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Why The Energy Balance Equation Results In Flawed Approaches To Obesity Prevention And Management

1st law of thermodynamics obesityAllow me to start not with the first law of thermodynamics (energy cannot be created or destroyed) but rather, the second law of thermodynamics, according to which entropy (best thought off as a measure of disorder), in any closed system, increases till it ultimately reaches thermodynamic equilibrium (or a state of complete disorder).

As some of us may recall from basic biology, the very definition of “life”, which tends to move from a state of lesser organisation to a state of higher organisation, is that it appears to defy the second law of thermodynamics (this is often referred to as “Schroedinger’s Paradox”).

In actual fact, we can easily argue that the second law does not apply to living organisms at all because living organisms are not closed systems and life’s complex processes continuously feed on its interactions with the environment.

Yet, when we consider the first law of thermodynamics and how it applies to obesity, we seem to forget the fact that we are again dealing with a complex living organism.

Thus, in what has been referred to as the “Folk Theory of Obesity”, we simply consider weight to be a variable that is entirely dependent on the difference between energy input and energy output (or “calories in” and “calories out”). And in our arithmetical thinking, we consider “energy in” and “energy out” as simple “modifiable” or “independent” variables, which if we can change, will result in any desired body weight.

In fact, our entire “eat-less-move-more” approach to obesity is based on this concept – the central idea being, that if I can effectively move “energy in” and “energy out” in the desired directions, I can achieve whatever weight I want.

This notion is fundamentally flawed, for one simple reason: it assumes that weight is the “dependent” variable in this equation.

However, as pointed out in a delightful essay by Shamil Chandaria in my new book “Controversies in Obesity“, there is absolutely no reason to assume that weight is indeed the “dependent” or “passive” player in this equation.

Indeed, everything we know about human physiology points to the fact that it is as much (if not more) body weight itself that determines energy intake and output as vice versa.

Generally speaking, heavier people tend to eat more because they have a stronger drive to eat and/or need more calories to function – in other words, body weight itself may very much determine energy intake and output (and not just the other way around).

Similarly, losing weight tends to increase hunger and reduce energy expenditure – or in other words, changes in body weight can very much determine changes in energy intake and expenditure (and not just the other way around).

Thus, the idea that we can control our body weight by simply controlling our energy intake and output, flies in the face of the ample evidence that it is ultimately our physiology (in turn largely dependent on our body weight) that controls our energy intake and output.

Thus, to paraphrase Chandaria’s key argument, it is not so much about what “energy in” and “energy out” does to our body weight – it is more about what our body weight does to “energy in” and “energy out”.

Once we at least accept that this equation is a two-way street, rather strongly biased towards body weight (or rather “preservation of body weight”) as the key determinant of “energy in” and “energy out”, we need to ask a whole different set of questions to find solutions to the problem.

No longer do we restrict our focus to the exogenous factors that determine “calories in” or “calories out” (e.g. our food or build environments) or see these as the primary targets for decreasing caloric intake or increasing caloric output.

Rather we shift our focus to the physiological (and psychological) factors (often dependent on our body weights) that ultimately dictate how much we “choose” to eat or expend in physical activity.

Chandaria’s essay goes on to discuss the many “derangements” of physiology that we know exist in obese individuals (and probably already exist in those at risk for obesity), including leptin resistance, impaired secretion of incretins like GLP-1, insulin resistance, alterations in the hypothalamic-pituitary-adrenal (HPA axis), and sympathetic activity. (Any keen student of human physiology or psychology should have no problem further extending this list.)

In Chandaria’s view, it is these physiological (and psychological) processes that ultimately determine whether or not someone is prone to weight gain or ultimately gains weight.

In fact, the only factor that determines why two individuals living in the same (obesogenic) environment will differ in body weights (even when every known social determinant of health is exactly equal), is because of their individual physiologies (and psychologies) which ultimately determine their very own individual levels of “energy in” and “energy out” (and how their bodies respond to it).

Readers may be well aware that in tightly controlled feeding studies, the same absolute amount of extra calories can result in very different amounts of weight gain.

Similarly, the exact same amount of caloric deficit will result in widely different amounts of weight loss.

Ignoring this basic fact of human nature distracts or, at the very least, severely limits us from finding effective solutions to the problem.

This “physiological” view of the first law of thermodynamics should lead us away from simply focussing on the supposedly “exogenous” variables (“energy-in” and “energy-out”) but rather draw our attention to better understanding and addressing the biological (and psychological) factors that promote weight gain.

This would substantially change the aims and goals of our recommendations.

Thus, for e.g., rather than aiming exercise recommendations primarily at burning more calories, these should perhaps be better aimed at improving insulin sensitivity and combating stress. Thus, rather than counting how many calories were burnt on the treadmill, the focus should be on what that dose of exercise actually did to lower my insulin or stress levels.

Indeed, we may discover that there is a rather poor relationship between the amount of calories burnt with exercise and the physiological or psychological goal we are trying to achieve. While more exercise may well help burn more calories (which I can eat back in a bite or two), it may do little to further improve insulin resistance or combat stress thus leaving my weight exactly where it is.

Similarly, rather than trying to restrict caloric intake, dietary recommendations would be based on how they affect human physiology (e.g. gut hormones, reward circuitry or even gut bugs) or mood (e.g. dopamine or serotonin levels).

In other words, fix the physiology (or psychology) and “calories in” and “calories out” will hopefully fix themselves.

Given that our past efforts primarily focussing on the “energy in” and “energy out” part of the equation have led nowhere, it is perhaps time to focus our attention and efforts elsewhere.

Or, as I often say in my talks, “We’re not talking physics here – we”re talking physiology – that’s biology messing with physics”.

We cannot mess with the physics but we sure can mess with the biology.

Edmonton, AB

Shamil A. Chandaria: The Emerging Paradigm Shift in Understanding the Causes of Obesity. In Controversies in Obesity. Eds: Haslam DW, Sharma AM, Le Roux CW. Springer 2014


  1. I’m certainly not a scientist but I have written about concepts like these myself because I think cultural and social bias has put far too much emphasis on believing that if you’re fat it’s because there’s something wrong with you, you don’t have control of your emotions, you’re some kind of addict, and you need to work out psychological issues. The reality is that we are in a constant fight with our own physiology!

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  2. “Folk Theory of Obesity” – my as**, I think the medical establishment can’t get of the hook that easy by re-branding this as a “folk” theory, this was for many years and still is the official theory of the medical establishment – I know it is embarrassing, but I can prove this by any number of official documents (publication from USDA, CDC, AMA, AHA endless peer-reviewed papers etc…) and textbooks.
    Moreover disputing calories-in/out theory (the basic dogma of obesity research), usually brands you as a clown when conversing with any medical professional.

    Now trying to say as if we (the Dr’s) knew this all along, it is just that the public is simply can’t be expected to follow the intricate and complex research hence it has a distorted and over simplified view of research and invents for himself some over-simplified “folk theories”, would be a misrepresentation of the truth.

    The medicalization of dietary advice is an unmitigated disaster.

    I also saw the reference to “Folk Theory of Obesity” in the “controversies in obesity” you promoted, which again is laughable.

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    • @eil: unfortuntely, you are only too right. Far too many in the “medical establishment” have bought into and promoted this theory, which is exactly why we re where we are. Understanding the physiology and psychology of obesity is not about “medicalising” the problem – it is simply about applying good science.

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  3. @DR Sharma: I am also for good science, everybody is for good science, the question is whether this is a reasonable expectation i.e. that the “medical establishment” can provide “good science”, firstly it failed until now, it contributed to the obesity crisis, and I think it is currently the main obstacle to successfully tackling the problem. Its also seems to be setup in away that is not conducive to good science…. in any case my comment was mainly regarding the phrase “folk theory of obesity” I think it is misleading in regard to understanding the source and origin of this “theory”. It would be better and more accurately called:
    “The central dogma of obesity research and public health”.

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  4. Youch! So in conclusion:
    This equation really has very little to do with obesity and is simply an interesting aspect of the functioning of the human body to ponder and discuss, but it is however, often used incorrectly to misdirect a populace suffering with obescity.

    The problem is perspective, or the lack of clarity as to resolving the issue of obesity. Weight is not really the issue here, however the populace is often fooled into thinking that it is. Body fat percentage included in, or in excess of a person’s natural weight as a result of the choices of the person, or a condition causing this state to exist, are the real problems. Some of the real issues are;

    – the effects of social environment on the perspective of a human.
    – the percentage of body fat compared to lean muscle in the human body.
    – the overall health of an individual physically and mentally.
    – individual genetics.

    Obesity is often the result of a combination of poor food choices and lethargy that has a negative effect on the physical and psychological aspects of the individual. Determining the cause(s) that have directed the choices of the individual to this result, or creating the conditions, and applying processes to assist the person both mentally and physically to acquire a healthy state is the solution.

    A couple idioms that seem relative to the topic at hand that I enjoy;
    “An obese person is not fat, they have fat. There’s a difference.”
    “Scales are for fishes”

    Don’t be concerned with losing weight. Be concerned with losing body fat and having lean muscle. Be concerned with living comfortably in your body at your natural body weight, eating well and exercising, and being happy and healthy both physically and mentally.

    I realize that attempting to modify the equation you have discussed is also a part of the problem. It is being presented, or applied as a solution by many, and simply doesn’t work. Just thought I would put a finer point on some of the the real issues.

    We are either part of the solution by showing compassion, strength, and unyielding support for people battling with obescity, or part of the problem by supporting the “snake oil” products and methods, the unhealthy foods and perspectives that are advertised and sold by companies/people that are lacking in integrity and ethics for their own gain (no matter the cost to others) that are taking unfair advantage of a large portion of the populace that is suffering.

    Thank you for your efforts in the solution.

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  5. Hi Dr. Sharma, 🙂

    The first law of thermodynamics does not address fat cell regulation/dysregulation specifically. Nor what form of mass specifically is lost or gained . Nor does it address body composition specifically. Nor does it address energy partitioning and HOW energy is used- a central factor! Nor does it address if we ever achieve that consistent negative energy balance. Energy can be led to many, many pathways. Why Bo Jackson could put on muscle from lifting weights in a positive energy balance, while those struggling with obesity , doing a similar thing will largely gain mostly fat is not at all addressed by the conservation of energy principle .

    There is MUCH more that goes into looking like a prime Evander Holyfield than a negative energy balance. Great genes, weightlifting etc. sparring muscle. Look at these people on starving reality survival shows. They still have their saddle bags and fattier builds after starving for 20 days. There are all different body shapes. Contestant naked in the wilderness fully illustrates the failure of the oversimplified caloric hypothesis. These people lose MUSCLE largely. I have been there done that. Never again will I diet- ever. Hunger, weakness, no energy bonier shoulders, muscle loss and STILL saddle bags. No thanks…

    Prime Arnold and Bo Jackson very big lean pieces of human meat- sirloin. I have seen many people who are fatty humans like salami at small sizes. Some people are much fatter than others naturally. My brother is a professional natural bodybuilder. He eats sometimes a whole can of whip cream in about 3 hours during his visit. He is very lean and muscular. If a typical obesity sufferer did this-they’d get fatter

    The first law of thermodynamics is relevant to all life but not nearly sufficient- not by a long shot. Energy balance is only one of the things going on . There is much, much more going on – as 50 different scientists (physicists and scientists who study molecular machinery of life) I talked to from CalTech, Harvard, M.I.T. and more told me.

    Humans are open, non-equilibrium , dissipative systems. This makes the situation hellishly complex. The best scientists in the world , who specialize in this field, personally told me that while the first law is valid for life, obesity is NOT a matter of basic thermodynamics, but, rather, an extremely complex biochemical phenomenon best understood with in that framework. Yes, the first law is relevant but not nearly sufficient. Normal people cannot be Manuel Uribe no matter how hard they try.

    There is nothing in the first law that “requires” that excess calories have to be converted into fat in the absence of anything else being done. The first law would be content if we ate large chocolate bars and crapped them out again whole.

    All of these Internet gurus are scammers who are abusing/misusing and exploiting it. I have verified this over and over the last 6 years and want the Internet Blogosphere to know.

    Thanks for all of the work you do.



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