The science of obesity: what do we really know about what makes us fat? An essay by Gary Taubes

BMJ 2013; 346 doi: (Published 16 April 2013)
Cite this as: BMJ 2013;346:f1050

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I wanted to further comment on the misuse and erroneous extrapolations made about the first law of thermodynamics. Doctors are notoriously guilty of this.

First, there isn't anything about a law that makes it any "more true" than a theory. laws are NOT immutable. They CAN be wrong. They CAN be changed just as easily as a theory given new evidence, realization of past mistakes or new gained perspectives.This does NOT mean the said law in question is NECESSARILY wrong, though.

My point is - there is no hierarchy. This is a common mistake.

Now, I am not suggesting the first law is wrong. It is very useful.It's valid.

Laws , in science, have a very limited reach. They give us "the what". They are descriptions of nature's behavior. Also in many cases they only work under certain circumstances. Many laws are "true" under certain circumstances and "false" under others. (e.g. Did you know the laws of thermodynamics completely fall apart when we enter the event horizon of a Balck Hole?).

The first law does NOT say that "we had to have EATEN more than we burned." It does NOT imply ANYTHING about personal behaviors- eating exercising or otherwise. In fact, you can NEVER tell just by looking at an obese person what their habits are. There are plenty of who eat reasonably and exercise a lot.

On the exercise note- research from Dr. Stephen Phinney shows that overexercising aerobically for more than about an hour actually can DECREASE the resting metabolic rate).

There are plenty of fat people who eat LESS than naturally thin or normal weight people, YET continue to gain or can't budge a certain weight. A person naturally 150 pounds (who never dieted and always was this weight) can eat considerably more than a formerly obese weight reduced person of the same weight. Dr. Liebel has shown that the body responds to a loss of 10 % of body mass by reducing totasl energy expenditure by 25% ! Add to this a chemo-mechanic efficiency that is induced and this effects persist the rest of your life.

Add to this that GUT microflora has a central role in energy balance. Many obese people have unfortyunate gut microbiota compared to thin people. The strains can be radically different etc. The first law says NOTHING about this, nor was it meant to.

The first law also does NOT say that "eat less , move more" works.

Those are ALL EXTRAPOLATIONS. It is silent on those matters and never was intended to address them.

ALL the first law says is that IF a person gained mass then this person had to have had a consistent positive energy balance over a period of time
* S-O-M-E-H-O-W * That's it. That is the extent of its scope and reach.

Using the first law of thermodynamics to justify blaming and berating obese people is as scientifically erroneous as erroneous can be.

Lastly, I am in contact with several TOP experts on non-equilibirum thermodynamics. They ALL have told me that " the loss and gain of body fat/muscle are extremely complex BIOCHEMICAL processes best understood within that framework RATHER than basic physics."

The human body is an open, NON- equilibrium dissipative thermodynamic system. Humans produce a lot of lost energy in the form of dissipated heat.

I really hope medical doctors will start EDUCATING themselves about the extremely LIMITED scope and reach of the first law of thermodynamics.They are notorious for having a phony understanding of it and blaming VICTIMS of obesity.

As world renowned obesity researcher, Dr. Jeffrey Friedman, has said "Blaming obese people for their obesity makes no sense whatsoever scientifically."

Yes, it is valid for life, but it says NOTHING WHATSOEVER about obesity- NOTHING about WHY we became obese ( i.e. the many causes).

Let us never mention it again. It is POINTLESS. gary Taubes is 100 % correct.

Competing interests: None declared

R Razwell, Tropical Biologist

University Of The Amazon, Ala Moana Blvd

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Nobody can get fat unless they eat more than they consume.

Today we (in western societes) eat far more than we need but most stay reasonably slim.

There is a growing (excuse the pun) number of fat people (obese).

Some are due to over eating but most can be considered an illness condition.

We put hormones into the agricultural system to speed up animal growth.

We GMO plants/animals to make them grow faster amongst other things.

We use more and more sugar replacements to fool our insulin system. eg aspartame

Antibiotics come in our food and even drinking water (eg fluorides (an antiseptic) and recycled drugs).

Any of the above and more are almost certain to be playing their part in the unacceptable number of obese persons and those with diabetes or pre-clinical signs.

Refined sugar has been around for hundreds of years and probably plays an unimportant role in this new illness condition.

France had virtually no obesity problem a few years ago.

Today with rampant and growing use of sugar substitutes or artificially made attempts to mimic honey together with forced direct or indirect ingestion of GMO foods from the Americas, France is fast becoming a mimic of the obesity and other maladies in USA.

This problem is extremely serious for those obese and a dire warning for the rest of us that not all is right and correct in our food and drink.

Competing interests: None declared

John C Fryer, Retired Chemist

independent, France

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16 May 2013

The article by Gary Taubes (BMJ 2013 ; 346 : 16-19) focused on the current concept of 'energy balance' (or 'imbalance') and the endocrine hypotheses to account for the present epidemic of obesity. That ignored the possibility of a dietary component 'foreign' (or at high concentration, or both) as far as the mammalian kingdom is concerned, as being responsible.

This reminded me of some work carried out in the 1960s. Refined sucrose (at high concentration) is totally alien historically to Homo sapiens; although fructose has existed in the day-to-day diet since time immemorial, it is only relatively recently that that has attained anything like the high level which exists today. The fructose moiety of sucrose is metabolised in an entirely different manner to that of its glucose component1; it does not stimulate insulin release but raises blood concentrations of lactate and pyruvate whether presented to the enterocyte in its mono- or disaccharide form.2,3 It also seems possible that it influences triglyceride deposition in both liver and adipose tissue. Furthermore, there is evidence of a widespread variability in its breakdown products.4

Surely the time is ripe therefore, to learn more about the metabolic products of a highly concentrated sucrose (and hence fructose) intake, rather than attempt resuscitation of old hypotheses. It is also time to substantially reduce the dietary intake of sucrose and to monitor the effect on its deposition in adipose tissue and subsequently body-weight.

1 Cook G C. Absorption products of D(-) fructose in man. Clin Sci 1969 ; 37 : 675-87.

2 Cook G C. Comparison of the absorption and metabolic products of sucrose and its monosaccharides in man. Clin Sci 1970 ; 38 : 687-97.

3 Cook G C. Absorption and metabolism of D(-) fructose in man. Am J clin Nutr 1971 ; 24 : 1302-7.

4 Cook G C, Jacobson J. Individual variation in fructose metabolism in man. Br J Nutr 1971 ; 26 : 187-95.

Competing interests: None declared

Gordon C Cook, Retired Tropical Physician

University College Hospital, St Albans, AL1

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In 1974, Dr. Cottrell’s World Sugar Research Organization (then the International Sugar Research Foundation) hosted a conference to discuss the evidence linking sugar to obesity and diabetes. The organization then disseminated a memo in which its own scientist-consultant stated that a “well-designed research program” was necessary to elucidate sugar’s role in these disorders and “should be undertaken in a sufficiently comprehensive way as to produce results. A gesture rather than full support is unlikely to produce the sought-after answers. (1)” Since the Nutrition Science Initiative is trying to do just that with independent, unbiased researchers, I would hope that the WSRO would give its full support.

Dr. Cottrell cites a WRSO report claiming that world caloric sweetener consumption has been static for decades. These data are difficult to reconcile with International Sugar Organization reports that world sugar consumption rose between 2001 and 2011, for instance, by an average of 2.2 percent yearly, nearly twice the population growth rate (2).

Such trends can neither confirm nor refute the hormonal/regulatory defect hypothesis or sugar’s role in obesity. Dr. Cottrell assumes incorrectly that caloric sweetener consumption must increase to explain the obesity epidemic. If a threshold effect is at work, then prevalence can increase so long as sugar consumption is above that threshold. This is another argument for well-controlled experiments to establish causality.

Dr. Cottrell claims that insulin levels remain low in healthy individuals, but the study he cites reports a long-term deterioration of insulin sensitivity in this population (3). The accompanying editorial suggests that "this is doubtless the effect of progressive inactivity and middle-age spread.” It could just as likely be the effect of a dietary trigger of “progressive inactivity and middle-age spread (4).” Such observations can't differentiate.

Dr. Cottrell suggests that the hormonal/regulatory defect hypothesis is incorrect because de novo lipogenesis is low during carbohydrate overfeeding, a common misconception. As the reference Cottrell cites says, body fat stores can be increased “not by conversion of the carbohydrate to fat. Instead, the oxidation of dietary fat [is] suppressed and fat storage thereby increased. (5)"

Despite our disagreements, it’s critical to remember that this discussion is about real people, their health and quality of life. Based on what the last 50 years has shown us, we need new information and better science, because the conventional wisdom isn’t working. Our friends, family and neighbors are afflicted with a spectrum of metabolic disorders; it is incumbent upon us to challenge conventional thinking when it appears so clearly to be failing.

1. Taubes G, Couzens CK. Sweet Little Lies. Mother Jones 2012;November/December:34-40,68-9.

2. International Sugar Organization. Quarterly Market Outlook. International Sugar Organization 2011;November.

3. Tabak AG, Jokela M, Akbaraly TN, et al. Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study. Lancet 2009;373:2215-2221.

4. Matthews DR, Levy JC. Impending type 2 diabetes. Lancet 2009;373:2178-9.

5. Hellerstein MK. No common energy currency: de novo lipogenesis as the road less travelled. American Journal of Clinical Nutrition 2001;74:707-8.

Competing interests: None declared

Gary A Taubes, Journalist

Nutrition Science Initiative, 6020 Cornerstone Ct. W. San Diego, CA 92121

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I've just noticed a vital typo on my previous rapid response. I said 5ml of petrol will take a car 5km, and I should have said 500ml!

Competing interests: None declared

Laurence Wood, Obstetrician

Berega Hospital, Tanzania, 6 Dalton Road

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Readers of this article and some of the respondents might be interested in an article published in 2004 in the Int. Journal of Sport Nutrition and Exercise Metabolism 14:709-199 2004. It may not be applicable to all groups but is nonetheless interesting and pertinent to the discussion about energy balance, food type and obesity.
The study looked at the dietary intake of Kenyan long distance runners. The average height of these runners was 5'9" and the average weight was 129 lbs, quite lean by any standard. Carbohydrates contributed 76.5 percent of the daily energy intake, 13.4 percent was from fat. Of the carbohydrates, ugali, a corn based product, contributed 23 percent of the total calories. Simple sugar contributed 20 percent of all calories (534 calories a day) and rice contributed 14 percent. The athletes ate 5 times a day and quantities were unlimited. Meat was eaten 4 times a week in small quantities.

Of course, they also ran about 75 miles a week with about 1/3 of this at a very fast pace.

Competing interests: None declared

David P Slaughter, physician

NA, Clancy Mt

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Diet and weight gain (and weight loss) are not under voluntary control, of that there is no shadow of doubt, no possible probable shadow of doubt whatever.

The same cannot be said for exercise.

Self starvation results in persistent suffering. Exercise in a greater sense of well being.

Is it time to consider the war on obesity over, and lost? Should we instead focus upon creating opportunities for people to do what their bodies were designed to do? (To move.)

Competing interests: None declared

Stephen R Workman, MD

Dalhousie University, QEII HSC Halifax NS Canada

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Dear Sir,

For most cases of obesity, why can’t we simply say that obesity is a manifest discrepancy between total energy intakes versus the energy output? Wouldn’t this simple statement be appropriate in about 90 to 95 percent of cases of obesity? Lifestyle factors, and excess energy intake, vis-à-vis reduced energy expenditure are at play here in this major chunk of nearly 90 to 95 percent. It is just a miniscule of percentage that some of the other causes for obesity can actually be traced, like genes, metabolic and hormonal causes, etc.

Let us start by relating the first author’s own personal inch and pound story. All the times that he was sent on postings to some real difficult areas, arctic climates, hot-spots so as to say, for months and years together, his weight remained well within the laid down parameters, like almost everyone who were with him along sides. Those were the times when he was away from his family, took all the entitled calories and then some more as well, never really counting the calories. Like all others out there posted with him, as he says, he too was missing his family and was slightly concerned for their welfare while they were separated from him owing to his posting to very difficult areas. But then, he did use to return to the base after two and a half to three years, and it did not take him more than six months to start getting counted in the overweight or obese category, although every other possible factor had remained quite unchanged. This cycle was repeated many a times with him, and we did raise this concern earlier on as well [1, 2]. Call it whatever you may, mental peace, tranquility, mood, familiar and congenial surroundings, being in the company of the family once again, etc.

These cycles of his postings to estranged and very difficult areas affected his wife and his children in almost a similar pattern; turning slim when he was away, and picking up weight as soon as he was back, although all that while they had kept staying at a far off secure places with other families, and there was daily cooking of delicious and savory food, with more than enough calories. We believe that this peculiar trend would have been observed by all veterans from around the world, and of any country, and that they would easily understand and acknowledge, notwithstanding the difference in beret, or whatever emblem or insignia they might have been sworn to.

We believe that mood, temperament, congenial and relaxed environment, cooking and eating habits, do have a strong role to play, besides physical inactivity, and other indulgences that have already been identified elsewhere. As per his own reasoning, the reasons for him catching on weight are not too many. It is just one perhaps, and that is that he turns lazy, from the very moment he used to get back home and rejoin the congenial environment of his family.

We do have some latest management techniques for obesity, like the anti-obesity pills, liposuction, bariatric surgery, etc. Recently, we have developed a fairly new technique to remove unwanted flab from the waist, thighs, arms, etc. This is a totally painless technique, non-invasive, and we are able to decrease waist by three inch in a matter of three days. We would want this technique be called “Dr. S. Arulrhaj’s non-invasive technique for flab and cellulite removal” [FIGURE 1], as he has always been a revered teacher and a mentor. This technique uses an interplay of various electro-medical appliances in varying combinations and proportions, depending on the problem, its extent, duration, and severity. We could do just this much at our own, with our own initiative, own accord, own resources, and without any help or encouragement from any non-governmental or governmental source, national or international. Alongside we have also been prescribing, empirically though, a short course of aspirin and anti-cholesterol agents in minimal doses for just about a week. We do feel that much more research needs to be done, to make this technique more viable, acceptable, more precise, with improved accuracy, safety, acceptability, and making it totally free from any untoward results or complications. We had presented this latest technique threadbare to the august gathering of doctors, along with many other new techniques, at the III International Congress of Family Medicine and the ICON 2012, that were held at Chennai, India, in September 2012. A gist was also presented at the Commonwealth Medical Association’s Annual Conference that was held at Chennai, India, on the same dates and at the same venue where the other conferences were held.

Best regards.

Dr (Lt Col) Rajesh Chauhan
Hon’ National Professor (IMA CGP), INDIA

Dr. Ajay Kumar Singh Parihar
Resident, Dept of Medicine, Index Medical College, Indore. INDIA.

Dr. Shruti Chauhan


1. Chauhan R, Chauhan S, Chauhan S, Chauhan SPS. Obesity: the new "raja" or just fetal origins? BMJ 14 June 2005. (Accessed on 09 May 2013)

2. Chauhan R, Chauhan S, Chauhan S, Chauhan SPS, Chauhan A, Chauhan A. Obesity - an ongoing controversy. BMJ 12 Dec 2005. (Accessed on 09 May 2013)

Competing interests: None declared

Dr (Lt Col) Rajesh Chauhan, Consultant Family Health

Dr. Ajay Kumar Singh Parihar, Dr. Shruti Chauhan.

Family Healthcare Centre, 154 Sector 6-B, Awas Vikas Colony, Sikandra, AGRA. INDIA., 154 Sector 6_b, Awas Vikas Colony, Sikandra, AGRA. INDIA. PIn : 282007

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Well done Dr Taubes! Many decades after Judkin set out convincing arguments about the dangers of sugar (and high GI carbs), at last it is no longer quirky to believe it.

Two points need to be made, however, to complete the picture. Firstly, perhaps only one third of the population have the 'bad fat & excess insulin’ genes in sufficient penetration to make them predisposed to truncal obesity. These people, broadly speaking, can be recognised by having a waist-height ratio of >50%. (Perhaps, genetically, they are hunter-gatherers: If your ancestors herded on a hillside and your belt is tight, watch the carbs!)

A second and vital point to complete the thermodynamic picture is the idea that not all consumed energy turns to flesh! Thin people burn off energy as heat, which is hugely more wasteful of calories than trying to burn it off as exercise. As a result, they stay thin. 5 ml of petrol will take 500kg of car 5km. The same amount flung onto a fire produces a grand flash - and then it’s gone.

Vitally, sugar ingestion in the predisposed, not only starts a process whereby the fat effectively 'sucks in' calories, but also at the same time, switches off the metabolic burners. It is this final failure to burn off the calories as energy which allows obesity to remain.

Competing interests: None declared

Laurence Wood, Obstetrician

Berega Hospital, Tanzania, 6 Dalton Road

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Most people are grossly misinformed on this topic. The human body is an open and NON- equilibrium system. This makes the situation hellishly complex.This is a very SUBTLE area of thermodynamics.

Scientists do not at all understand the chemical behavior of fat cell receptors. The unknowns about obesity are enormous. They are far greater than any knowns.

Invoking "thermodynamics" in an obesity discussion is absolutely meaningless and pointless.People do NOT realize its extreme limited scope.

It does not address:

* That the body aggresively defends fat mass against loss- it fights back and undermines us.

* That the BODY is in control of energy balance- not us

* That the body has biological safeguards.

*Nor does it address hormonal situations

*Nor does thermodynamics imply ANY fault whasoever

*Nor does it able to address a person's habits. There are MANY obese people that eat well and exercise , yet remain obese.

The above points ALMOST ALWAYS get lost in this discussion.

ALL "thermodynamics" says is that IF a system gained mass it had to have a positive energy balance over a certain period of time- THAT'S IT ! That is the EXTENT.

There are MANY things that affect this energy balance INVOLUNTARILY- far beyond any conscious control.

As Dr. Rudolph Liebel said " Our research has clearly shown that with regard to body weight, the body has a MIND OF ITS OWN."

Down this road the party line doctors do NOT want to go with me. I have studied this in extreme detail every single day for the last 6 years and have spoken to about 20 biophysics scientists from Harvard, Caltech, UCLA, and elsewhere .

I support Gary Taubes 100 %. He is a meticulous researcher, creative and intelligent.


Competing interests: None declared

R. Razwell, Science

University Of The Amazon, Ala Moana Blvd

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