the internet is a strange place, so I may be wrong about this—but you are *probably* not a bomb calorimeter. And if you are, I’m pleased to make your acquaintance, and you can skip the rest of my reply, since it doesn’t apply to you.

        I’ll let Feinman and Fine explain it: “The idea that “a calorie is a calorie” comes from a misunderstanding of the laws of thermodynamics. There are two laws of thermodynamics. When speaking of “the laws of thermodynamics” it is important to be sure that one is including the second law. The first law is very different in character from the second law. The first law is a conservation law: it says that the form of energy may change, but the total is always conserved. The second law is a dissipation law: it defines a quantity, the entropy, S, which we traditionally identify with disorder or high probability. The second law says that in any (real) irreversible process, the entropy must increase (ΔS > 0); balance is not expected. Entropy is, in fact, identifiable with irreversibility.”

        The first law of thermodynamics always applies (hello? that’s what makes it a *law*), but it is the second law that drives chemical reactions, and that’s what we are talking about here—chemical reactions that occur in the body as you digest, absorb, assimilate, and utilize the components of the food that we eat. We are generally not 100% efficient machines. (Although maybe you are, and how awesome is that for you?)

        Feinman and Fine again: “The second law was developed in the context of the industrial revolution and the attempt to understand the efficiency of machines. The law describes the theoretical limits on the efficiency of engines and applies as well to living (irreversible) systems. The second law says that no machine is completely efficient. Some of the available energy is lost as heat and in the internal rearrangement of chemical compounds and other changes in entropy. In other words, although the first law holds even in irreversible processes – energy is still conserved – the second law says that something is lost, something is unrecoverable. The efficiency of a machine is dependent on how the machine works and, for a biochemical machine, the nature of the fuel and the processes enlisted by the organism. A simple example is the inefficiency of low-test gasoline in high compression gasoline engines. If a “calorie is a calorie” were true, nobody would pay extra for high test gasoline. (The calorimeter values of a gasoline will be the same whether or not it contains an antiknock compound). In weight loss diets, of course, inefficiency is desirable and is tied to hormonal levels and enzyme activities.”

        Hormonal levels and enzyme activity can be affected by the *type* of food molecules you consume or even the type of food molecules that your mother consumed, not just sheer amount. Crazy, huh?

        Do you have to consume more calories than you utilize in order to gain weight? Do you have to utilize more calories than you consume in order to lose weight? Yes, in terms of first law energetics—but this tells us exactly nothing. In terms of the system as a whole (not that this applies to you Mr. Bomb Calorimeter), what is it that determines when (and how much) energy is utilized, remembering that stored energy must be mobilized before it can be utilized? Various enzymatic and hormonal milieus can facilitate those processes, one of which can be created, by some people, by consciously restricting the quantity of food energy assumed to be released by breaking down the molecular bonds of the designated food molecules consumed under conditions where those molecules would be transformed directly from their present state into ATP within the body, relative to previous intake. For other people, manipulating the type of molecule found in food elicits a structural and/or functional role of the said molecules in the complex biological system that is the human body, in addition to acting as a possible source of ATP, which allows an enzymatic and/or hormonal milieu that facilitates the mobilization and utilization of stored energy.

        Not sure why this is so offensive to some. I’m just saying, it’s complicated.

        • says

          If someone makes reference to a “first” law, then they must be aware that at least one other law exists, right? Yes, it costs energy to digest and metabolize food, etc…

          How much does the metabolic cost of digestion/transport/anabolism/catabolism of each substrate really change with respect to caloric intake? You seem to be saying that it does, so please quantify that. And does “the complex biological system that is the human body”, as you put it, have any potential for adaptation in response to changes in diet or activity?

          Let’s assume that a low-carb diet is metabolically less efficient than a high-carb diet (sure, let’s ignore protein LOL), which allows you to consume the same amount of calories while creating a negative energy balance… first of all, how could you ever know that without counting calories and somehow measuring expenditure?

          And how do you know that our complex biological systems will never downregulate spontaneous levels of daily activity to compensate? Without acknowledging that possibility, your own argument (or really, Feinman’s) actually invokes a very strict definition of “calories in, calories out”.

          What determines whether an ingested food compound is added to what is already available for use in structure or function (increasing body mass), as opposed to being utilized for energy production? Does caloric surplus or deficit have anything at all to do with that? And stored body mass, whether lean or lipid, is not available as an energy source in times of deficit?

          In the Volek, Phinney study you cited, we have two diet categories: low-carb and low-fat. Both resulted in very similar changes in body mass (when adjusted for water loss, which the authors as well as yourself have conveniently ignored) and composition, and both at a very similarly reported caloric deficit…

          It should be obvious that you need to create a caloric deficit to lose weight, regardless of the diet plan being followed. But to quote Robert Sapolsky: “When you think in categories, you overestimate how different [two facts] are when there happens to be a boundary between them.”

        • says

          the whole idea of an RCT is that error (as in misreporting) is also randomized. That’s the point. Did anybody misreport intake? We don’t know; we *never* know. But this is what makes an RCT a better tool for examining intake compared to an observational study. Does the intervention itself create systematic bias w/r/t reporting in one group vs. another, with a LC arm of a trial always overreporting and the LF arm always underreporting, making it look like they consumed the same amount of calories when they really didn’t?

          The article already addressed the claim that misreporting would be randomized between both groups here:

          It’s likely that the people on high carb diets are more likely to underreport their food intake. This would make it seem as if people on low-carb diets are losing weight despite eating more calories.

          The people on high carb diets in weight loss studies are often told to consciously restrict their calorie intake and avoid “unhealthy” or “bad” foods, especially fat. These are all behaviors that generally increase the likelihood that people will underreport their food intake.81,92,97-101,121

          On the other hand, the people eating the low-carb diets are often told to eat as much fat and protein as they want.

          Remember that most of these people were probably making some attempt to control fat intake before the study, or were at least used to the idea that fat is “bad” (thanks largely to the USDA, FDA, and other health agencies). When they’re told to eat a low-carb high-fat diet and to eat as much of these previously “forbidden” foods as they want, even small amounts can feel like a lot of food.

          People on low-carb diets often eat more total protein and fat, which helps blunt their appetite.65-70,122 In contrast, the people in the high-carb groups in these studies are often eating lots of refined carbs which tend to be far less filling. In fact, studies have shown that it’s actually the high protein content of the diet that helps control appetite and cause weight loss, not the avoidance of carbs.123

          Enjoying previously taboo foods, eating more protein and fat, and not being told to restrict calories drives people in the low-carb groups to eat less and report they’re eating more than they really are.

          Researchers generally must exclude participants who routinely go about flouting the laws of physics as we know them, so yes, it would still apply in this study.

          Which participants violated the laws of physics?

          I have a much less exciting way of thinking about it. Different food molecules play different roles in both metabolic structure and signaling processes. How do you “count” the calories in a group of amino acids (from a protein molecule ostensibly “worth” 4 calories) when they are used for creating something in the body that wasn’t there before (an enzyme, a bone cell, a hormone)? They are being “conserved” as in accordance with the first law, but they are not being “stored” or utilized for energy needs—oh, and sometimes they get mangled along the way and can’t be used at all (a little H pops off and rolls under the couch where you can’t get it, that sort of thing). What if it takes more “calories” to digest, dismantle and reassemble into something else one type of food “calorie” compared to another? What if one kind of “calorie” sets off a chain reaction that upregulates the transcription of enzymes that makes it easier for the body to store fat (as in the stimulation of the production of xylulose-5-phosphate through the pentose phosphate pathway resulting in the activation of ChREBP)? Nope, just the calories, ma’am?

          How does the fact that calories from different sources are used for different purposes prove calories don’t count?

          Hormonal levels and enzyme activity can be affected by the *type* of food molecules you consume or even the type of food molecules that your mother consumed, not just sheer amount. Crazy, huh?

          Neither Alan nor I said that different foods don’t have different effects on hormone levels or enzyme activity. Not has just about any weight loss researcher — ever.

          Do you have to consume more calories than you utilize in order to gain weight? Do you have to utilize more calories than you consume in order to lose weight? Yes, in terms of first law energetics—but this tells us exactly nothing.

          It tells us that calories count, which is the point of the article.

          Not sure why this is so offensive to some. I’m just saying, it’s complicated.

          I’m not offended — amused maybe. So, without writing another 10 paragraphs, can you describe what you think causes people to lose and/or gain weight, and what you would do to facilitate either of these goals?

          So far it seems you’ve done exactly what Feinman and Fine have done in their multiple reviews over the last decade — detail a bunch of irrelevant theoretical molecular pathways that prove absolutely nothing in terms of weight loss or weight gain, and ignore realistic, controlled trials that disagree with your position.

          If you can clarify your position that would be much appreciated.

    • says

      Adele — in addition to the important points that Ben raised, consider the following outcomes in the Volek et al study you cited:

      – The LC group lost 1.9 kg more fat mass than the LF group. However, the LC group also lost 2.4 kg more lean mass than the LF group. This supports a point Armi made: water loss on LC is often conflated with fat loss, when in many cases water loss is the more substantial outcome.

      – You claimed that the LC group ate the equivalent of 1 oz more per day in protein. This is incorrect since protein intake by week 12 in the LC group was 105 g, and it was 72 g in the LF group. This 33 g difference is the equivalent of a 4 oz piece of meat. This protein intake difference is easily enough to influence outcomes in favor of LC, especially since the LF group barely met the RDA level of protein (which has been shown to be sub-optimal in multiple studies with multiple conditions of energy balance).

      – You claimed that the groups ate about the same amount of calories. However, the LC group consumed 847 kcal less than baseline intake, while the LF group consumed 604 less kcal than baseline. Although the 247 kcal difference was not considered statistically significant, it still adds yet another fat & weight loss ‘advantage’ to the LC group.

      Please address these points if you would.

      • says

        Hmmm. 33g of “protein” equals 4 oz of “meat” (whatever you mean by that, there are lotsa different kinds of meat)? I believe that I was comparing 33g of *protein* to a little more than 1 oz of *protein* for the metrically challenged in our world. We can talk about the molecular components that make up our food or we can talk food, but those are different things. Protein can come from lots of places, not just meat—ask a vegan.

        The LF group—at an average of 72 g/day—easily met the RDA for protein (46 g/day for adult women and 56 g/day for men). I would agree that the RDA is probably an underestimate of protein needs, but I think the argument made above is that protein increases satiety so that fewer calories are consumed when protein is increased. So lessee, the LC group ate a whopping 33g more *protein* (from some food source—maybe even 4 oz of “meat”!!!!) and thus they should have felt more full and should have eaten lots fewer calories, but instead they ate more calories—oh wait, but the difference is not significant, so it probably doesn’t make sense to even talk about that.

        Oh, but you like talking about non-significant differences in group means? OK. Even when the amount you are talking about is half the SD? Alrighty. So if I understand correctly, you’re saying that there is this (non-significant) difference in calorie reduction that gives the LC group some kind of fat and weight loss “advantage”—even when the overall fat loss was not significantly different between groups? If that’s the case, what the heck is going on here? With that kind of “advantage,” hmmm, lessee—247 times 84 days carry the one, divide by 3500 kcals per pound of fat because there’s 9 calories in a gram of fat, oh wait, unless they are losing muscle mass, then it’s different because muscle is protein and that’s only 4 calories, and hang on, if they’re losing water, that’s no calories, omg—math is HARD. Let’s just say they should have lost LOTS more fat—or lots more fat and muscle and water—from all over their bodies.

        But that “advantage” was only (significantly) different w/r/t abdominal fat? Whoa. That’s crazy. How did they get their calorie “advantage” to come mostly from their abdominal fat and not indiscriminately from energy stores all over their body, since it’s just the energy that counts, right? Or perhaps metabolic signaling (related to particular macronutrients) had something to do with it? See above for the whole mobilizing/utilizing metabolic milieu gabfest.

        Lean mass losses were not significantly different between groups either, but feel free to talk about them if you want to. And I don’t recall suggesting that water loss was not some portion of overall weight lost in either group (even though water doesn’t have *any* calories). Thanks so much for inviting me to address those issues you raised. That was fun.

        • says

          Adele,

          1) Looks like you backpedaled on a mistake (or at best a misleading statement here). To quote you: “protein intake was higher in the LC arm, by an average of an ounce/day, if that’s your idea of “higher” protein intake; both groups seemed to be eating adequate protein.” <—- Clearly, you were trying to convey that this difference in protein intake was small and lacked any functional consequence – that’s simply false.

          2) They ate more calories, true. But you missed the point (or ignored it), which is that the LC had a greater calorie drop compared to baseline intake. This difference did not reach statistical significance, but your choice to ignore it completely fits in well with your predetermined stance that this study strongly supports LC, all while ignoring the greater protein intake advantages I mentioned previously. As for the hypothetical math, the LC group 1.9 kg more fat and 2.4 kg more lean mass (which is about 75% water if we're assuming it's muscle). The 247 kcal difference is not too far-fetched from accounting for this difference. Once again, this is speculative, so please keep the discussion in perspective.

          3) I'm glad you had fun responding, but please yourself and give this a read, it nicely reflects the points I've made about higher protein, as opposed to lower carbs (this is something you're purposely ignoring): http://www.ncbi.nlm.nih.gov/pubmed/22935440

        • says

          Adele, the reference Alan just reminded you of was also in the article in support of this statement:

          People on low-carb diets often eat more total protein and fat, which helps blunt their appetite.65-70,122 In contrast, the people in the high-carb groups in these studies are often eating lots of refined carbs which tend to be far less filling. In fact, studies have shown that it’s actually the high protein content of the diet that helps control appetite and cause weight loss, not the avoidance of carbs.123

          123. Soenen S, Bonomi AG, Lemmens SGT, et al. Relatively high-protein or “low-carb” energy-restricted diets for body weight loss and body weight maintenance? Physiol Behav. 2012;107(3):374–380. doi:10.1016/j.physbeh.2012.08.004.

          As Alan said, you’ve been ignoring this — despite it being in front of you since the publication of this article.

        • says

          But that “advantage” was only (significantly) different w/r/t abdominal fat? Whoa. That’s crazy. How did they get their calorie “advantage” to come mostly from their abdominal fat and not indiscriminately from energy stores all over their body, since it’s just the energy that counts, right? Or perhaps metabolic signaling (related to particular macronutrients) had something to do with it? See above for the whole mobilizing/utilizing metabolic milieu gabfest.

          There wasn’t a calorie advantage, since they both lost similar amounts of fat. As Alan pointed out, the differences in fat loss could easily be explained by small non-significant difference in calorie intake.

          You’re also choosing to ignore the other studies references in this article. It seems your desperately trying to defend the less than spectacular results of a single study to prove your point. While ignoring the ones that (also) don’t prove your point.

          It’s also not news that people lose different amounts of fat from different parts of their bodies. This doesn’t prove calories don’t count. The subjects in this study also had atherogenic dyslipidemia — they were not healthy — and other studies have also found that low-carb diets tend to produce greater losses in visceral fat and improvements in metabolic markers in the overweight/obese with metabolic syndrome. The article didn’t say that low-carb might not be preferential for some. It simply said that no matter what diet choose to eat — if it has an excess of calories they’ll gain weight and visa versa.

          Given the sample size of the study, it’s also entirely possible the small difference in abdominal fat loss, after accounting for differences in calorie intake, may have been due to chance.

    • says

      In addition to Alan’s respone, I want to point out that your second point is also invalid. You write:

      2) if there was reporting error, it would be randomized; both groups could be expected to over/underreport to the same extent

      The article included a detailed discussion of why that is not a reasonable assumption:

      It’s likely that the people on high carb diets are more likely to underreport their food intake. This would make it seem as if people on low-carb diets are losing weight despite eating more calories.

      The people on high carb diets in weight loss studies are often told to consciously restrict their calorie intake and avoid “unhealthy” or “bad” foods, especially fat. These are all behaviors that generally increase the likelihood that people will underreport their food intake.81,92,97-101,121

      On the other hand, the people eating the low-carb diets are often told to eat as much fat and protein as they want.

      Remember that most of these people were probably making some attempt to control fat intake before the study, or were at least used to the idea that fat is “bad” (thanks largely to the USDA, FDA, and other health agencies). When they’re told to eat a low-carb high-fat diet and to eat as much of these previously “forbidden” foods as they want, even small amounts can feel like a lot of food.

      People on low-carb diets often eat more total protein and fat, which helps blunt their appetite.65-70,122 In contrast, the people in the high-carb groups in these studies are often eating lots of refined carbs which tend to be far less filling. In fact, studies have shown that it’s actually the high protein content of the diet that helps control appetite and cause weight loss, not the avoidance of carbs.123

      Enjoying previously taboo foods, eating more protein and fat, and not being told to restrict calories drives people in the low-carb groups to eat less and report they’re eating more than they really are.

      It’s certainly possible the misreporting may have been randomized, but most of the evidence indicates it would favor outcomes in the low-carb groups. When you pair this against the data that’s shown no difference in weight or fat loss under controlled conditions, then it seems even more likely that people in the high-carb groups are underreporting more.

  13. says

    Excellent article. Well written and well supported. While i have not researched this specific topic myself, I have trained hundreds of clients to lose weight successfully using this basic principle of calories in vs. calories out. Unfortunately I do not have access to a calorimetry machine or lab where I train. So I use trial and error to figure out what works.

    I have always said that weight loss/gain begins with cals in vs. cals out. The rest is optimization of health, performance, etc.

    Great post! Glad I stumbled across it.

    • says

      Glad you liked it Tim. You raise a good point about not having access to advanced testing methods. The cool thing is that they’re unnecessary. As you’ve found with your clients — it’s the person’s relative calorie intake that really matters.

    • Mike Hammer says

      And I’d like to add that my macros has been 70% fat/28% protein/2% carbohydrates.

      HDL is very nice, LDL is very nice, triglycerides are very low. And I haven’t exercised anything at all.

    • says

      I must disagree with the study of the low-carb diet.

      Which one?

      I’ve been in ketosis for almost three months now, and I’ve measured my body fat with DEXA before and after.
      I’ve lost around 1 kilogram in fat free mass, and 12 kilograms of fat.

      Mike, the first 1/3 of the article went through why proper control over variables such as calorie intake and energy expenditure are essential to drawing and conclusions about weight loss. You haven’t controlled for any of these. Even if you did, your “experiment” would be biased from the beginning since you went into it specifically because you thought it would work. Plus there was no blinding, or validation, or supervision, or weighing of food… or anything else that would remotely prove your point.

      DXA scans are also significantly altered by changes in hydration status, which you did not control for (nor could you have). DXA scans can also be off by up to 8-10 percent for individuals.

      I’ve lost around 1 kilogram in fat free mass, and 12 kilograms of fat.

      Congratulations. It’s great you’ve found a diet that helps you consume fewer calories.

      I recommend that you watch this http://www.youtube.com/watch?v=M6vpFV6Wkl4&hd=1

      I read the book.

      • Mike Hammer says

        I’ve tried eating less before, with carbohydrates, and it didn’t work as well as after i started a LCHF-diet.

        I tried VLCD for a couple of months – what the hell was I thinking. Felt like shit, had small losses I gained right away (only measured on scale).

        I tried eating healthy and less, but still with carbs, around 1600-1800 calories a day. Had big problems with being hungry all the time, and craving for that damn junk I had been eating for years, essentially fell off the wagon after 2 months, had a stall in fat loss (only measured on scale).

        That’s why I’ve fell in big love for a LCHF-lifestyle. For a guy who’s never managed to keep up with a diet, always ending up eating shit all the time, I totally changed my lifestyle, because I enjoyed the food. Never felt any cravings, enjoyed the food, didn’t feel hungry all the time.

        That’s why I disagree with most of it being water weight, I would agree that it is in the beginning which is very motivating (but also in the back of my head), but after getting measurable results after the quick losses you get the first weeks, I finally felt something was working.

        I’m not sure if it had any effect, but I had the DEXA-scans at the same time in the morning fairly close to after I woke up. Went to the bathroom, but didn’t eat or drink anything before after the measurement. It’s my usual morning routine when measuring on the standard scale in my bathroom.

        I truly enjoy watching and reading material from Gary Taubes, and I’ve truly come to hate carbohydrates. I’ve never felt happy about is. What are your thoughts of Gary Taubes philosophy when it comes to carbohydrates? And what do you think about the Paleo-diet?

        • says

          I’m sure Armi has a bunch to say about this, but if I may interject, personal anecdotes are fine, but they are not strong evidence since they are uncontrolled & plagued by a wide range of biases. We’re discussing objective data here; if this was all about sharing our personal testimonies then we’d have all kinds of stories to wade through. As Armi said, you’ve found a diet that allowed you to finally adhere to a caloric deficit. And my hunch is that you finally started eating adequate protein (& who knows, maybe adequate fat too).

          Taubes is a good writer, but he’s biased & incomplete in his reporting. He cherrypicks data to fit his pre-existent beliefs; he’s not a scientist who bases his opinions on the totality of the current evidence. The carbs->insulin->obesity hypothesis is majorly flawed (Google a 5-part article series called “Insulin: an undeserved bad reputation” by James Krieger). As for the Paleo diet, I’ve dissected most of its claims here: http://www.alanaragonblog.com/wp-content/uploads/2013/07/Paleo-Diet-Claims-Vs-Evidence.pdf

        • says

          I’ve tried eating less before, with carbohydrates, and it didn’t work as well as after i started a LCHF-diet.

          It’s good low-carb has helped you maintain a caloric deficit better than a high-carb diet.

          I tried VLCD for a couple of months – what the hell was I thinking. Felt like shit, had small losses I gained right away (only measured on scale).

          Maybe try a less extreme diet next time. Changes in water weight can often account for the changes in total weight loss after hard dieting and refeeding.

          As for your other comments, Alan already covered them well.

          I truly enjoy watching and reading material from Gary Taubes, and I’ve truly come to hate carbohydrates. I’ve never felt happy about is. What are your thoughts of Gary Taubes philosophy when it comes to carbohydrates? And what do you think about the Paleo-diet?

          I’m sorry you feel the need to hate a food group. What have you not felt happy about?

          I think Gary Taubes has written some excellent articles — his latest work is less impressive. He selectivity cites research to support his positions and relies on anecdote. Then he ignores controlled research that contradicts his views. He’s completely incorrect about carbohydrates being fattening without a calorie excess and pretty much everything else on the topic. To his credit, his work on saturated fat and cholesterol is quite good for the most part. If someone asks me about Good Calories Bad Calories, I usually tell them to read the first part of the book and stop after he gets to talking about carbs and insulin — if they want the accurate parts.

          Here’s the link to James Krieger’s series on Insulin:

          Insulin…an Undeserved Bad Reputation

          Stephan Guyenet also has an excellent rebuttal of the carbohydrate hypothesis of obesity here:

          The Carbohydrate Hypothesis of Obesity: a Critical Examination

          • says

            Armi – You wrote:

            “To his [Gary Taubes] credit, his work on saturated fat and cholesterol is quite good for the most part. If someone asks me about Good Calories Bad Calories, I usually tell them to read the first part of the book and stop after he gets to talking about carbs and insulin — if they want the accurate parts.”

            This is completely false. Taubes is far from accurate when it comes to dietary fats, cholesterol and etiology of CVD. First part of the book is as clueless as the rest of it.

            For those interested in this topic, I recommend two books: (1) Cholesterol and Beyond: The Research on Diet and Coronary Heart Disease 1900–2000 by A. Stewart Trusswell, emeritus professor of molecular and microbial biosciences, University of Sydney, Australia; and (2) The Cholesterol Wars: The Skeptics vs. the Preponderance of Evidence by Daniel Steinberg, emeritus professor of medicine in University of California. Both are heavyweight veterans in their field. Steinberg’s book includes a foreword by Michael Brown and Joseph Goldstein, who were awarded the 1985 Noble Prize for Physiology or Medicine for their studies regarding cholesterol metabolism.

            Otherwise, good comments and great article! Very thorough work.

          • says

            Hey Jussi, thanks for the comment. I’m always open to new evidence and frankly I don’t like relying on Gary Taubes’ work to prove just about anything at this point.

            Would you provide some references and key points from the books you mentioned that indicate cholesterol and saturated fat do contribute to heart disease more than other dietary fats or nutrients?

            It’s definitely a topic I hope to explore further in the future. Let me know if you have any other resources you’d recommend.

          • Frank says

            Hi Armi.

            If you are interested in further discussion of that matter, Plant Positive’s nutrition series on youtube is the best thing you can spend your time on.

            http://www.youtube.com/watch?v=egqf7k5Lzhk

            There is well over 15 hours of running material there, but you will learn why cholesterol and SFAs do matter – actually, are about the only thing that matter – when it comes to CHDs as well as seeing most of the paleo claimed being debunked.

      • says

        Holy Shit! Did not know that about DEXA. That is a huge margin of error. I’m gonna have to look into this a bit more b/c that’s higher the even a skin fold caliper from what I recall. Is it mostly thrown off by hydration status? And is there a way to control for this to improve accuracy?

        Off topic, I know, but it’s very interesting to me.

        • says

          Hey Tim, thanks for the questions. I was pretty shocked at this too actually. I think this is mostly due to differences in hydration status. but unfortunately there’s not much you can do to control for it. There’s also just some variation from the device itself. I generally like a combination of calipers, scale weight, and pictures/mirror test to gauge body fat percentage. No one really cares what exact % of body fat they are, they just care how they look/perform. So for the most part, I don’t think DXA is a great use of time or money for individuals.

          • Brian Snyder says

            Do you have any/the references to the DXA margin of error that you cite? I had not heard specifically about the margin of error being that large. I know the CV for repeated scans is relatively small (and differs with the tissue type [BMD / LBM / Fat mass). In some unpublished data using repeated scans (back to back), a fellow colleague was consistently getting less than 0.4% variance in total BF %. I don’t recall if she measured hydration as a part of that data set.

            Thanks.

            (if you can…email me the refs if you have them)

  14. says

    I meant to comment earlier to offer you praise, Armi. This is a fantastically written and referenced piece, and one I will definitely refer to often, I’m sure, in my debates with calorie deniers (who tend to be low carbers and yes, fat).

    Keep up the great work. I look forward to future articles. Please let me know if I can ever assist in your article writing! I find this area fascinating.

  15. says

    I like this study for showing the very pronouced effect of a higher protein, lower carb meal on satiety and overeating. It is also nice in that it compares 3 different meals, 2 with higher carbs each with different glycemic index, and the other with different macronutrient makeup. All meals had the same calories. The boys in the study had the same meal for breakfast and luch and were then allowed to eat whatever they wanted for the rest of the day. Intake following the higher protein meal was almost half of that following the carbohydrate meals. http://pediatrics.aappublications.org/content/103/3/e26.full
    The reason was the effect of different macronutrients on hormones and blood sugar http://pediatrics.aappublications.org/content/103/3/e26/F1.expansion.html
    Hormones and blood sugar had a significant impact on hunger
    http://pediatrics.aappublications.org/content/103/3/e26/F2.expansion.html
    Which then had an impact on food consumption
    http://pediatrics.aappublications.org/content/103/3/e26/F3.expansion.html

    So as you say calories count, but to control caloric intake hunger needs to be controlled, and this is where macronutrients and food quality counts

    • says

      Thanks for sharing Julianne, and I agree with you. Sometimes simply eating less works, but for most people a qualitative change is also necessary to create a caloric deficit over the long-term.

  16. says

    Really great article, and you are absolutely right. There is so much more to weight loss than calories in vs. calories out. No one way will work for two different people. People have to experiment and find what works best for them.

    • says

      Thanks Miller. Weight loss is about calories in versus calories out, but finding a system that helps someone accomplish that is the hard part. You’re right — implementing a calorie deficit is highly individual.

  17. says

    Good article.

    In practice I’ve found that there are several ‘levels’ of calorie intakes that have different effects. Assuming no exercise…

    1. Taking in calories below BMR is most likely to causes fat AND muscle loss.
    2. Taking in calories equal to one’s BMR most likely causes fat loss, but spares muscle.
    3. Taking in calories over BMR, but below what one needs for labor (thus maintenance) is also likely to burn fat while sparing muscle.
    4. Taking in calories over maintenance is likely to store fat and spare or even build muscle.

    • says

      Hey Daniel, thanks for the comment.

      In general, whether or not you consume calories above or below BMR doesn’t really matter. What matters is the absolute level of calorie restriction. In most cases, consuming a calorie intake below BMR means pretty severe restriction, which general accelerates muscle loss. While the guidelines you mentioned probably work pretty well for most sedentary or mostly sedentary people, they wouldn’t be useful for people doing much training or who have higher energy needs.

  18. Marco says

    And Armi does it again, excellent article.

    After reading some of the comments above, I come to the conclusion that people are, indeed, always trying to find out something that confirms their pre-existing beliefs. Calories matter period.

    I know this is a bit off-topic, but do you use any reference management software? If so, which one?

    Thanks

    • says

      Hey Marco, thanks a ton man. :) And you’re absolutely right, people, including me, have trouble letting go of old ideas. Hopefully some will come around in time.

      I actually bought Papers for Mac earlier this year. I love it mainly because it has a really cool feature that lets you insert the references into your documents and formats the whole list of citations for you. Killer piece of software.

  19. says

    Thank you for a superb article. Well written and entertaining whilst also thoroughly well researched- an online rarity. You have crystallised what a thought was the situation far more eloquently than I ever could. You have also given me some new nuggets of info that are both interesting and useful- the DXA and differences in animal fat metabolism, to take just 2 examples. I will enjoy following up some of your numerous links and references too.
    Props to you also for hanging around to explain/defend your arguments in the comments section. Many authors shy away from this part, or cherrypick the easy replies. I know there’s a fine balance to be struck between silence and getting drawn in to endless and pointless arguments and/or slanging matches. I think you have struck a nice balance here.
    I didn’t doubt it, but it’s nice to be reassured that dietitians involved in weight loss like me are doing the right job in helping overweight people to find a system that enables them to sustain a significant calorie deficit for a sufficient length of time, whilst also maintaining a high quality diet and regular physical activity. You made both these points in your responses to comments. The simplicity of energy balance in a controlled system in no way detracts from the complexity of manipulating it in real life for free living individuals. I think it’s a shame that some commenter’s have mistaken the point of your article, seen it as an attack and allowed it to irritate them.
    Thanks again, I look forward to your future articles.

  20. Jovan says

    Amazing read, I took a lot away from this. I also watched this BBC documentary on low carb diets yesterday which undertook some original research and essentially backs up everything you have to say. If you haven’t seen it it’s here: http://youtu.be/laMuyJhMcE0

  21. grinch says

    What do you think of the Ludwig et. al. study from June 2012 that the low carb dieters still routinely cite as proof of the low carb advantage?

    • says

      Armi,

      Good topic. No matter how you cut it it is calories in versus calories out. I have found people who are looking to lose weight tend to overestimate their caloric consumption.

      Where as individuals looking to gain weight underestimate their daily caloric intake. A food journal can be a very useful tool to keep an individual honest and on track!

      Lisa H

  22. Michael Stephensen says

    Hi Armi,

    As you’ve suggested, Weight Watcher’s and most other successful diet programs are basically surrogates for calorie counting.

    I’ve had some success with a phone calorie counting app. I guess many of us are looking for a simple but accurate method. “Easy” means it will actually happen in people’s busy lives.

    What would you suggest as the calorie counting method that has the best “Most effective / easiest” ratio.

    Thanks,

    Michael

  23. says

    Whoa.
    Wow.

    This is probably the most complete, succinct and well referenced weight loss / gain explanation I’ve ever come across.

    Brilliant.

    What about gaining weight and losing fat mass via a calorie surplus? Losing weight while gaining lean mass via a calorie deficit? Possibly? Easily explained? Significant research I could look into?

    (There’s this one, where guys started lifting weights + consuming tons of surplus calories from protein and carb powders (whey and maltodextrin I believe), gained a bunch of weight and came out leaner: http://www.ncbi.nlm.nih.gov/pubmed/12094125)

    Again, great article!

    -Shane

  24. ML says

    Thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, THANK YOU!

    I have been yo-yo dieting since I was 8 years old. I recently lost almost 100 pounds in about 6 months on a low-carb Paleo diet, and then promptly gained it all back again.. I blamed myself and lack of willpower for this, but after so many failed attempts, I had to wonder if I was simply going about it the wrong way. I’ve looked everywhere for an article that would break this down for me and used actual evidence instead of “bro-science,” but it’s a lot harder to find than I thought!

    I finally feel like I have sufficient evidence to know what I need to do: Accurately track my calories, eat at a reasonable deficit and stick to it.

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