There Is No Single Cause of (Or Treatment For) Obesity | Chris Kresser

There Is No Single Cause of (Or Treatment For) Obesity


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One of the most hotly debated subjects over the past few years has been the cause of the obesity epidemic, and along with that, the best strategy for weight loss.

Some folks (Atkins, Taubes, Eades, etc.) believe that carbohydrates are to blame. Others (Ornish, Campbell, Esselstyn, Fuhrman, etc.) believe that fat is the problem. More recently, researchers like Seth Roberts and Stephan Guyenet and clinicians like Dr. Sharma have raised awareness of another hypothesis, called the food reward theory, which holds that the consumption of highly palatable foods leads to overeating and weight gain. And Paul Jaminet and others have argued that micronutrient deficiencies, toxins and infections may play a significant role in the obesity epidemic.

Here’s what I think: the most accurate answer to “why do people get fat?” and “what’s the most effective weight loss strategy?” is: “it depends.”

Separating Cause from Mechanism and Effect

One of the biggest mistakes often made in this debate is the confounding of cause, mechanism and effect. A classic example is the assumption that if reducing carbohydrate or fat intake leads to weight loss, then the original weight gain must have been caused by excess carbohydrate or fat consumption.

While it’s tempting to make such an assumption, the logic is faulty. It’s kind of like saying “Advil cures headaches. Therefore, headaches must be caused by Advil deficiency.”

Let’s look at some definitions.

Cause: something that brings about an effect or a result

Mechanism: the fundamental processes involved in or responsible for an action, reaction, or other natural phenomenon

Effect: an outward sign

Obesity is an effect. Insulin resistance, leptin resistance, lipotoxicity, disruption of the mesolimbic dopamine reward pathway and inflammation of the hypothalamus are presumed mechanisms. Excess consumption of carbohydrates, fat, highly palatable food and food toxins (wheat, seed oils, liquid fructose, etc.), exposure to environmental toxins (chemicals), stress, infections, etc. are presumed causes.

Say we do a study on obese people and we observe that they eat a lot of carbohydrates and are insulin and leptin resistant. It’s easy to assume that the chain of causality worked like this: normal weight person eats high-carbohydrate diet, becomes insulin and leptin resistant, and then becomes obese.

But again, this is faulty logic. There’s no proof that A (high carbohydrate intake) was what led to B (insulin and leptin resistance) was what led to C (obesity).

In fact, we could disprove that theory simply by observing another individual or group that eats a very high carbohydrate diet, but does not develop insulin or leptin resistance and obesity. Guess what? Such individuals and groups most certainly exist. There goes that theory.

Likewise, we could also disprove this theory by observing people that are insulin and leptin resistant, but don’t become obese. Such people do exist, and I’ve written about them in my series on diabesity and metabolic syndrome.

A More Rigorous Approach

How have we developed our theories on obesity and weight regulation? It seems to me they come from a blend of personal experience, belief and facts. And I think it’s time to become more rigorous about keeping them separate. Here’s an example of what I mean:

Personal experience: I lose weight on an low-carb diet, therefore low-carb diets must be best for weight loss.

Belief: carbohydrates are responsible for the obesity epidemic, via their effects on insulin.

Fact: many cultures around the world eat high-carbohydrate diets and are exceptionally lean.

Those who’ve lost a lot of weight on a low-carb diet have a tendency to become convinced that their wife, friends, family, plumber and everyone else will also lose weight following the same diet.

From this personal experience, a belief is formed. And once we believe in something, we have a remarkable ability to filter out any evidence that might contradict that belief.

This is especially true if our reputation or financial livelihood is tied to said belief. As Upton Sinclair famously said:

It’s difficult to get a man to understand something when his salary is dependent upon him not understanding it.

When a belief like “carbs cause obesity” is shared between enough individuals, it becomes a meme. Once that happens, it is accepted by most as fact – regardless of whether it has any scientific basis. Hence we had the idea for decades that eating fat makes you fat, and now the more recent idea that eating carbs makes you fat.

There’s No Single Cause (Or Treatment) of Obesity

Perhaps one of the reasons it’s so easy to confuse cause, mechanism and effect and personal experience, belief and fact is that obesity is an incredibly complex disease. Just how complex is it?

Click on the Obesity Systems Influence Diagram below to find out.

Click image for larger version

Wow. That should give you a rough idea of how many variables are potentially involved in weight regulation. Now you know why it has been such a challenge to come up with a single, unified theory of obesity.

That said, of all of the hypotheses advanced to explain the mechanisms behind obesity, I think the food reward theory is the most inclusive.

However, as even its proponents would agree, it doesn’t tell the whole story because there are people and groups that eat large amounts of highly palatable foods that do not become obese.

My opinion is that the modern lifestyle (i.e. food and environmental toxins, stress, poor gut health, infections, micronutrient deficiencies, sleep deprivation, etc.) interfere with hypothalamic hormonal regulation, dopamine signaling, leptin and insulin sensitivity at the cellular level, glucose metabolism and a range of other mechanisms that lead to obesity.

This is consistent with the observation that obesity is extremely rare or nonexistent in traditional cultures that do not consume modern foods and do not live a “modern” lifestyle.

But even this theory is incomplete, because there are people fully exposed to the modern lifestyle that do not become overweight or obese. This suggests that genetics, and perhaps other undiscovered factors, also play a role.

We’re Not Robots

Humans are not robots. We’re living, breathing, dynamic organisms influenced by varying genetics and environmental conditions.

Anthropological evidence combined with modern research has helped us to reveal the basic template of a species-appropriate diet. However, it has also shown us that humans can thrive on a wide variety of macronutrient ratios and foods within that basic template.

This is not a belief. It’s a fact, supported by the evidence as a whole. Ignoring the evidence doesn’t make it go away. Believing passionately in something doesn’t make it true. Experiencing something personally doesn’t make it fact for everybody else.

19th century philosopher Charles Peirce said:

The state of belief is a calm and satisfactory state which we do not wish to avoid, or to change to a belief in anything else.

And Tolstoy said:

I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives.

Recognizing this basic human trait, philosopher of science Karl Popper advised every researcher to earnestly try to discredit their own hypotheses.

That is no easy task, and it asks a lot of us. Yet intellectual rigor, emotional maturity and personal integrity are characterized by the capacity to question our own beliefs, no matter how deeply cherished they are or how much is at stake.

I sometimes wonder why we’re all so sure of ourselves. It helps me to remember that at every point in history scientists (and the general public) were convinced they had the right answers. At one time the world was flat, the earth was the center of the solar system and disease was caused by foul humors and could be cured by bloodletting.

Nowadays we look back on those fallacies with a smirk. But are we so arrogant to assume that our great-grandchildren won’t do the same?

The truth is, there’s far more we don’t know than we do know.


Join the conversation

  1. No offense Chris… but I think this article misses the point entirely. There will never be “one” grand unified theory for obesity… but just because there will never been one unified theory does not invalidate the other theories.

    There is no mystery about the cause of the majority of obesity in the US or the developed world… refined carbohydrates and sugar and the associated cravings they cause. Just because some people CAN handle a high load of carbohydrates and sugar without gaining weight, does not invalidate the fact that other people CAN NOT handle the same amount of carbs and sugar and become overweight.

    The difference is in the individual’s genetics. And there are also a very complicated set of hormonal interactions combined with genetics that predispose some people to gain weight on a diet of high carbohydrates/sugar.

    The scientific evidence (see Phinney and Volek’s recent book citing their studies as well as others) is mounting that a removing sugar and refined carbs from one’s diet decreases inflammation, increases good lipids, decreases insulin resistance, etc etc…. Wheat is also turning out to be implicated in brain malfunctioning…

    I think you are looking for the wrong problem…. rather than looking for one “accurate” theory of obesity, I think it would be better to look for what causes “some” people to gain weight, which again science strongly supports the refined carb/sugar theory for many overweight people in the US… just look at sugar/carb consumption graphs over the last 50 years in correlation with weight gain in the US… and, again, just because someone else does NOT gain weight eating the same way (eg different genetics and epigenetics) does not invalidate the theory for the people that became overweight on the same diet.

    Also, as Fred as pointed out, it is doubtful that anyone has become overweight by eating too many good fats, proteins and vegetables… you lose your appetite with that way of eating.

    As you point out, some people do not lose on a VLC diet… even tho inflammation is decreased and their lipid profiles improve… and that is attributable to hormonal imbalances such as hypothyroidsim (greatly undiagnosed in America), adrenal fatigue and off-balance levels of sex hormones. Check out for excellent pdf files explaining their intricate biochemistry in relation to weight loss.

    I love your website and your writings… I just think the logic is a bit faulty here. Just my opinion!

    • Carol,

      I’m not looking for an “accurate” theory or unified cause. In fact, the whole point of the article is that there isn’t one. I absolutely agree with you that the modern lifestyle (including diet) is at the root of the obesity epidemic, and that genetics predispose some to be more vulnerable than others. Toxins, stress, poor gut health and micronutrient also play a role in differing individual responses to modern food. I acknowledged this in the article, and I wrote about it in my series on diabesity.

      However, that does not mean that someone who is already obese will lose weight simply by eating a low-carb, real foods diet. That’s an important distinction, because I see patients in my practice all the time who are in this predicament. So yes, it’s important to me to determine how I can best help these people, and what I’ve seen is that a low-carb and/or Paleo diet does the trick in some cases, but not in others. Regardless of what the ultimate cause was (which you and I agree on: modern lifestyle + genetics), we still need to find a way of treating it and I’m arguing that a LC, whole-foods diet isn’t always successful.

      • Chris,

        You address one thing that I have been trying to find, for people that low-carb doesn’t work, what does work?
        If you have covered this previously I apologize.


        • Hi Chris and Justin,
          I have been curious about this as well. After eight months of eating Primal and LC, I have managed to gain about seven pounds, feel like crap, and now I have heart palpitations, which I am hoping are not related, but at this point I definitely wonder.

          I feel like going back to a full CW diet is clearly not the best choice, but yet although everything I read about Primal/VLC etc., makes sense, it is definitely not working for me.

          So I second Justin’s question: what does work?

          • What it means is to include lots of healthy starches in your diet: yams, sweet potatoes, potatoes, other tropical root veggies and white rice along with all the other wonderful ancestral foods you already eat. I’ve heard that even some types of corn grit may be safe, but I’m not sure that holds water with the whole anti toxin argument.

            As obviously stated here avoid processed flour, sugar and all omega 6 heavy foods (especially processed seed and nut oils). Minimize all fructose containing foods that aren’t whole (intuition would say that the nutrients in fruit do something to offset its fructose content, maybe its potassium and vitamin c content for instance).

            So you don’t have to throw out the baby with the bath water, just give your body lots of healthy starches to go along with your healthy fats, veggies, fruits, fish and meat. That isn’t too complex, is it?

          • Read Russ Farris, Potbelly Syndrome, and Paul Jaminet’s latest post:


            Both mention infection and toxins as possible causes for obesity.

            Farris suggests the mechanism that infection raises cortisol which leads to obesity. He also writes about the futility of dieting. See his website:


            There is a nice flow chart on his website about “Dysphoria and Obesity”.

            Here is his yahoo group:


            His book is well worth reading. It’s well written, sensitive and provocative.

          • I feel your pain. I was in a similar position seeing no weight loss eating LC and I also noticed my fasting blood sugar which has always been completely normal begin to creep up on the diet(up to 5.7 at one point!) which also went completely against the LC wisdom. I am not even diabetic but just check my blood sugars regularly. My solution was to reduce fat drastically and increase carbs. I stayed at the same weight but fasting sugars went back to 3.9-4.2 which is normal. All this told me is that my body has a certain set point, for some reason it wants to hold on to its fat. It makes the food reward theory very attractive in my book.

  2. ” it’s obviously not the whole story because there are plenty of people that eat sugar and wheat that don’t get fat.”

    I don’t see why this rules out excess sugar/wheat as the primary cause of obesity.

    Taubes often cites to a smoking analogy here. Nearly all lung cancer patients smoked, but not all smokers get lung cancer. This does not detract from the reality that smoking is the primary cause of lung cancer.

    Similarly, why can’t it be that obese people got obese from the excess sugar/wheat but not everyone who eats the excess sugar/wheat gets fat?

    Your thoughts are appreciated. Thanks!

    • There’s no doubt that sugar and wheat are primary contributing factors to the obesity epidemic, but not for the reason that Taubes, Eades and other LC proponents put forward (i.e. the insulin/fat storage hypothesis). You may think this is splitting hairs, and from the perspective of what to eat it may be, but it’s an important distinction in the discussion of what the causes and mechanisms of obesity are.

      The smoking analogy would only be relevant if we saw entire cultures that smoked heavily and had a zero or near zero incidence of lung cancer. Because there are several traditional cultures that eat very high amounts of CHO and have 0% obesity. That would be highly unlikely, to say the least, if high CHO intake alone caused obesity.

      • Don’t the Kitavans smoke a lot and have very low rate of lung cancer? I think both the CHO hypothesis (and counter-arguments) and smoking hypothesis are neglecting the bigger picture, which is that biological organisms necessarily utilize a variety of mechanisms to be robust against variable environmental condition.

        Suppose Seyfried is right, and that cancer is the result of mitochondrial stress. There are multiple environmental factors that can lead to mitochondrial stress. If you eliminate most of them and still smoke, your risk of lung cancer may be greatly reduced (essentially delayed, assuming mitochondrial damage accumulates).

        One other point: there doesn’t really seem to be a downside to eating “low carbohydrate”, assuming that you’re including some low glycemic fruits and veggies (and some might even argue the necessity of plants at all). So I’m not really sure what the fuss is about. It’s an interesting academic discussion, but as another commenter pointed out, does it make much difference from a practical standpoint? Assuming that we’re going to eliminate refined carbohydrates (including grains) and possibly legumes, what does that really leave to argue about? Potatoes? Snore.

    • … Some smokers don’t get lung cancer…YET.

      Most Smokers who don’t have lung cancer die from something else before they have a lung cancer diagnosis. Example: my husband’s grandfather quit smoking at age 51. At 94, he was diagnosed with end-stage lung cancer. He died 17 days later.

  3. Chris – Smoking causes lung cancer. But I can show you many people who smoke and don’t have lung cancer. However, smoking does indeed directly cause lung cancer. Lots of people eat huge loads of carbs and are not insulin/leptin resistant – yet. and if these same people are endurance nuts they can, by and large, get away with it.

    • Fred,

      That doesn’t hold water. The cultures I referred to often had relatively low levels of physical activity. They weren’t “endurance nuts” by any stretch of the imagination.

      Where is your proof that excess carbohydrates cause obesity, without some other contributing factor? So far, no one has come forward with that proof, and we have myriad examples that disprove that hypothesis. Therefore it is an indefensible hypothesis.

      • I thought Taubes addressed that in his book “Why We Get Fat” he goes through a litany of ‘primative’ cultures that developed obesity after introduction to flour.

        • Yes, but he was arguing that it was the dense carbohydrate content of the flour that made them obese, whereas I’m arguing that it’s more likely something else (i.e. toxins in the wheat, etc.).

          • If you follow the logic of WAPF or the Paleo/Primal community it would be the Phytic acid and other ‘anti’ nutrients that were never intended for human consumption. My limited understanding of it is that cereal grains have protective elements that prohibit digestion for the purpose of procreation. Once we process the grains so that they’re digestable we absorb elements that we were never meant to absorb.

            According to WAPF this is why traditional cultures would soak/sprout their grains before consuming them.

            • Perhaps insulin resistance is due to the fact that your body is trying to limit its exposure to these elements.

      • You two are talking past each other. Somebody define “excess carbohydrates”. Is it quantity? Total amount absorbed in the blood? Rate at which it is absorbed in the blood? Effect on total insulin secretion? Rate of insulin secretion? Etc.

        • Quantity would be a starting point. Jimmy Moore said that at the peak of his obesity he was probably eating 1,000 grams of carbs per day. That sounds excessive.

  4. A first-rate article!
    The one thing that many people miss is that processes aren’t necessarily reversible, so even if X causes obesity, removal of X may not reverse it. Asbestos causes cancer, but removing it won’t cure it. Most people are justifiably interested more in the possibility of reversal rather than in understanding the cause. The question is, “what’s the “Y” that can cause a reversal?”.

  5. Fred:

    Taubes does say that carbs are the problem in his book, although he acknowledges that refined carbs are worse. I do think refined carbs contribute to obesity, but as Stephan asked in his latest point, the key question is “why”? Taubes et al say it’s because carbs raise insulin and increased insulin causes excess fat storage. Stephan’s latest post clearly proves those hypotheses are false. (

    The fact that you will never observe an obese person who has lived his life eating only fatty meats, veggies and some fruits has nothing to do with the fact that they’ve avoided carbs, and everything to do with the fact that in eating only those foods they’ve avoided the processed foods and “neolithic agents of disease” that disrupt homeostatic and hedonic regulation of energy balance.

    While it’s true that I might put an obese patient on an LC diet, that does not mean carbs were the cause of obesity as I pointed out in the article. This is an important distinction, because one thing that has happened in the Paleo community is that even metabolically healthy people have put themselves on LC diets in an effort to prevent weight gain. I have many patients come to me on LC Paleo diets with a range of complaints that resolve when I have them start eating more CHO.

    It’s also true that a VLC diet does not work for all obese people, or its effect is short-term in others. That’s another reason why it’s necessary to be rigorous in our language and approach.

    There is no “insulin” issue as described by Taubes and Eades. Stephan’s recent article demonstrated that quite clearly. There is a leptin issue, but it’s caused by food and environmental toxins, LPS/intestinal permeability, stress and micronutrient deficiencies – not excess CHO intake.

    • Guyenet didn’t prove Taubes’ hypotheses are false. He just presented counterarguments and contrary opinions largely held by mainstream scientific community. While I do think Stephan raised some valid points, I still believe we need to give Taubes a chance to respond before we jump to definite conclusions. It’s not like Taubes made it all up and never backed his theory with scientific evidence. As a matter of fact he came up with two highly praised books, which takes a lot of research and thinking, much more than writing a blog post or two.

      In my view “the food reward theory” is just another way of saying we get fat because we overeat. How innovative is it? Many problems have been raised about the food reward theory: how do we design and conduct a controlled study to prove it or disprove it? Is the “reward value of food” an utterly intrinsic property of a given food or is it subjective, that is it differs from person to person depending on who is consuming it? Would it be possible to measure how rewarding a food is before we eat it? Also how do we tell the cause from effect: are we eating rewarding foods and thus gaining weight or are we gaining weight and consequently opting for more rewarding foods? Finally is “the food reward theory” even a falsifiable one?

      Noone claims , at least as far as I know, that obesity has simple roots and mechanisms. Of course it is multifactorial. However, scientists should be looking to identify and explain even potential causes rather than escape into mutlifactorial speculations and increasingly complex mechanisms that tell us nothing about why we get fat in real life. In my view “The Multifactorial Theory of Obesity”, FRT being part of it, is more and more popular, because it allows to reconcile different, even conflicting views of obesity under a single umbrella, and we want to be in agreement rather than at odds with each other. It helps to explain everything as it explains nothing. Let’s not cling to it, let’s not take that easy street, unless we wanna give up on our search for meaningful answers.

      That said, I really appreciate your work Chris. Many thanx!

      • Ansgarr said: “It’s not like Taubes made it all up and never backed his theory with scientific evidence. As a matter of fact he came up with two highly praised books, which takes a lot of research and thinking, much more than writing a blog post or two.”

        His books have actually received a lot more scientific criticism than The China Project.

        If mainstream science and the vast majority of the scientific bloggers (Guyenet, Harris, Masterjohn, Jaminet, etc…) in the paleo-sphere believe the Carbohydrate Hypothesis is wrong, why become so attached to it? A “book with a lot of footnotes” is the The China Project all over again. “I don’t like {meat|carbs}, and this book with a lot of footnotes makes me happy that science agrees with me.”

        This is a particular issue within the Ancestral Health movement. How can the movement be tenable in the long run when a big chunk of the movement prefers “a book with a lot of footnotes” over the criticism of the scientific heavyweights in the movement? What is the movement without the scientific heavyweights?

        • I guess I didn’t make meself clear enough, I’m not saying that Taubes is right because he wrote two heavily footnoted books. I’m saying that he offered a testable hypothesis that can be proven or disproven. To me, so far it hasn’t been disproven. Opinions, and interpretation of science by bloggers (Harris, Masterhojn, Guyenet is not enough to disprove a 150-hundred-year-old hypothesis that “carbohadrates make you fat”. This has also been the experience of so many physicians in their everyday practice over the course of tme. Of course not everybody gets fat eating carbohydrate, as is shown by the Kitavans, for instance. But no theory explains everything. If insulin theory theory should be viewed as worthless, then we must admit the food reward theory is even more so, which is not what I think.

          As for criticism Taubes’ books recieve I believe this is very little wonder is it? We have been led to believe by scientific establishment that all that matters is calories, and thus only fat can make you fat. Please bear in mind that this has also been backed up by science.

          This is not about any movement or who leads it. If it was, then it would no longer be a scientific issue but rather a socialogical or even political one. In this case one might say that Harris or Guyenet are using science only to replace Taubes as new gurus and leaders of the movement. Hope this is just about science.

          • Ansgarr ,

            What would it take in your mind to disprove the Carbohydrate Hypothesis? I believe quite a few people have reported fat gain on ZC or VLC. Quite a high percentage of the world’s population eating pre-industrial diets (1 billion or so Chinese, for example), not just the Kitavans, ate diets high in starch.

            Taubes theory of “carbs -> insulin -> obesity” is just not supported by the evidence, let alone the biochemistry. Taubes’ theory is much more than “carbohydrates make us fat;” he spelled out the biochemistry of why he believes this to be. The biochemists say he is wrong, and the evidence says he is wrong. Fructose doesn’t even cause “insulin spikes”.

            If a culture eats a “fast carb” like white rice without any problem, then switches to an industrial diet and then does see obesity and diseases of civilization, I believe it makes a whole lot more sense to look at what is it about industrial diets causing this instead of worrying about demonizing entire classes of macronutrients. The Carbohydrate Hypothesis just doesn’t work for this.

            Just because physicians use low-carb diets for weight-loss does not mean that carbs caused the weight gain to begin. Low fat diets are usually just as successful at weight loss.

            All this talk about low-carb diets being best for weight loss or best for people with “broken metabolisms” or best for whatever does not mean that “carbs” made you fat. The fact that refined wheat and sugar are bad does not mean that “carbs” are bad. But many within the guru’s influence will say “See, carbs are bad! Look at all this evidence. Taubes must be right.”

            It has nothing to do with replacing one guru with another; it is about guruism vs science. With all that is arrayed against it, there is just really no reason other than guruism to defend Taubes’ Carbohydrate Hypothesis.

            • “What would it take in your mind to disprove the Carbohydrate Hypothesis?”

              Well to me it’s quite simple.

              Let me start by saying that giving observations of healthy high-carb populations is not enough to refute a low-carb hypothesis. Why? Because correlation is not causation. As dr. Eades pointed out, the Japanese smoke much more than Americans and yet they have a much longer life expenctancy. Does it mean that we should all start smoking to live longer lives? Plus we do not know what would be, if the high-carb healthy people lived a low carb life. Maybe they would be even healthier? Or not. We simply do not know that.

              What we need is a prolonged controlled clinical trial comparing LC vs. HC (all other fatcors being controlled) showing that low carb causes more weight gain and disease than HC (even when composed of healthy unprocessed carbs). Not so sure such a study can ever be conducted for obvious reasons.

              • Ansgarr,

                It is more than just “healthy high-carb populations” and correlations. It is that “healthy high-carb populations” are fine until the introduction of an industrial diet. Industrial diet is clearly the problem. The “healthy high-carb populations” simply show that “carbs” are not the problem with industrial diets.

                • I don’t think it follows that healthy high carb populations show that ‘carbs’ are not the problem in industrial populations. One population might be adapted to high carbs, the latter might not.

                  Similarly, different age groups could respond differently to carbs. Michael Rose claims that people from populations with a long history of grain cultivation, such as those in the middle east and India, can metabolize grains well up to the age of about 30. After that their health deteriorates if they eat grain and dairy. The basis for the idea is that there are 10,000 years of selective pressure on people of breeding age to adapt to grains and dairy, whereas at the post breeding age there is no such adaption. The claim is interesting. Indians do not have an industrial diet. However potbellies are rife in middle age and diabetes is rampant.

                • “It is that “healthy high-carb populations” are fine until the introduction of an industrial diet.”

                  If my memory serves me correctly, Taubes has described populations on a non-industrial high carb diet that are obese and sick. So we have healthy “high unprocessed carb” populations, unheatlhy “high unprocessed carb” populations, we also have “healthy high-fat unprocessed-food” populations but do we have unhealthy “low-carb high-fat unprocessed-food” populations? Then again these are just observations, good for hypothesizing, not much more.

                • Gregory,

                  The issue is though that if you have a culture that is apparently “adapted” to carbs, THEN experience problems AFTER the introduction an industrial diet, it would seem to point at the industrial diet being the problem, especially when the industrial diet seems to be the common meme in most cultures, “carb-adapted” or not.


                  Other people have noted how some of Taubes’ own example populations actually dispute his own claims – the Pima Indians for example (

                  It appears that the majority of populations and people experience problems after the introduction of industrial diets, even the ones that are “carb-adapted”. You are correct that this doesn’t strictly disprove the Carbohydrate Hypothesis, but it is kind of a body-blow to its viability.

                  The common sense reaction might be to work on different hypotheses that don’t already have so much weight against it, especially when the claimed biochemical mechanisms are so strongly disputed as well. It just appears that the demonization of an entire class of macronutrients is not the way forward.

  6. Initially – awesome post. I love dietary ideologies that defy dogma.

    In regards to Jason’s Inquiry “Are there any cultures that become obese without a large intake in added sugars and/or wheat?”

    Well, can’t address the degree of wheat consumption, but a look at ancient goddess imagery shows that what we’d now term “obese” isn’t solely the result of refined sugars/carbs. An example:

    “The Venus of Willendorf, also known as the Woman of Willendorf, is an 11 cm (4.3 in) high statuette of a female figure estimated to have been made between 24,000 and 22,000 BCE. It was discovered in 1908 by archaeologist Josef Szombathy at a paleolithic site near Willendorf, a village in Lower Austria near the city of Krems.[1] It is carved from an oolitic limestone that is not local to the area, and tinted with red ochre.”

    • The Venus of Willendorf was a symbol of fertility and meant to portray a very fertile and pregnant women. Not obese.

      • perhaps. though i’m not sure we can read the mind of the artist so many years later. frankly, too me she looks obese, not pregnant. that being said even if they weren’t eating wheat, sugar, and other process foods, that doesn’t mean some of our ancestors might not have been obese. metabolic derangements are not necessarily dependent on poor diet, just more likely, no?

      • i never realized the internet was so loaded with ‘fertility-symbols’ than ;p

        i agree with bonita that we will probably never know the artist’s intent for sure.
        but the idea of these things as fertility-symbols seems to have had more to do with feminist ideas and political correctness than with rigorous scientific research. and now that feminist extremism is going out of fashion scientists finally dare to come up with alternative explanation in the vein of ‘maybe they just thought she looked totes hot’

        but regardless of it’s interpretation, it’s one of those things that flies directly in the face of everyone claiming obesity is a purely modern occurrence, a symptom of how far we have strayed from our cavemen roots.
        the woman depicted is clearly what we would now consider to be ‘overweight’ (she has fat legs and an enormous butt, so it’s not just pregnancy), and it stands to reason to assume the figure was based on women the artist would have seen around him.

  7. It’s hard to see every bubble on the chart, but I did notice “female employement.” I’m assuming that you mean outside the home?

    This should be changed to mention the lack of involvement on the part of fathers in food prep when mothers work full time. If it’s on there, please correct me.

  8. Chris –

    Nice post. A few things:

    First, no one says a high carb diet is the issue – Taubes, Eades, etc. all state that it is a diet high in refined carbs. No one thinks a diet high in leafy, cruciferous veggies and seasonal fruits will make you fat. No one who knows what they are talking about anyway.

    And just because you can observe lean people who eat lots of carbs does NOT mean that it is not the carbs that fattens some people. You will also NEVER observe an obese person who has lived his life eating only fatty meats, vegetables and some fruit.

    Sometimes we DO have the right answers. And when we have them, we should use them.

    Here is my question to you – if you had an obese patient/client, how would you have them eat? I’ll bet you’d suggest them to remove all refined foods to keep carbs to a minimum. You certainly would not suggest they eat most of their calories from carbohydrates, right?

    A low carb real food diet takes care of the insulin issue. It takes care of the leptin issue as well almost always. In fact, it takes care of systemic inflammation, obesity, toxicity and a host of other ills caused by a high refined carb, western type diet. As you know better than I do a diet that provides an adequate amount of fat and protein is by default a low carb diet.

    • “And just because you can observe lean people who eat lots of carbs does NOT mean that it is not the carbs that fattens some people. You will also NEVER observe an obese person who has lived his life eating only fatty meats, vegetables and some fruit.”

      Deserves a comment.

    • Of course if you’ve been eating an industrial diet your whole life you may not be able to deal with the amount of carbs that would be ‘normal’ and well tolerated in people raised in a different environment. I tell people I’m not on a low carb diet, I’m making up for all the boxes of Capt. Crunch I ate as a kid. My averages still aren’t that low.

    • Conversely you will not see an obese person who eats an ultra low fat, high carb diet (mcdougall, ornish etc). This diet also solves diabetes and insulin issues believe it or not and has also been shown in clinical trials to reverse atherosclerosis. It is when I discovered this that I realised just how complex obesity actually is. Obesity and disease seems to lie in the high refined carb plus high fat area which is why in isolation, carbs and fats in isolation have nothing to do with obesity.

  9. This is a great article and do I appreciate all you do. However, I really wish you had resisted the cliche of the photo of the headless morbidly obese woman. Obese people have heads and no particular reason to be ashamed of them! Also, the average obese person is quite a bit smaller than this individual.

    • I understand where you’re coming from. In almost every other article I’ve written on obesity, I’ve used a picture of a man in sensitivity to that stereotype. Unfortunately, most pictures on stock photography people of obese people follow this convention.

      • I really enjoyed this article and agree that obesity is extremely complex. It’s foolish to think we have all the answers. However, I was glad to see Masha’s comment. I was definitely annoyed by that picture. It has little to do with whether it’s a man or a woman. Fat people are people, and depicting them in such a dehumanizing way is pretty offensive. It’s a small thing but emblematic of the problem many of us (“the obese”) face: we constantly are confronted with information about how the solve the problem by people who do not share the stigma. I love your site and didn’t expect it here. Just something to think about!

    • Chris, as an overweight double amputee with no feet, I find your new photo very insensitive and inappropriate. Please change it to something else.

  10. Hi Chris, I agree with the content of your article. It’s not only one cause, but nutricionally speaking with have now many clues to discern what is and what is not helpful to loose weight.

    This said, I lost weight, when I began to adress the emotional issue. I didn’t eat much, far less than now, mostly salads, with some protein, some fruit, no fat. Sometimes I skipped meals, not because I wanted to loose wait, but because I forgot. But was really overweight, still I have weight to loose. But it was when I stopped and took time to apply my own coaching techniques, to my weight problem when I began to loose weight, naturally, eating actually more.

    After that I discovered the low-fat diet, and I follow it and enjoy its benefits. Thank you for this always interesting information, and ¡congratulations!

  11. I prefer to think of the revival of LC, the beginning of the undoing of the institutional demonization of SFAs by Atkins, and the demolishing of the diet-heart hypothesis by Taubes to be steps in a process, like Copernicus’, and Newton’s to our current understanding of physics and astronomy. Were they 100% correct? No. But they were continuing steps on a road that will be traveled as long as humanity exists.

    I don’t think the intellectual rigor problem has anything to do with Karl Popper who was a raging pompous hypocrite in this regard. What can I say, I’m not a Popper fan. I think it has to do more with a science being disassociated from reality by things like politicized institutional funding bias and a deeply flawed peer review system. Richard Feynman, who actually accomplished a hell of a lot in the advancement of science had more interesting thoughts on this subject.

    I’m deeply skeptical of the food reward hypothesis, but then I’m deeply skeptical in general. The problem I have is that it is simply too malleable and generic. Great hypotheses make testable predictions, that is the ultimate test of intellectual rigor.

    • Sean: I’m no Popper fan-boy, and I agree he went off the rails. I do appreciate the idea of researchers trying to poke holes in their own theories.

      I’m also in full agreement with the idea that politics, economics and groupthink are as much or more to blame than a lack of intellectual rigor. They’re not mutually exclusive; political and economic motivations, as well as fear of being ostracized from the in-group, can often cause a lack of intellectual rigor.

  12. The thing is, it isn’t just American people that are getting fat: draw a chart of their car size , home size, military budget size, size of wall-street profits, total US borrowing…
    to imagine that these are not all interconnected would be a real mistake

    • The chart you mention will of course show all of the numbers going up, but what about personal energy expenditure? i.e. exercise. Most of us sit at a computer all day, to earn the money to buy the food which appears magically on the shelves of the supermarket. We don’t even get out of the recliner chair to change the channel on the TV any more.

      • Jill,

        That’s a reasonable assumption, and certainly physical activity plays a role, but there are traditional cultures that aren’t particularly active and still are not obese as we are. Also, exercise has repeatedly been shown to be ineffective for weight loss.

        • Are there studies that prove that exercise has repeatedly been shown to be ineffective for weight loss? From personal exeperience, I would agree. I exercise regularly, but remain overweight but that seems to fly in the face of popular belief. There are definitely a lot of benefits and few negatives to physical activity but I find it hard to believe that it’s ineffective for weight loss.

          BTW, this is posted in the spirit of trying to understand, rather than a criticism.

          • @jill
            the idea that exercise alone often doesn’t do much to help you lose weight (and can even make you heavier, by making you more hungry after rigorous training sessions) seems to have more or less become the accepted medical doctrine nowadays.
            which is indeed a change from the past, when exercise was often touted as *the* way to shed weight, which than in turn would reduce risk of several diseases.

            btw: i should point out that even if exercise does not make you lose weight it is still general consensus that it will make you more healthy (less risk of heart-attacks and such).
            medical theory seems to be moving to a point where not keeping fit is the main source of risk, rather than fatness as such (with fatness just being an indication that you might not be very active)

  13. Any idea where steroid weight gain fits? I was not overweight before steroids, and haven’t gained any weight since. Eight years later, I still can’t lose the 30 lbs I gained while taking them.

      • If that’s the case, is there a ‘fix’ and if so what is it? Everyone I know who gained weight on steroids is still carrying it around.

        • I was a skinny child and diagnosed with asthma around 3-4 years old. My pediatrician put me on Prednisone every time I had an attack. By the time I started kindergarden I was chubby and I’ve been fat ever since. This continued until I was 12 years old and found out that most other children taking Prednisone had weight trouble also. I refused to take it after that. I’ve always been fat, never been able to kick the weight and keep it off.

          • @Bryan
            Prednisone causes salt sensitivity and consequent fluid retention. Most of the excess weight you gained is water weight. You lose much of this excess water by seriously reducing your intake of salt and salty food. You will lose weight fast, easily and safely. But you will need to remain on a low salt regimen permanently.

            Eating plenty of potassium-rich foods like vegetables and fruit will accelerate the loss of the excess fluid because potassium displaces some of the sodium from your body.

            Salt sensitivity tends to deplete the body of calcium, and calcium insufficiency leads to some fat retention that would not otherwise occur. – Increasing your calcium intake, preferably from healthy dairy like yogurt – results in extra fat excretion via the faeces so this too helps with the weight loss you seek.

          • @Bryan
            Prednisone is one of the many prescription drugs that cause sodium and water retention and lead to salt sensitivity. If you seriously reduce your intake of salt and salty food you will easily shed much of this excess fluid by way of urine. So you will lose weight fast, easily and safely. But you will need to make low salt eating a permanent feature of your life.

            Potassium displaces sodium in the body so if you eat plenty of vegetables (unsalted) and fruit this will speed up the weight loss.

            Salt sensitivity depletes the body of calcium and this leads to some fat retention, because with insufficient calcium the body cannot excrete fat properly. If you eat good dairy yogurt to increase your calcium intake you will then excrete more fat in the faeces. – See

            Good luck!

    • A nice piece of epistemology. Perhaps the “Healthy Skeptic” rubric should not be abandoned.

      Russ Farris, The Potbelly Syndrome, has a few interesting concepts: weight and appetite setpoints.

      • Hmmm, I meant to put that comment at the end, as a general observation.

        In reply to Ivy, take a look at Russ Farris’s book, cited above. He claims that excess cortisol is a common cause of potbellies (Chapter 11).

        • When I was taking the steroids, my weight gain was in the typical steroid pattern. Over the years it has rearranged itself, but stayed with me. My cortisol levels were very low for a while, but now are within ‘normal’ range, albeit low-normal.

          I will look into that book. Thanks.

    • @ivy

      Like you, I gained a great deal of weight as a result of taking prescribed steroids. Years into the problem I stumbled onto the explanation and also the best ways to reduce that drug-induced weight gain. The drugs you and I took caused sodium and water retention, and this fluid retention is the main constituent of the excess weight. If you seriously reduce your intake of salt and salty food you will lose weight easily, safely, fast and effectively, but you will need to make low salt intake a permanent feature of your life.

      Salt sensitivity also causes the body to become depleted of calcium and this in turn causes some fat retention and this too contributes to the weight gain. If you increase your intake of dairy calcium this results in more fat being excreted in the faeces and so helps with the losing of some of the excess weight. (See

      Furthermore, if you eat plenty of unsalted vegetables and fruit your weight loss will be speeded up because these foods are rich in potassium, and potassium tends to displace sodium from the body.

      My website contains much more detail about obesity and the salt connection, and does not sell or advertise anything. I hope you will visit it and benefit from the information there.

  14. Chris,

    This is a great article and long overdue concept. However, I have one question and would appreciate your opinion.

    Are there any cultures that become obese without a large intake in added sugars and/or wheat?

    It seems to me that sugar and flour are the required “ingredients” no matter what the underlying cause is.



    • Jason: that’s a good question. I can’t think of a culture that became come obese without processed sugar and flour. I’ll ask Stephan, and if anyone else has an example please chime in. But even if we can say they are pre-requisites (as I argued when I said the “modern lifestyle” is a pre-requisite to any of the prevailing theories like food-reward), it’s obviously not the whole story because there are plenty of people that eat sugar and wheat that don’t get fat.

      • It makes me think of allergies. Dogs don’t cause allergies, but the presence of a dog triggers allergic reactions in some people.

      • True, but if there has never been a culture that has gotten fat without sugar and flour, wouldn’t we know how to avoid getting fat? We might not know the whole picture, but we know a necessary component. You can say to someone, “you might not get fat if you eat flour and sugar, but you will definitely not get fat if you don’t eat them.”

        • This is where genes and epigenetic mechanisms come to play. Take a band of hunter gatherers or traditional horticulturalist foragers (e.g., Pima, Inuit, Pacific Islanders). The band is made up of individuals with allelic variation that contributes to variation to obesity (or any given disease phenotype). On their ancestral diet this variation is not expressed; that is, it is latent. But put on a Western diet, especially industrially derived with refined sugar and flour, and those individuals with the “fat” variant (for lack of a more precise term) are the ones who get fat on this diet. The underlying genetic variation that was latent on the ancestral diet is now expressed on the industrial diet. This framework applies to many modern diseases that occur in a probabilistic manner within a population.

      • Obesity per se is probably the wrong focus, i.e. there are people who eat wheat and sugar and don’t get fat, but at least some of those people develop other aspects of metabolic syndrome. Focusing on fat probably draws us away from the deeper issue. In the big picture (and depending on how you define it), obesity is “caused” by some failure in metabolic regulation. Perhaps the relevant question is the cause of metabolic dysfunction, whether it makes you fat or not.

        • Ah but its easier to focus on obesity because it’s a visual representation of the metabolic dysfunction!

        • Agreed! Cause > Mechanism > Effect (the change wrought via the ‘mechanism’ initiated by the ’cause’) > Symptom (any one of the visible/measurable manifestations of the ‘effect’)!

          As Charles Washington (of Zeroing In On Health) often says: “only the lucky ones get fat”!

    • They are some interesting cases of of native population where obesity is prized. They do manage to get fat(ter) without bread, through the consumption of massive quantities of calories. The process appears to be difficult, unpleasant and the results don’t last. I’m not aware of any non-modern population where gaining weight is accidental, unwelcome and difficult to reverse.