Why the first law of thermodynamics is utterly irrelevant

There are many adherents to the Calories In/ Calories Out (CICO) theory that constantly bleat about “It all comes down to the First Law of Thermodynamics”. The First Law of Thermodynamics refers to a law of physics where energy cannot be created or destroyed in a closed system and is ALWAYS true.

However, in the complex world of human physiology, it is true but completely irrelevant. What the CICO people think it means is that if you reduce calories in, you will lose weight. Of course, it means nothing of the sort.

So, let’s see why. CICO1Here’s our representation of the human body. You have Calories In, Calories Out and Fat Storage.

This is the fatal flaw of CICO – there are two compartments where calories can go after being eaten, (Calories Out and Fat), not one. It is not a one compartment problem.

CICO adherents believe you take calories in, subtract calories out and whatever is left over is dumped into fat stores like a potato into a sack. So, they believe that fat stores are essentially unregulated. Every night, like a store manager closing its books, they imagine the body counts up calories in, calories out and deposits the rest into the fat ‘bank’. Of course, nothing is further from the truth.

How the body works

So here’s the way the body works. Every process is highly regulated. Whether we burn calories as energy or whether it goes towards fat storage is tightly controlled. As we eat, calories go in. Calories go out as basal metabolism (used for vital organs, heat production, etc) and exercise. Fat can go into storage or it can go out of storage.

CICO3What controls this decision? We all agree that the main hormone involved is insulin. As we eat, insulin goes up. Notice that the body does not respond to calories equally. Some calories (white bread) will raise insulin a lot, and others (butter) will hardly raise insulin at all. This should have been the first clue that calories are not the common language of weight gain/loss. The body has no receptors for calories and has no way of measuring calories.

Consider two foods that are equal caloric values – a plate of cookies versus a salad with olive oil with salmon. As soon as you eat, the body’s metabolic response is completely different and easily measured. One will raise insulin a lot, and the other won’t. So why do we pretend like the body cares about calories.

That’s like saying that foods that are blue are the same – whether they are blueberries or blue raspberry Gatorade. The body doesn’t care about color, so why would I? In the same way, the body doesn’t give two sh**s about calories, so why should we? However, the body DOES care a lot about the hormonal response to the foods we just ate.

Since we are eating more at that moment than can be used by the body, some of this food energy gets stored away, either as glycogen or fat. This is insulin’s role. It stores food energy through the processes of glycogen synthesis and de novo lipogenesis (making of new fat in the liver).

CICO5When we stop eating, insulin starts to fall. This is the signal to first stop storing food energy. As we continue to fast (say, during the night), we need to move some of this food energy back out from our stores to power our metabolism. Otherwise, we would die during our sleep, which obviously does not happen.

OK. So far, so good. Now let’s put some numbers on it. Let’s assume we are not gaining or losing weight, but have 100 pounds of fat we’d like to drop. Assume a daily average intake of 2000 calories. This is what it will look like.CICO2

Since Calories In and Calories out are balance, and Fat is neither going up or down, everything is in balance. The body wants to burn 2000 calories to stay warm and feel good. So what happens when we decide to lose weight?

Weight loss the CICO way

The CICO people say that all you need to do is reduce your calories in. You don’t need to worry about what you are eating because ‘it all comes down to calories’. So, eating a calorie reduced, low fat, high carbohydrate diet, insulin levels stay high, but calories comes down. They do this on shows like ‘The Biggest Loser’, but this is the exact same strategies that all the universities, and governments use too.

CICO7What happens?

You reduce your intake to 1200 calories per day. Since insulin remains high, you cannot get any energy from fat stores. Why? Because the dietary strategy you are using (Caloric Reduction as Primary) only concerns itself with reducing calories, not insulin. Remember that the high insulin is telling the body to store energy as fat, or at a minimum, not burn fat (inhibits lipolysis).

So, as you reduce your caloric intake to 1200 calories in, the body is forced to reduce it’s metabolism to only 1200 calories. No energy is available anywhere else. This is precisely what happened on the Biggest Loser as seen in the study featured in the New York Times. This is also precisely what happens during any caloric reduction diet.

That is why these diets are doomed to fail. Studies of this strategy estimate failure rates at 99%. Notice that the First Law of Thermodynamics is not being broken in any way. It is irrelevant.

The lower metabolism means you feel feel cold, tired and hungry. Worse, the weight eventually plateaus and then as you decide that it’s not worth it, you start to eat more, say 1400 calories thinking that it’s still not as much as you used to eat. Hunger hormones are increased because the body wants to burn 2000 calories and you are only taking in 1200. So weight starts coming back. Sound familiar?

Weight loss by reducing insulin

Well, that was fun. What happens when you use dietary strategies that instead target insulin? Low carb High Fat (LCHF) diets, ketogenic diets, and the ultimate insulin-reducing strategy, fasting all target the reduction of insulin. CICO6What happens?

Since the point of these diets is to lower insulin, stored food energy (fat) can be broken down to power the body. Since the body wants to burn 2000 calories a day, it burns 1000 calories of fat and 1000 calories from food.

What we would predict is that basal metabolic rate remains the same, appetite is decreased and weight is steadily decreasing. Guess what? That’s exactly what is shown in studies. In Dr. David Ludwig’s study and Kevin Halls new study, ketogenic diets do not have this dreaded metabolic slowdown.

Anecdotally, hunger is also decreased with ketogenic diets. The effect is even more striking with fasting. I can only recount my experiences in the Intensive Dietary Management program. We’ve put over 1000 people on fasts of various durations. Many of them drag themselves since they have no energy. After fasting, their energy is massively increased. But despite this, they report that their appetite has shrunk to barely 1/3 of what it was previously. They often tell me they think their stomach has shrunk.

In a sense, it has. But if people are eating less because they are less hungry and then losing weight, that’s GREAT. Because we are now working with the body, instead of fighting it. With caloric reduction diets, people constantly fight their hunger and deny themselves food. Here, people are turning away food of their own volition. Because we lowered insulin.

The first law is right – but this isn’t physics

Notice once again, that the First Law of Thermodynamics is not being broken. There are no calories created out of thin air. It is simply irrelevant to human physiology.

I studied biochemistry in university and took a full year course on thermodynamics. At no point did we ever discuss the human body or weight gain/ loss. Because it has nothing to do with thermodynamics. If anybody mentions the ‘first law of thermodynamics’ regarding weight loss, you, too will know that they are just very smart. Or maybe they just haven’t really thought about what thermodynamics actually is.

Nutritionists on the other hand, especially the calorie counters, can’t seem to say enough about Thermodynamics. They have ‘science’ envy. They desperately want the quantitative and theoretical backing of hard science and therefore pretend that human physiology is like physics, with its hard rules and laws.

News flash, guys. Physiology is physiology and physics is physics. Don’t mess the two up.

FREGLYThe CICO people are Fregley. He is the character in ‘Diary of a Wimpy Kid’ who is the unpopular kid who wants desperately to be liked. CICO people desperately want the approval of hard science that they are willing to pretend that physiology is physics.

Sorry buddy. Just because you have physics envy, doesn’t mean you get to make up stuff. …. (I was going to put in a very crass and crude joke about the Freudian concept of penis envy all for the sake of a few cheap laughs. Against my better judgement, I have removed it.)

You also can’t use the Heisenberg uncertainty principle for weight loss. The Bernouilli Effect doesn’t apply to the urine stream. Physics is physics. Physiology is physiology.

Fasting vs. calorie reduction

Sometimes I’m asked the question about the difference between fasting and calorie reduction. Doesn’t fasting reduce calories? Yes, but that’s not the point. Fasting is about reducing insulin. This allows you to release some of the stored fat energy so that you don’t need to or even want to eat so much.

What drives me crazy is this. The Biggest Loser study proved that cutting calories is a terrible, horrible, no good and very bad strategy, virtually guaranteed to fail. So, in all these articles talking about the Kevin Hall study, what do the ‘experts’ suggest instead? Cutting your calories!!

The only thing worse are those ‘experts’ who claim that that the key is not to define success by weight loss. Win the Diet Wars by not even trying. Buddy! People want to know how to lose weight. Success is defined as weight lost, not loving your body the way it is. As Justin Bieber would say – Go Love Yourself. I wanna know how to lose weight. That’s what The Obesity Code is all about. If you want to know how to lose weight, first understand what causes weight gain.

T2DEpidemic3What happens when you recommend a diet that is guaranteed to fail? Well, you might get a huge worldwide epidemic of type 2 diabetes and obesity.

Unfortunately, all the nutritional authorities all belong to the same CICO cult, and we are all paying the price for their stupidity. You thought Scientology was bad. CICO is even worse.

Let’s consider these simple facts. We’ve recommended cutting calories for weight loss for the last 40 years. During that time, we’ve had a huge obesity epidemic. All the science suggests that caloric reduction as primary is doomed to fail. Senior researchers, academic physicians and virtually all health associations continue to recommend it. They are sheep, constantly bleating. Count your calories! Cut your calories! It all comes down to calories! Anybody who believes otherwise doesn’t believe in the universal laws of nature! I have physics envy!

One article interviewed ‘leading obesity experts’ and came up with these tips. Exercise regularly. Cut calories by avoiding high fat foods. Eat breakfast. Count calories. So, in other words, they would give the exact same advice that we’ve been giving for the last 40 years even as the obesity epidemic overwhelms our health care system. Hey, Julia Belluz, the 1980s called, they want their diet advice back.

O…..M…..F…..G….

The lunatics are running the asylum. In discussing the physiology of obesity, the First Law of Thermodynamics is not wrong – it’s irrelevant.

A better way

How to Lose Weight

Earlier by Dr. Fung

How to Fix Your Broken Metabolism by Doing the Exact Opposite

The Biggest Loser FAIL and That Ketogenic Study Success

Videos

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
The Etiology of Obesity – Dr. Jason Fung

More with Dr. Fung

Dr. Fung has his own blog at intensivedietarymanagement.com. He is also active on Twitter.

His book The Obesity Code is available on Amazon.

The Obesity Code

20 comments

  1. Helen
    Wow, I love the man's passion. I'm so happy & excited that my wonderful dietitian convinced me to finally embrace the wonderful world of LCHF. Thanks for great articles & information.
  2. Mahdi
    Great article, Dr. Fung
  3. Apicius
    I'd like a bone-head dietician convince me that they understand the laws of thermodynamics....while trying to light a wet log on fire in one vessel, while trying to light gasoline in another vessel. If in both cases, the same amount of calories is present in the fuels (wet log versus gasoline), I'd like to hear the brilliant testimony of the bone-head dietician explain to me how the burning action will be the same for both substrates, because of course, the laws of thermodynamics would say they should both burn equally.
  4. Tim
    I'm not sure I buy the alternative hypothesis. It fails to explain how people on Atkins eat 3000 calories and LOSE weight. I think there should be an arrow for "food your body can't use and goes out as waste". Am I wrong? The alternative hypothesis would have these folks bouncing off the walls.
    Reply: #15
  5. KarenNT
    I've been trying to explain this to people in laymens terms for some time now. So nice to hear it explained properly!
  6. David T Darby
    Tim, you obviously missed the point. It's about INSULIN REDUCTION. You eat food which cause insulin to be dumped into the blood system you get fat storage...no insulin input, no fat storage.
  7. Barbara
    Tim, not everyone on an Atkins diet eats 3000 calories either. Someone with 200 lbs to lose might need that much - but it would be high fat, moderate protein and low carbs. Someone with 20 lbs to lose would not need or WANT 3000 calories. What you have stated is one of the myths circulated about Atkins - just not true. The alternative to high carbs is high fat. That gets the body to burn its stored fuel. It DOES make sense whether you buy it or not.
  8. Rick
    I am a research nutritionist, and I agree that insulin is key to losing weight and cutting carbs works. But I see that you say the first law of thermodynamics is irrelevant, then show that decreasing insulin response is an effective way to decrease intake, and ACCORDING TO THE FIRST LAW with decreased intake and maintained metabolism you mobilize more fat and decrease body weight. So you are using the First Law but adding something else too. The First Law just says these things add up, which they do. I don't disagree with your conclusion, but as someone who believes in physics, I think the argument would be stronger not to suggest you are refuting physics.
  9. Thomas
    David, Tim’s point is right (think you misunderstood it?). When on a keto-type diet, you can over-eat quite a bit and still lose fat weight. This isn’t explained by Dr Fung’s theory.

    Look up an experiment by a guy called Sam Feltham, he ate 5.200 kcal per day over 21 days and lowered his fat % by about three units. He tried the same with a normal (UK) diet and gained a bunch too, felt awful apparently. Exactly in the same way we would feel awful on a high carb diet.

  10. Peter
    The first law is neither irrelevant nor is it wrong. The law applies to human beings as much as it applies to everything else. The only thing is that the simplistic view of the human body as used by the calories in/out brigade is too simplistic. Other things are going on that are affecting that energy balance. Factor everything in and I think you will find that not one scrap of energy has been created or destroyed.
  11. Tom Bentley
    Calories apply to the substance not the person.
    Calories are a measurement not a substance. You can’t ‘burn’ calories.
    The calorie was first defined by Nicolas Clément in 1824 as a unit of heat energy.
    He taught a course in industrial chemistry that emphasized the thermodynamics of steam in relation to powering steam engines.

    He developed methods for calculating the maximum amount of energy that could be obtained from a kg of coal. This was to identify what was the best source of fuel for the stationary steam engines of the day.

    The first and second law of thermodynamics refers to a closed or isolated system. The human metabolism, of 55 hormones, Is far from a closed/isolated system.

    Dr Zoe Harcombe has presented on calories a couple of times and explains that counting calories is far from an exact science and can become ridiculous

  12. Peter
    The human body is a closed system. There are a great deal of interactions, chemical processes, energy consuming activities including growth, generating heat, pumping blood around the body etc but it is still a closed system. I am not ignoring the effect of hormones nor am I ignoring the massively complex entity that is the human body but to conclude that the 2nd law is either irrelevant or somehow does not apply is naive.
  13. Loretta
    The laws of thermodynamics apply to the human body just as surely as the laws of gravity do. But neither of them are useful tools for understanding the path to weight loss.
  14. Francisco Navarro
    This is complete bullshit. If you eat at a calorie deficit even if it comes 100% sugar you will lose weight you probably won't be healthy but yoy will lose weight. The truth is that when it comes to weight loss total calorie intake is king. where is the energy going to come from if you dont provide the energy from the food you take? you can lose weight on a twinky diet or even a Mcdonalds diet as long as you track your total calorie intake. these are just extreme examples but I'm simply talking abour weight loss not healthy eating nor general health. Theoretically the low carb diet makes sense but studies that support this claim did not equate for total calorie intake. When you equate total calorie intake both low carb and moderate/high carb diets where found effective in weight loss proving that when it comes to weight loss, total calorie intake is king.
  15. Francisco Navarro
    People that succeed on an atkins diet is because they are eating at a calorie deficit. They would have to drink oil and eat a ton of bacon to be eating that much. those who lose weight is because they eat at a calorie deficit. There are also people who follow the IIFYM (if it fits your macros) aproach and they eat pop tarts and all kinds of junk and they always lose weight as long as they are eating at a calorie deficit. you just have to track your calories and macronutrients with something like my fitness pal or some other app.
  16. David Harralson
    One thing not mentioned is a person's efficiency in converting input calories to calories available to the body, for energy or fat storage. Simplistically, high glycemic foods are usually converted efficiently to available calories and, when in excess, are then stored as excess energy, usually as weight gain. If the body cannot convert the calories presented to it to energy, the body does not store excess calories and thus does not accumulate weight as calorie storage.

    So, if you eat foods that your body can convert to energy efficiently, then you need fewer raw calories to maintain a given weight. Conversely, if your body cannot convert the presented calories efficiently, then the body need more presented calories to obtain a certain amount of utilized calories.

    This is the basic theory in the back of some diet regimens. But, every person's body has differing efficiencies in converting presented calories in different formats. So some diets may produce weight loss in some individuals and produce weight gain in other individuals.

  17. Sambar
    I'm not sure who's right. Everyone has studies to back up what they are saying.

    We need a great debate of some kind.

    Only thing I'm 100% sure of is fasting has kept me warm and slender where as other diets (including keto without fasting) makes me cold and gain weight after a couples of years on it.

    The fasting is increases my metabolism. I'm not sure macros are behind that though.

    Either way I'm grateful to Dr Fung. Without his confidence I would never have fasted and I would still be morbidly obese with a likelihood of T2D.

    I'm not sure if calories are King but I'm sure Dr Fung is.

    Thank you from me and my children. ❤

  18. Teymur
    Brilliant! Just brilliant! So few people actually understand the real reasons behind fat gain (and other health-related problems that come with following conventional "food pyramids" and CICO advice) and yet so many are ready to defend the stupid notion of calorie management - this article is a ray of light in a sea of complete darkness. Thank you!
  19. Moses
    I just find it extremely entertaining that he believes physics has nothing to do with physiology. As an individual who has studied and currently do research in biophysics, all of this is written into computer simulations with variable initial conditions. Also, the crack about the Bernoulli principle is correct; biophysicist do not believes that to be the case. It sounds like you’ve only discussed introductory level topics in physics and have the gall to jab at a field you clearly do not understand, “Dr. Fung.” Mind you, the data found always matches simulations. That’s the point. If you have the physics correct, not the introductory level with idealized systems such as the ones you’ve presented, then all things follow the simulation.
  20. Robin
    The problem with low carb is that it gives me panic attacks. I never get them, otherwise. Other people have complained of this symptom, too.

    It seems to have something to do with serotonin/adrenal problems. What about focusing on cutting fructose (I have fructose malabsorption, anyway.) and a somewhat more moderate complex carb intake? Like enough to avoid panic attacks? I find that about 20 grams of carbohydrate per meal, or the equivalent of a slice of toast, works for me.

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