The calorie theory of obesity falsified


Is a calorie a calorie? Clearly not. And now, via the recently reported Kevin Hall/NuSI study we have even more evidence that a calorie is not a calorie.

What this study did was have a group of overweight or obese people start on a regular diet – 50% carbs, 15% protein and 35% fat. Then they maintained exactly the same calorie intake (they were all locked inside a metabolic ward, so we know what they ate) but switched most of the carb calories to fat calories. They switched to an LCHF diet of 5% carbs, same 15% protein and 80% fat.

Got that? All they did is change most carb calories to fat calories. Everything else was exactly the same.

Calorie theory

The calorie theory – “a calorie is a calorie” – predicts that nothing exciting would happen when switching to low carb (the pink areas of the charts above). The energy expenditure would stay exactly the same on both diets. The charts would show straight lines.

But that’s not what happened. Suddenly people started to burn significantly more calories (top chart above), even while they were sleeping (bottom chart)!

Calorie theory falsified. This has actually been shown before in other studies too.

Insulin theory

The insulin theory mainly predicts that people will tend to lose fat mass on a diet that lowers insulin (like a low-carb diet). This probably mainly happen through reduced appetite and reduced need to eat – something that was not tested in this study (remember people were forced to eat the same number of calories on both diets).

If people also burn more calories (when they have excess weight) this would be a bonus – a cherry on top. This low-carb ketogenic study proves again that there is actually a cherry on top, when it comes to weight loss on low carb.

The increased energy expenditure of about 100 calories per day – in this study – would match the energy burned during 30 minutes of moderate exercise three times a week. Not a bad bonus. Earlier studies have shown even larger advantages.

So why do not everyone agree? I recommend this (long) post by Dr. Michael Eades:

Dr. Eades: Contradictions and Cognitive Dissonance: The (Kevin) Hall Effect


For more on this study – and the normal “Biggest Loser” SLOWDOWN of calorie expenditure check out this earlier post:

Dr. Fung: The Biggest Loser FAIL and That Ketogenic Study Success

Try it yourself

Do you want to try a low-carb and ketogenic diet yourself? Use these resources:



The Cause of Obesity and Diabetes – Gary Taubes
The Top 5 Tips For Weight Loss
Weight Control – A Question of Calories or Insulin? – Dr. Andreas Eenfeldt
The Key to Obesity – Dr. Jason Fung


  1. 1 comment removed
  2. PhilT
    They forgot to feed them more too, it was supposed to be eucaloric.
  3. Zepp
    Its kind of surprising.. they must be feed a low calorie diet at first!

    Why they did that I dont know??

    Im all in with Eads anyhow.. it shows that a LCHF diet increese EE!

    Im not that fund of MAD theorie at all.. im more in for reduced apetite, for those that are obese.

    Thats the more resonable outcome when one get acces to more stored energy.

    And then I dont call this an metabolic advantage.. but a adjustment of ones homeostasis.

  4. YAT
    Really? If you disregard the adaption fase to LC-diet, the first 2-3 weeks after transition when the body struggling with produce glucose from protein via GNG until the ketogenesis reached full capacity, and just focus of the period when the are fully adapted to the LC-diet, do you really see that much difference in EE and SEE? I sure don't.

    If there were any metabolic advantage (evolutionary disadvantage), for fat in comparioson with carbohydrats, the difference i energy expenditure would be consistent throughout the hole study. And it's not. Actually, in the end of the study the energy expenditure is about the same as it was on the baseline diet. Where is the difference there?

    Just sayin'

  5. YAT
    About that study that you gave us above in two different links, (it's the same study though) the protein wasn't the same between diets. And as we already know protein has greater TEF which create a difference in energy expenditure. If you want to compare fat to carbohydrats effect on energi expenditure you have to keep protein the same and compare when you're fully adapted to the diet.
  6. George J.
    Phinney & Volek will be happy to tell you that there's no advantage. Wortman will tell you there's no advantage. I know Ludwig touts his 2012 JAMA study to this day, but ... he likewise misinterpreted his data. Those who know the field best admit there's no advantage. The NuSi study likewise shows no advantage. We don't need advantage. Truly. All we need is to keep basal metabolism high even as our ketones allow us to burn body fat. The sooner we give up this specter of "advantage," this poor science, the more acceptance we will gain. :D Best wishes.
  7. Tor H
    Yeah and on top of that it's kinda hard to gain weight on LCHF, even if we overeat.
    But it's very easy to gain weight on a "normal" diet low in fat and high in carbs, just like in the US :)
  8. Zepp
    Let put it in this way then.. presume that there is a small.. small, metabolic disatvantage on a ketogenic diet!

    Then this would be Glukoneogenesis.. its an energy consuming thing to convert amino acids to glucose!

    Let say this use 100-300 Kcal a day.. waisted energy?

    Presume then that you have a normal apetite regulation.. then you get hungry for that waisted energy.. its then a zero sum game!

    I wisch next studie would be a study about apetit regulation.. on different persons!

    Becuse thats my favorite approch way LCHF works for some people.. then its about insulin again.. and its regulation of Lipolysis!

    I have no doubt about if people dont have problems with Lipolysis providing enough FFA betwen meals, dont have that much benefits of the diet beside that they get to eat delicius food!

  9. Aidan
    Can I not read a graphs?

    After initial steep climb In energy expenditure there is a decline in burn rate which looks like it might head towards, a very low rate possibly zero. I can see how Kevin interprets the trend line, to come up with a negligible burn rate....especially if he makes forecast for later date. This study lacks the amount of research to be conclusive.

    I am disappointed the data is not more compelling, but I am confident LCHF is still the way forward for me.

  10. Coach Sahil
    Talking about jumping the gun on a study that hasn't even been fucking PUBLISHED yet.

    Brad Schoenfeld couldn't have said it any better:

    "So now we have keto proponents spinning the results of the recent Taubes-funded study, saying that: "The increased energy expenditure of about 100 calories per day – in this study – would match the energy burned during 30 minutes of moderate exercise three times a week."
    One little problem: The increase in EE persisted for about 10 days and then rapidly trailed off to almost zero after ~3 weeks. Oops! Apparently confirmation bias runs strong.
    At this point all we can go on is the abstract and the explanation of the findings by the lead author, Kevin Hall, which to the dismay of some appear to refute the insulin hypothesis of weight loss. Let's wait for the study to be published before drawing conclusions, and certainly before extrapolating implications that are not consistent with available data."

  11. Lyle McDonald
    Let's see, that 100 calorie increase persisted for about 10 days.

    1000 calories extra.

    1/3rd pound of fat extra.

    Whoop de do.

    And this doesn't disprove anything in the least. For a diet 'doctor' you don't know shit.

  12. ron
    Lyle sounds like gentlemen on various podcasts I listen to, but here he's just insulting.
  13. Garry
    Firstly, I would expect no increase in calorie burning. Why? I don't believe in the metabolic advantage.
    Secondly, the extra calories burnt for 10 days was protein, i.e. lean body mass.
    Thirdly, I am wholly committed to LCHF.

    Why am I so when there's no metabolic advantage?
    Because it works, it controls hunger and it fixes the diabetogenic effects of the "modern" i.e. appalling diet.
    The metabolic advantage, even if it worked, is of NO importance. None at all. What is important is that for somebody like me, who first had a "belly" at the age of 23, i.e. is clearly IR, this is the only solution. I'm on it for 30 months and have had my weight at its ideal for 24 months. I don't cheat and gave up sweeteners. Maybe that's why I don't regain.

    Where this recent trial was faulty, as far as I'm concerned, is that it didn't allow the participants to eat ad libitum. That is the reality.

  14. Allan
    Friends and clients of mine are getting good results with a LCHP diet, i.e., low carbs and high protein, not high fat.
    I'd like to see a discussion of why high fat would be superior to high protein, including any controlled studies that illuminated the comparison.
  15. Ravi
    For people talking about LCHP, that would be counteractive since excess protein would be converted to glucose and once the body gets glucose, the insulin spikes like it would if carbs were in the diet. Fat doesn't get converted to glucose and has no effect on insulin at all.

    So I dont understand how a LCHP diet can be better than a LCHF diet.

  16. Zepp
    LCHP is Dukan diet.. its often werry calorie restricted.. becuse if one dont ad more fat one cant eat that much protein.

    Any calorie restrikted diet is often verry good in the beginning.. or outstanding!

    The thing about LCHF is that one ad more metabolic advantages.. like high fat burning kapapacite, extra lipolysis, and satiety.

    LCHF often get a litte higher on protein anyway.. often anyway.

    Its not that if anything is superior.. if one lean on high protein one still lean on glucose.

    LCHF is about to lean on fat.. at least if one have a lot of fat to get rid of.

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