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

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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)

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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)

In nutrition science, the blind lead the blind

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Obesity is generally caused by eating too much and moving too little

If you want to lose weight, don’t eat. This is not medicine, it’s thermodynamics. If you take in more than you use, you store it.

The law of conservation of energy states that energy can’t disappear. What we eat, has to be transformed in other forms of energy. In simple terms, a person’s energy intake must be transformed into bigger muscles, more fat or will be spent as heat/work.


First mistake

The first mistake some “experts” make is to pretend that the above equation gives an explanation or the keys to understand how a system works. What do I mean? It’s very simple: in the above equation, do the terms on the left side of the equality sign depend on the terms on the right side of the sign? Do muscle development, fat accumulation and dissipated heat determine how much I eat? Mathematically, yes, they do, but this approach is stupid, as is obvious when we think about how every term of the equation behaves in the real world.

If you rearrange the terms of the equation, you will clearly see the origin of the first mistake “experts” make, to think that mathematics tell us what to do to control the accumulation of fat:


Does the equation above say that energy intake, energy expenditure and created muscle determine the amount of fat we store? Even if you think it makes sense, I remind you this is the same interpretation we talked about before, and it made absolutely no sense. From the formula of the conservation of energy it can’t be inferred that energy intake, energy expenditure and created muscle determine the accumulation of body fat. Whether the idea is correct or false, is a question to be answered from our knowledge of the how our body works, never inferred from the laws of thermodynamics.

Second mistake

The second mistake some “experts” make is omitting muscle building.


As I will discuss soon, some “experts” tell us that an excessive intake (“eating too much”) and a reduced energy expenditure (“moving too little”) make us store fat. They say that it follows from the laws of thermodynamics. Ok. In that case, I ask why eating too much and moving too little doesn’t lead us to an increase in our muscle mass, instead of increasing our body fat. What part of the above equation says gluttony and sedentarism lead to obesity but not to muscle building? Why is it that all the positive energy balance goes to one of the terms in the left side of the equality sing and not to the other term?

In order to blame the obese of being gluttonous and sedentary, the “experts” make “muscle building” disappear from the equation:


Third mistake

The third mistake the “experts” make is to ignore reality. The theory they think unquestionable is that energy intake is controllable, because it depends on how much we eat, and that energy expenditure is manageable, because they tell us that it basically depends on how much we move:


And the mistake of this theory is that it ignores all the scientific evidence that what we eat and how much we exercise, both of them influence energy expenditure and fat accumulation. In addition, exercise probably is going to make us hungry, and also losing/gaining weight will modulate our tendency to exercise. The theory “eat less and move more” is not consistent with our knowledge about how our body works:


(I’ve reverted again the order of terms in the equality, in order not to encourage the first mistake I pointed out, i.e. thinking that the terms on the right side of the equality sign determine the terms on the left side)

It is perfectly possible to increase the caloric intake, without more physical activity, and lose weight (see, see, see) or gain fat (see). And decreasing the caloric intake has never worked for losing weight (see) because our body reduces its energy expenditure making impossible to lose weight (see). And we can’t take for granted that after a intense physical activity, our body will spend the same energy as if we hadn’t done that physical activity (see). Neither can we assume that the total energy expenditure is independent of what we eat (see). None of the above are effects that can be ignored. Therefore, the third mistake is essentially assuming as true the following hypothesis:

  • What I eat only affects the caloric intake, and not the fat accumulation nor the total energy expenditure. That goes against the scientific evidence. E.g., if I decrease the intake, energy expenditure will be reduced much more than what the “experts” admit.
  • Energy expenditure is a term that only depends on exercise. That is contrary to the scientific evidence. E.g. our body can compensate in the following few hours the energy expenditure created through the physical activity. Another example is that the the specific content of the diet affects energy expenditure. It is different when the diet is based on carbohydrates and when it is based on fat.

Fourth mistake

The fourth mistake is in part the result of mistakes I exposed before, and it is to close the door to other possible causes of obesity. This one is the refusal to listen to other ideas, and later accept or discard them rationally. A not-too-smart “expert” can make all those three previous mistakes, but to rule out, just because, other points of view, is a new mistake. There are other approaches perfectly “consistent” with the laws of thermodynamics (see,see), but they are discarded arguing that anything apart from “eat less and move more” is stupid. A clear sign that the economic interest for continuing without listening is strong.

“Excessive intake” or “lack of exercise”. Those are the only options considered by some “experts” on the grounds that it they derive from the laws of thermodynamics. But, as we have seen, that way of thinking is the result of several thinking mistakes.

It is ridiculous to observe that when an experiment says “it is not an excessive intake,” then they conclude then “it must be lack of exercise.” And when the evidence says that “it is not a lack of exercise,” then they conclude that “the intake must have been excessive.”


Some “experts” in the nutrition field think a physical principle can be deduced from mathematics:


It is not true. Just as a causality can’t be inferred from a correlation, the above formula doesn’t tell us why we store fat and how to avoid that process. It is only a mathematical equality, something that must be fulfilled, nothing more than that. Change the order of the terms, so nobody would imagine that the accumulation of fat depends on what is on the right side of the equation. Add the term of muscle building. And do not confuse energy expenditure with exercise, and neither ignore that what you eat and your physical activity affect all the terms of the equation. Look at the equation again:


Do you see in that mathematical expression any reason to blame the obese for having earned it all by themselves, because they are lazy and gluttonous? That accusation is not based on the laws of thermodynamics, but rather on the ideology of those “experts”. It’s a sign of arrogance. Since it is an idea that is not derived from the laws of thermodynamics, the question is, what evidence do these “experts” have that gluttony and sloth are the causes of obesity, and not, conversely, a consequence of a diet based on the consumption of grains, flours and sugars? That is, what evidence do they have that proves that those “experts” and their absurd dietary recommendations haven’t caused the obesity epidemic? I don’t think they are in a position to blame others for anything. A diet based on flour (grains), sugars and seed oils, or exposure to certain toxics (see), could change our metabolism, leading it to a fat storage mode. That dietary change would end up making us eat more than we spend. If anyone thinks that this hypothesis is not consistent with thermodynamics’ laws, he/she is committing several thinking errors.

Let’s think about gluttony and sloth. If for every two obese men there are three obese women, are the “experts” saying that women are lazier and more gluttonous than men? Seriously? And poor people are lazier and more gluttonous than wealthier people?

Just one more thing: do you think that children grow up because they ingest more calories than they spend? Do you think they stop growing up when their parents decide that they have grown up enough and stop overfeeding their children? Do you think that that idea derives from the laws of thermodynamics?

Further reading:

What mice tell us

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We hear from the obesity experts that “if we create a caloric deficit, according to the laws of thermodynamics we will lose weight.” Since the laws of thermodynamics always apply, the scientific demonstration that a caloric deficit doesn’t work to lose weight (see), leaves us with no doubts:

The idea that to lose weight you have to eat less and move more is NOT backed up by the laws of thermodynamics

It’s as simple as that: if it derived from such laws, it should always work. But it doesn’t work, therefore it is not a logical consequence of such laws.

The dogma “eat less and move more” is wrong and absurd. And from the moment some people “thought” that this dogma was the direct incarnation of those laws, any alternative proposal is said to be contrary to the laws of thermodynamics, and therefore wrong.

Another way to demonstrate that the theory of energy balance is not a corollary of the laws of thermodynamics is finding other theories, different from the “energy balance” theory, that also satisfy the laws of thermodynamics. A few days ago I published an article (“Thermodynamics for dummies “) exemplifying exactly that: how alternative explanations of how you lose or gain weight are perfectly compatible with the first law of thermodynamics. But please note that the fact that a theory satisfies those laws doesn’t mean it’s right, neither that it is useful. “Eat less and move more” is an example of that: it is compatible with the laws of thermodynamics, but it has been proven false. I think it is also counterproductive for human health (see).

The laws of thermodynamics can’t be used to predict the behavior of a complex living organism, it just tells properties of such behavior. It is the physiology of the living organism what determines its evolution. For example, Gary Taubes in one of his videos shows two photographs of the same child at different ages and with different body weight. The first law of thermodynamics can tell us that if you’ve gained weight, then you ate more than you spent. But it can’t explain why the child grew up. Knowledge of how our body works (e.g. the hormones) can help with that, but thermodynamics’s laws can’t. Thermodynamics only tell us that no matter waht happens, and regardless of why it happens, the behavior will fulfill certain conditions. It can’t predict the outcome, nor show us a way to change the process.

The study

There is a very interesting 2007 study named “A high-fat, ketogenic diet you induce unique metabolic state in mice “. I don’t use to give much importance to animal studies, but in this case there is no reason to ignore them: the laws of thermodynamics are always met, also in animals. If the laws of thermodynamics had something to say in nutrition, they should predict the weight evolution of any animal. At the end of the day what the “experts” tell us is that physiology doesn’t count and that gaining or losing weight is a simple matter of eating more or less. Mouse or person, if you eat more you will gain more weight. Mouse or person, if you eat the same amount of food you will gain the same amount of fat.

Mice are divided in four groups, with four different diets. Three of these diets are shown in the table:

Diet Fat (%) Protein (%) Carbohydrates (%)
(C) chow 16.7 26.8 56.4 (6.5% sucrose);
(HF) High in fat and carbohydrates 45 24 35 (17% sucrose)
(KD) Ketogenic 95 5 0% (0% sucrose)

The fourth diet (CR) is restricted in calories and provides only 66% of the normal caloric intake of those small animals.

Mice are allowed to eat ad libitum (i.e. they eat as much as they want to) for two months (except the CR group, for which the amount is restricted). The 3 ad libitum groups (C, HF and KD) eating more or less the same amount (in calories). Caloric intake of the CR group is shown with white circles:


The “Calories In Calories Out” paradigm tells us that those mice that eat a 66% of the intake of the rest (CR group) must end up with less weight than mice from other groups, while the three other groups (HF, KD and C) must end up roughly equal in weight.

“Those who eat less should end up weighing less …”

The reality is that the “Calories In Calories Out” paradigm is wrong: after two months there was no difference in the weight of the ketogenic group (KD, black triangles in the graph) and the calorie-restricted group (CR, circles and discontinuous line). And remember that the CR group had consumed 66% of the calories consumed by the KD group. Very different caloric intake, the same weight result.


How can that be? Are mice violating the laws of thermodynamics? No, they don’t. As I explained elsewhere, thermodynamics doesn’t say that mice who eat much more must end up weighing more. This erroneous deduction is not derived from the laws of thermodynamics. What thermodynamics say is that if even after eating more you end up with the same weight, that means you expend more energy. And so it was. Analysis of heat from the animals revealed that for the KD group energy expenditure was a 15% greater than for the CR group (and 11% higher than the C group). That is, the mice following the ketogenic diet “generated” more heat: they had a higher metabolism than mice with other diets. For example, the 24h measured heat was clearly greater than in the other groups:

And indeed, there were no differences in body composition (body fat mass, and lean mass) between the CR and KD groups. It is also interesting to know that the KD mice showed much lower levels of postprandial insulin, compared to the other groups of mice. A final curiosity: in one study, female mice of the CR group stopped having the menstrual cycle, something that did not happen in the KD group.

A second experiment, from same study. Now for 84 days all mice get fatter and fatter with the HF diet (high in carbohydrates and fat). At that moment, a part of them is moved to the KD (ketogenic) diet. The output? The KD group’s mice lost weight and ended up with even less body weight than mice in the control group. Those who followed the HF diet never stopped gaining weight.

“To lose weight you have to eat less and move more” …

The “Calories In Calories Out” paradigm tells us that to lose weight you have to eat less and move more. Is that what happened in the experiment? Did mice ate less became of the ketogenic diet? No, they continued eating roughly the same amount than before (after the change of diet a little less, then a little more and once the weight stabilized, the same). So how is it possible? Again, mice from the KD group generated 15% more heat than the HF group, and their oxygen consumption (another indicator of the energy expenditure of the mice) was 34% higher than in the HF group.


A few more results:

  • Mice in KD group ended up with virtually the same amount of body fat than those from the control group. The HF group ended up with more than twice as much fat as both groups. KD mice didn’t lose muscle mass.
  • The KD group passed a glucose test with better results than the HF group.
  • In the HF group “exploratory activity” was reduced, but not in the KD group. It could be said that getting fat made them more sedentary.

Eating the same amount resulted in very differently output in terms of weight (and health). The laws of thermodynamics are always fullfilled, what doesn’t are the “theories of energy balance”, i.e. the “eat less and move more”, counting calories, “eat everything but in moderation” and “you are fat because you’re a sloth and a glutton”.

The authors conclude:

By specific dietary manipulation, weight loss may occur as a result of various metabolic changes without restricting calories.

Losing weight without eating less and without reducing your metabolism … All this reminds me of the Sam Feltham‘s experiment (who, by the way, recently published a book ).