Can overeating be a cause of obesity?

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What is the meaning of “overeating”?

I would say it is not called overeating, unless we think there is a negative consequence. If we say it is “overeating”, we should be able to say it’s “too much” food, “beyond a desirable amount” of food, and you must do it frequently, because otherwise you are not supposed to get the negative output (e.g. getting fatter). There must be a negative consequence and we all could agree that the negative consequence is getting fatter (and maybe sicker). Therefore, as I see it, overeating means eating so much food that something detrimental happens to you.

Note: the term “overeating” assumes that food quantity causes fat accumulation. That is the reason why, IMO, talking about “overeating” is always an error.

Can “overeating” be a cause of obesity?

if we get fatter and heavier, more energy enters our body than leaves it. Overeating means we’re consuming more energy than we’re expending. It’s saying the same thing in a different way”. Gary Taubes

Overeating is the same as getting fatter. It can’t be a cause of getting fatter because they are two ways of saying the same thing. Having problems paying attention and sitting still in a seat doesn’t cause ADHD.

But still, some people think eating “too much” could be a cause of obesity. The question here is “too much, compared with what?“. People use to say “more than our needs”, but the reality is there is no such thing as “our needs”, i.e. a level of caloric intake beyond which we get fat. We only know if we are overeating if we get fat. Even if eating a diet with 2500 kcal/day your weight is stable, you can’t say a 3000 kcal/day diet is going to make you fatter. It could even make you leaner.

Blaming obesity on “eating more than was expended” is  incorrect because whether more was eaten than expended can’t be known unless the patient is already obese. Bill Lagakos

  • Why are you obese?
  • Because I overate
  • How do you know you overate?
  • Because I am obese

Unrealistically extreme situations don’t give answers about normal conditions

If a eat 3000 kcal/day of real food and I don’t get fatter, am I overeating?

If I eat 3000 kcal/day of fast food and I get fatter, am I overeating?

What do you think?

is it impossible to gain weight if you eat let’s say 500 grams of fat a day, on a real food, low-carb, high-fat diet? (see)

That would be 4500 kcal/day only from fat. That would be unusual and probably unnatural: you have to force yourself to eat that much. Therefore we are prone to think it may be harmful and/or fattening, and for that reason we are prone to say that that is “overeating”. Since we perceive that that is a forced situation, we probably could say that in that case overeating is probably causing obesity. But, is that a proof that “overeating” is a cause of obesity in normal people who don’t force themselves to eat for three? No, it isn’t. It just means that an unrealistically extreme amount of food is probably fattening. It doesn’t prove that a positive energy balance is a driver of obesity.

Even if driving you car in the city at 200 mph is a death sentence, that doesn’t prove that driving at a normal speed is dangerous. Talking about an unrealistically extreme case is moving the goalposts.

Whether you get fatter or not with a specific diet depends on the composition of the diet (see,see,see) and also on the physiological response of each person (see,see,see). Even if you are objectively eating “a lot”, it is still about the physiological stimuli you create with that food and about the physiological response of the person eating that food.

For a healthy person, eating a real food diet is probably not going to lead him/her to obesity. That is what we know from what has happened for millions of years to the human species and to other animals. It is eating crap what has made us obese and sick, not “eating too much” because of “food-reward”.

The right question isn’t why we eat so much, it is why are we getting fat. Talking about calories leads us to wrong causes and wrong solutions (see).

Reading further:

On calories, morons and stupidities blessed by the majorities

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This is my favorite post among all that I’ve already posted, and if someone asked me how to start reading this blog, I think I would give him/she a link to this page. Here I write about the nonsense of using the energy balance in nutrition, and I believe I have been able to do that it in a way that makes it possible for anyone to understand that what we have been told is indisputable —the use of calories and energy on nutrition—, is in fact a blatant stupidity. It is very difficult to make other person understand that talking of calories is irrational, because it is an unbalanced fight: what I tell goes against entrenched prejudices (e.g. “people are fat because they eat too much”), huge economic interests and a message that, by dint of repetition, has become conventional wisdom.

It is a rather long post, but I have no doubt the issue is important: talking about calories is the ultimate cause of the obesity epidemic, never its solution. We need a change.

A few days ago an editorial article (see) was published in the Open Heart journal in which the authors claimed that we need to stop counting calories and begin to talk about healthy diets (and they proposed a high fat Mediterranean style diet). The request to stop counting calories was described as “idiotic” by a supporter of the energy balance paradigm (see). In the past they have also used the term “stupids” (see,see) referred to those who believe, like I do, that talking about calories is a mistake that does more harm than good.

I’m too going to talk about stupidity, but this entry is not an angry reaction to people calling me “stupid”. I think that it is ok to use the terms stupidity, idiocy and morons, not used as insults, but describing the apparent lack of intelligence of so many “experts” on nutrition and the nonsense of using the energy balance theory in nutrition. If someone wants to say that an idea is stupid, it is difficult to transmit that message with other words without distorting the essence of the message. I am going to say it, and I will give you my reasons.

Let’s start.

Overweight and obesity happen over time when you take in more calories than you use (see)

The problem of a stupid diagnosis…

Imagine that you are the manager of a restaurant that is going through a bad time, and a business expert gives the following advice to you: “behold, economic problems happen when incomes are consistently lower than costs (see). Therefore, the solution to your problems are measures that a) increase your revenues, as raising the prices, combined with others that b) reduce the costs, like for example cutting down the staff by half or reducing the salaries of your employees“.” You’d certainly think that that person has an incredible intellectual problem, to put it kindly. But it is even more serious than you thought, because when you try to explain to him how stupid his advice is, he says “I can hardly believe you are denying something as basic as that having benefits requires a positive difference between income and cost” .

You summon all your patience, and you tell him that as you see it, the problem with your restaurant comes from the opening of two fast food restaurants in the neighbourhood, and young people, possibly by fad and low prices, are now clients of these places. And you try to explain that, in your opinion, the solution to the problem is finding a way to make those people come back to your restaurant. The business expert has been quietly listening to you, and he says: “ok, what you say may be important, but at the end of the day if your incomes are lower than your costs, your business is not going to survive. You must increase your income and reduce your costs. Any effective solution must comply with something as simple as that“. Now you have no doubts: he has no brain.

The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and calories expended (see)

There we have the stupid diagnosis…

… followed by an even more stupid solution

The ‘economic balance’ equation:

Profits = Incomes – Costs

Do you think that the equation above this line gives you the keys to decide how to fix the problems of your restaurant? If you follow the expert’s advice and cut down your staff, you reduce the costs and therefore, according to the maths, you increase your benefits. And if you double the prices, maths say that the benefits also increase. A combination of all of those measures are all you need to solve the problems of your restaurant, right? It seems to me that maths without thinking are useless to solve the problem of the restaurant.

Only a moron would propose a measure as “cut down your staff by half” without considering first the foreseeable consequences for the business in the short-medium-long term. But the “economic balance” equation can’t tell you nothing about that. It can’t! Because it’s generic and descriptive, not specific and explanatory. It is the same equation for an illegal seller of pirated DVDs, for a Chinese restaurant or for a factory with thousands of employees. The same equation for your restaurant and for my daughters and their weekly pay. That equation has no clue about the particular business we are talking here. That’s really important: this equation doesn’t know the consequences of changing the inputs of the system, like doubling prices, firing half of the staff, or cutting down by half the sallary of your workers. According to maths all that measures increase the benefits, but the knowledge of how a restaurant works tell you that adopting those measures will lead the business to bankruptcy. Taking decisions using just maths is being very very and very moron. I will say it again: very very and very moron. And very moron.

Would you say that looking for ways of recovering the lost clientele implies denying that profits depend on incomes and costs? It doesn’t. But you probably have no doubt that talking about the “economic balance” is a no-brainer that never will give you the keys you need for managing your business. Talking about the “economic balance” is a stupidity that leads to stupid solutions.

In the nutrition field the situation is exactly the same as I have been describing by using analogy of the restaurant. There is no difference. The obesity “experts” propose solutions based on a generic law of physics, which is valid for the human body, for a machine in a factory or for the formation of a star:

Change in accumulated energy = energy IN – energy OUT

And they give us solutions to obesity that are deduced from the equation above this line. Those solutions are stupid, because they ignore the actual behaviour of the system, as was the case with the restaurant’s analogy.

To lose weight, you have to eat less or move more or do both (see)


For the same reasons that firing half of the employees is stupid (because in that you may not be even able to keep the restaurant’s door open), an advice as “eat less” ignores how that action will affect the ‘system’ we are considering, and indeed that reaction will be producing hunger and changing your metabolism with the consequence that your energy expenditure will be decreased and fat accumulation will be favored (see,see). What seems reasonable in the maths domain is actually blatantly stupid, for the simple reason that is doesn’t consider the changes in the behavior of the system, a system that in this case is something as extremely complex as the human body. Increasing your physical activity produces too a compensatory reaction of your body, which tends to reduce your energy expenditure or increase your caloric ingest (see,see,see). In the long run, the most likely output will be bankruptcy in the case of the restaurant, and making even more difficult losing weight in the case of obesity (see). None of that can be deduced from maths: it is the knowledge of how the particular system works what gives us that information and what, sometimes, allows us to predict a result. If the question is “how to lose weight”, thermodynamics will not give us an answer. Because thermodynamics know nothing about the effects of reducing your caloric intake, cutting down sugars and grains on the diet or exercising more. Thermodynamics only allows us to know in advance a feature of the outcome, but doesn’t tell us what is going to happen. What about the energy balance? Is it fulfilled? Yes, it is. No one is denying the laws of physics, just in the same way that nobody denies that profits depend on incomes and costs. In the case of the human body, the system will behave as it has to behave, and at all times the accumulated energy will satisfy the above equation. But the output can’t be deduced from mathematics, only from understanding the behavior of the particular system that we are talking about. And it is not the same talking about the human body, than talking about the body of a mouse or talking of a machine in a factory. Using another analogy, thermodynamics says is that if I want to distribute 10 dollars among my daughters, the sum of the money given to both of them will be 10 dollar. Undeniable. We know that for sure. But thermodynamics don’t impose conditions on how the sharing out will be. Any result is possible as long as it meets the condition that the sum of money is 10 dollars. Knowing that feature of the result doesn’t tell us a thing about how that money will be distributed.

Thermodynamics says that if a fat cell, an adipocyte, fat is accumulating, in that cell enters more energy that it comes out. Thermodynamics can NEVER tell us under what conditions the cell will accumulate or lose fat, because that depends on the physiology. In no case, never, we will find a solution to obesity that is deducted from the laws of thermodynamics. Never talking about calories is going to give us the answer we are looking for: let’s talk about metabolism: the behaviour of the human body.

if you want to prevent obesity, eating less and moving more works every time (see)

There you have the stupid solution (please, don’t believe it works every time: it has never worked) and…

… that they only use for obesity

If I wanted to build my muscles a little, that would increase the accumulated energy in my body. Do you agree with that?

Do I have to become a glutton and a sloth to become a body builder? Doesn’t that ring a bell? How can the experts explain that the advice to build your muscles and the advice to increase your body fat is different, if, according to their theories, in both cases what we need is a positive energy balance? Why don’t they use the energy balance theory to tell us how to build our muscles? I think that question is really important and I believe the answer gives us a big understanding of the problem.

Why is it that nobody says bodybuilders are gluttons and sloths? Have you ever wondered why people increase their energy expenditure in the gym when in accordance with the theories of energy balance what they need to build muscle is a positive balance, not a negative one?

The questions above lead us to an obvious conclusion: the calories are use in obesity because they blame people with weight problems of being responsible for their condition, because the “experts” know that obese people are sloths, lazy, inactive and have no willpower. Without prejudices towards them we wouldn’t talk about calories. Without prejudices towards them, the “experts” would be looking for the real cause of the problem, which, as in the case of the restaurant, it is not an imbalance, neither of power nor of money.

Let’s talk about a new example. If I want my hair (see) to grow, what do the laws of thermodynamics say I have to do? It is clear that I “need” to create a positive energy balance, right? Should I become a sloth and a glutton again? Or, may be, the hair will grow if it has to, and the end result will simply be that part of the energy consumed is stored in those hairs? The laws of thermodynamics are met, no doubt about that, but thermodynamics aren’t going to tell us if the hair is going to grow or not, no matter if I force a certain deficit or surplus of energy. Eating more that you spend won’t make your hair grow, and eating less than you spend won’t make your hair shrink.

From the thermodynamic point of view, obesity is a disease of simple etiology, the consequence of a prolonged positive energy balance. (see)

From the thermodynamic point of view, the hair growth is a process of simple etiology, the consequence of a prolonged positive energy balance.

In the above quote, I’ve replaced the original text, “obesity” by “growth of hair”. In both growths there is a positive energy balance, but only in the case of obesity, the “experts” say that the energy balance is the cause. And anyone who said hair removal could be achieved with a negative caloric balance (see) would be considered a moron.

Why is it that we talk about energy in the case of obesity, but not in the case of hair growth nor in the case of muscle development, nor in any other cases? Because talking of energy is the excuse the “experts” need for telling us what they “know” from the beginning: obese people are gluttons and sloths.

A thermodynamics problem: yesterday your energy intake was 2000 kcal, with an energy expenditure of 1995 kcal and the remaining 5 kcal were stored in the form of hair growth. How many calories do you have to ingest today so that your hair doesn’t grow?

If you haven’t tried to solve the problem above, do so, please.

Summing up…

“Eat less and move more” is a solution deduced from maths, not from the knowledge of the human body works. An its deeply stupid origin is compatible with the fact of that for the majority of us it doesn’t work for long term weight loss .

Compute your costs and adjust your incomes so you have profit. Problem solved

Even the village idiot understands that the economic problem of the restaurant is not caused by having less incomes than costs, or that thinking in those terms can never help solve the problem. If we understand that — and only a moron wouldn’t —, it is easy to see that obesity is not caused by ingesting more energy than is spent, and thinking in those terms can never help solve the problem.

Saying that obesity is caused by an intake too big for your spending is a stupid diagnosis that leads to stupid solutions. To correctly diagnose the problem and find a useful solution, you have to understand the behaviour of the system we are talking about. However complicated the human body may seem, thermodynamics don’t simplify the problem, because they don’t help to diagnose correctly the problems nor to find solutions to obesity. Talking about energy is the cause, not the solution to obesity (see).

The problem is the excessive fat accumulation in adipocytes, right? The questions should be what controls the accumulation of fat in an Adipocyte. An excess of circulating fatty acids? Too high levels of one hormone in regards to another one caused by an excess of fast-absorbed dietary sugars?

There are people that no matter how you explain that talking about calories is stupid, they reply with claims like this one :

FACT: You can gain fat from eating too many calories (Healthy food or junk food)

Do we see the errors in their logic? Although I don’t want to go into detail about this comment now (I leave that to a next blog entry), it should suffice to express that sentence in terms of the analogy of the restaurant to see the absurdity of the comment:

FACT: If your income is lower than your costs, the restaurant won’t have profits, no matter if you regain your old customers or you don’t

Does anyone believe that increasing the incomes and reducing the costs is the law that allows us to save the restaurant? It is not easy to accept that people can be so oblivious.

Everybody can’t be a moron!

It is the fallacy of quantity: all that people can’t be wrong! But no one said everybody is wrong. A lot of people are, too many, if you ask me, but not everybody. Have you noticed how many people out there is “forget the calories, forget processed products, cereals and seed oils”? Not everybody is saying calories should be considered.

The first thing I want to point out, is that we talk here about a herd of buffaloes: if the leading buffalo changes his mind, the rest of the buffalos will follow him to death. They are not a lot of buffaloes that are wrong: the only one that is wrong is the leader, i.e. the U.S. Government. The rest of the world simply don’t have a saying. They follow their leader.

I recognize that this kind of sarcastic comments make me uncomfortable. So you say all the Governments on earth are incompetent in matters of nutrition?The purpose of this strategy is trying to avoid thinking, by trying to finish the conversation by ridiculing the other person calling him/her crazy. This tactics are typical of those who work as preachers of the official truths: they claim to be the safe, sensible options, and anything else are “fad diets” and health risks.

I don’t have an explanation that seems sensible to why so many people are so wrong, when it is assumed that so many people can’t be wrong. And I am sure that looking for explanations to this fact is a trap, because no possible explanation makes favors the one who gives it.

When someone uses this type of fallacious arguments, you have to understand that already have made the decision to not questioning the sayings of the majorities. They won’t have critical thinking, no matter what you answer to the question. They want to follow the leader of the herd without questioning their decisions. No answer, no matter how ingenious and clear it may seem to you, is going to force that person to think for him/herself and question their beliefs.

“No one has said that all of them are morons. There are lot’s of people who understand that talking about the energy balance is nonsense”

“I can’t explain it. May be you can explain to me how is it that we have let the prejudice towards the obese people determine the policies in the fight against obesity”

“Are you you saying that those who think like I do are the morons? Can you give me the reference of just one scientific study where caloric restriction has proved being useful for long term weight loss? You seem to be so sure that it works…”

In general people don’t want to hear you, when what you tell them goes against what is officially established. People link what comes from “official” sources with the sensible, safe option. Moreover, they think their knowledge about nutrition is not enough for questioning the official guidelines. They criticize what they perceive as “alternative”, something very human, but the reality is that those who use these arguments have never questioned their own beliefs or have a formed opinion, they only repeat dogmas.

Although almost all the Governments on earth, and most of the scientists, may recommend “eat less and move more” to prevent/cure obesity, that doesn’t change the actual effectiveness of the method according to the scientific literature, which is none (see, see, see). They are legion and they are the ones who impose the guidelines, but that doesn’t make their message right. The answer is: Yes, they are wrong. And the important question is how you can we escape from the chaos created by the energy balance theory. Looking for an answer to how it is possible that they are so wrong usually leads to nowhere.


Hardly in the history of human errors we will find something as amazing as the energy balance con

Just to end the entry, and increasing the risk of making it even larger, I’ll briefly tell the story of Ignác Fülöp Semmelweis, a Hungarian physician. This doctor, back in 1840, observed that, in his hospital, the mortality rate among mothers when giving birth was different between the two existing delivery rooms. Semmelweis realized that there was a difference between those two rooms: one of them was used by the medical students, while the other one wasn’t. And since medical students helped in childbirth after having forensics lessons in which corpses were manipulated, he postulated the hypothesis that perhaps some kind of matter that those students were carrying in their hands, coming from the corpses, was the cause of the higher mortality rate in that room.

The medical establishment of that time rejected the need to take hygiene measures during childbirth. Semmelweis wanted to force the students to wash their hands before entering the delivery room, and he was fired because of that. His supervisor dismissed Semmelweis’ theory and blamed the high rate of mortality to the incompetence of the students, expelling lots of them.

A couple of months later, Semmelweis returned to the hospital, working this time in the other delivery room, the one not used by the medical students. He did some tests, e.g. he lead the students to his delivery room and checked how that change increased the mortality rate (and he was the good guy!), but according the european leading surgeons and obstetricians ignored or rejected his discovery and they even accused him of using falsified data.

In the words of Professor hebra: “When the history of human errors is written one day, it will be difficult to find such a striking example, and people will be amazed at how such able and specialised persons could be so blind and stupid in their own field of science“.

When you know what is happening in the nutrition field with the energy balance and calories, the history of Semmelweis causes no surprise. What I find striking is the use of the term “able”.

Further reading:

Technically correct

(Versión en español: pinchar aquí)

An explanation can be technically correct, and at the same time idiotic if it is used as the foundation of a solution.


Do you think that the energy balance theory is helping us understand and find a treatment for obesity?

Why hypocaloric diets won’t help you lose weight? (1/2)

(Versión en español: hacer click aquí)

There is no excuse. People who are obese are so because of their inability to follow a diet plan and exercise. If they did that, they would lose their excess weight.

We calculate the energy expenditure of our body, we discount a few hundred calories, we adjust our intake to that number and we increase our physical activity. It can’t fail, right? But it doesn’t work. And the “experts” have no doubts that the problem is that people don’t follow their instructions. If only they had a little willpower! If only they were virtuous, as thin people!

In a time of crisis, you waste less and you get more of what you have

And so does our elephant (see,see,see), whether you aknowledge it or not. If it doesn’t get enough food, it will spend less energy and it’ll be more efficient with its energy expenditure. Our elephant doesn’t want to starve and it defends itself from the perceived situation of lack of food. And you won’t deceive it, because it has food or it hasn’t, no matter the tricks you use to give it less food than it asks or needs. Weight loss is not about appetite control, or deceiving hunger, but about understanding how your elephant behaves.

The challenge with your elephant is one you can’t win

Is that so?

Yes. First of all, because the scientific evidence is overwhelming: eat less and exercise more doesn’t lead to a significant weight loss in the long term (see). And the reason doesn’t seem to be that people give up the diet, because it doesn’t work either when caloric restriction is sustained over time (see). Moreover, you don’t need scientists to know that, because it is what we see with our own eyes: people are unable to lose weight and stay slim just by eating less.

Have a look at the following scientific experiment: two years in duration, in which weight is lost during the first six months.On average participants lost 14% of their weight, about 9 kg. Then the weight is kept stable for eighteen months. The experiment ends at the 24th month. The graphs below show the weight lost by each participant in Kg (graph on top) and  the same data as a percentage of the initial weight (graph on the bottom).


The most interesting result from this study is that after those two years, after one and a half years keeping their weight stable, subjects’ metabolism was still altered. Their body burned virtually only carbohydrates and no fat. The body was in a “fat gain mode”. Six months after completing the experiment (month #30) they had already recovered the lost weight, something you can see on the right side of the previous graph. And their body was still “impaired”: it was still burning less fat than a control person who had not lost weight and gained it back. In the graph below this lines the white box shows the daily amount of burned fat. Data is shown for a week after the end of the experiment (month #24) and six months after the end of the experiment (month #30), compared with a control group:


At the end of the the experiment, month #24, the total energy expenditure of the participants was 1770 kcal, compared with 1950 kcal before starting the experiment. In other words, after one and a half years keeping their weight stable, their metabolism was reduced by almost 200 kcal/day and burning virtually no fat. Six months after the end of the experiment, month #30, the participants’ body mass was 68.5 kg on average, compared to 68.3 Kg in month #0. And their energy expenditure was 1840 kcal/day, still lower than the baseline value of 1950 kcal/day. They had already gained the weight back and their energy expenditure was still reduced.

My conclusions

In short, when forced to suffer a caloric restriction and weight loss, our elephant reduces its energy consumption and gives priority to body fat gain (So cute! it only wants to store fat so it has no energy problems in the future!). These physiological changes remain in the long-term and smash the possibility of keeping the weight loss in the long term.

If we also take into account that hypocaloric diets make you hungry, it is very likely that given the absence of benefit and being that hungry, the person choses to eat a normal amount of food. That will only speed up the inevitable, which is to regain the lost weight. But even if you don’t start eating a normal amount of food, you will not get good results.

Some people say that even if hypocaloric diets don’t work for weight loss, at least for a while (until you return to the baseline weight) your health benefits from a smaller body mass. I don’t think it is clearly so. Losing weight following a low calorie diet is a bad idea that can damage our body in the medium and long term. Dieting may have benefits, but it also has a risk. You can’t advice people to lose weight with caloric restriction without warning them that 1) the method doesn’t work for long term weight loss and 2) they can damage their metabolism. Moreover, scientific evidence (see) suggests that “dieting”, by itself, increases the risk of gaining weight in the future. “Eating less” is not a path without consequences.

Read the second part of this article: 


Why hypocaloric diets won’t help you lose weight? (2/2)

(Versión en español: pinchar aquí)

In a scientific experiment (“Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight“), three types of participants are compared:

  • Those who keep their weight stable
  • Those who have just lost 10% of their body weight
  • Those who lost 10% of their body weight, and have kept that loss for at least one year


Look at the graph above this line. It shows the difference between the actual total energy expenditure (TEE) of the participants and the expected value depending on their age, fat mass and fat-free mass. The black diamonds correspond to the people who didn’t lose weight, and the average value matches the prediction. The open circles belong to the energy expenditure from those participants who had just lost 10% of their body weight: 200 to 650 kcal/day less energy expenditure than expected. And the hollow squares correspond to the energy expenditure of those who lost their weight at least one year ago: between 50 and 800 kcal less than expected. These people have an altered metabolism, despite having kept their weight stable for a year. Their body is reluctant to accept the new body weight. An average reduction in expenditure of 450 kcal/day is striking. And this energy reduction must be added to the expected reduction due to weight loss.

Also shown in the graph are the changes in the resting energy expenditure (REE) and non-resting energy expenditure (NREE) and we can see that just looking at the resting energy expenditure we wouldn’t see the magnitude of the problem. It is the part of non-resting energy expenditure the one that has substantially changed. We can interpret this saying that our body uses the same energy as before to maintain the basic functions, but it has become more efficient at doing any other activity, such as walking. We do the same activity but with less energy than before losing weight.

In another scientific study (“Low-dose leptin reverses skeletal muscle, autonomic, and neuroendocrine adaptations to maintenance of reduced weight“), we get the same result. Participants lose 10% of their body weight with a low calorie diet. The diet is adjusted to maintain the lost weight and their total energy expenditure is compared with the baseline value:


The result of the experiment is that they use far less total energy (TEE) than before, 22% less, as indicated by the gray bars in the graph above this line. And the researchers said that the reduction couldn’t be explained because of the weight reduction. In a 2000 kcal/day diet , a 22% reduction is a reduction in energy expenditure of 440 kcal/day. Therefore, to prevent weight gain they shouldn’t go above 1,600 kal/day. You’d have to eat much less than usual just to keep the weight loss, and that is the number as long as your metabolism is not further reduced because of eating so little.

The above graph confirms the idea that the REE, the resting energy expenditure, may not reflect the change that has occurred in metabolism, since in this case the REE even increased a little, when in fact the TEE has decreased dramatically.

Another interesting contribution of this study is that it measured the plasmatic levels of leptin, a hormone, and they found that after weight loss the leveles were lower than the baseline levels. That means that because of the weight loss a hormonal change had occurred. The researchers injected leptin into the participants to raise their levels to baseline and found that the energy expenditure of the participants increased, returning almost to baseline values ​​(white bars in the chart above). Hormonal changes induced by caloric restriction do matter.

Besides the above, the authors measured the efficiency of the skeletal muscle, and found that it had increased by 23%, approximately. That means that making the same physical effort now needed less energy.

In another study (“Changes in energy expenditure resulting from altered body weight“) participants gained and lost weight (+ 10%, -10%, -20%). Once again, the experiment found that the total energy expenditure was very different from that expected using models that take into account the fat mass and fat-free mass. Energy expenditure was increased 500 kcal/day more than expected when they gained weight, and was about 300 kcal/day less than expected when they lost weight. That is what we can see in the following graph:


This graphs below show the total energy expenditure of the participants. White squares for baseline values:

  • a) in the left panel black squares are used for participants that increased their body weight a 10%
  • b) in the right panel black symbols are used for participants that decreased their body weight by a 10% or 20%.

The straight line is the prediction based on the fat-free mass, and we can see that in the left panel, when they gained weight, the actual expenditure was higher than expected (black symbols are on average above the straight line), while on the right panel, when they lost weight, black symbols are below expected values (on average below the straight line).


But there is more: the data above was obtained once the weight was lost and it was stable. But while they were losing weight energy expenditure was even lower (10-15% less), and while they were gainning weight energy expenditure was higher (12% more) than the values shown on the graphs above. Our body resists the weight change and also to keep the new weight.

I know this article is already quite long, but I find it very interesting. Just a couple of studies and it is over.

In the first one (“Effects of experimental weight perturbation on skeletal muscle work efficiency, fuel utilization, and biochemistry in human subjects“), participants lost or gained a 10% of their baseline weight. From an energy expenditure of 2750 kcal/day they should have gone down to 2650 kcal/day because of the weight loss. But it fell to 2175 kcal/day. There was an unexpected reduction of 475 kcal/day. Their body spent a total of 575 kcal/day less than at the baseline. Is this the way of losing weight?

The decrease of the total energy expenditure was a 20%.

They also measured the efficiency of the skeletal muscle, and found that an increased efficiency could explain the 35% decrease of the total energy expenditure. For example, for a 10W workout the expenditure was 1.17 kcal/min in the group that lost a 10% of their body weight, compared with 1.50 kcal/min at baseline. That means, if you lose weight, the physical exercise you do burns fewer calories than those the same physical exercise would burn before losing weight. You deprive your elephant and it gets more out of each available calorie.

Finally, in another scientific study (“Greater than predicted decrease in energy expenditure during exercise after body weight loss in obese men“) energy expenditure is measured in participants while they exercise, before and after losing a 10% of the initial body weight. The graph below this lines shows how after losing that amount of weight, a specific physical effort needs 3.71 kcal/min instead of the expected 4.14 kcal/min. Again, the results show that after losing weight the elephant becomes more efficient, and resists both losing weight and keeping it off.


Weight loss makes our body more efficient and saver. It spends less, and gets more from what it uses.

These results may explain why “eat less and move more” doesn’t work for weight loss. The question now is how much is our body altered in the process of losing weight and gaining it back.

(Click here to access the first part of this article)