The short-term effect of a diet may have nothing to do with its long-term effect (2 of 2)

(Versión en español: pinchar aquí)

In the first part of this article we have seen an experiment that clearly shows that the CICO theory is wrong.

Let us assume that the following premises are true for a normal diet, not one that absurdly forces an excess of food:

  • In the short term, during the first week or the first two weeks after a dietary change, a low fat diet makes you lose more weight than a high-fat diet.
  • As time goes by, a physiologic adaptation happens and the roles of the diets are exchanged, being on average the low-carbohydrate diet better for body fat loss.

I am not saying that the premises are true, I only ask that we assume for now that they are true.

In this situation a person who I will call John decides to do a meta-analysis of weight loss studies and puts together in the same meta-analysis a) a dozen studies with a duration no longer than a week that mostly show a favorable effect for low-fat diets, and b) a few studies that are a little bit longer, a couple of months at most, which show a favorable effect for low-carbohydrate diets.

John mixes all the studies in the same meta-analysis and concludes that since no diet is clearly the best one, the composition of the diet is not that relevant and that what really matters are the calories! a conclusion that is actually in contradiction with each and every one of the individual studies. How do you feel? In this hypothetical situation that I am proposing, the composition of the diet would be key in the long term and the meta-analysis would have reached just the opposite conclusion, generating noise. A person who wanted or needed to lose weight and keep the reduced weight in the long-term would have to choose the right composition of the diet to achieve that goal.

Does anyone believe that the long-term effects of a diet can be inferred from experiments that are shorter than a week? Does anyone believe that the behavior of our body after months of losing weight has anything to do, anything at all, with what happens in the first three days of following that same diet? (see)

Obesity Energetics: Body Weight Regulation and the Effects of Diet Composition

I this article from 2017 its authors present a compilation of around twenty dietary studies. Table 2B shows us data on changes in body fat for these studies and concludes that, on average, low-fat diets help people to lose more body fat than low-carb diets do:

What are not shown in the previous graph are the durations of those studies. I copied the data from the ES column of the graph above (just as shown in that table, without checking the original articles) and I represented those values as a function of the amount of days the participants followed the diet. As we can see in the graph below, in half of the studies the diet was followed for one week or less. The duration of the study in days is represented on the horizontal axis.

Moreover, those studies with a longer duration, those where the diets are followed at least for a month, are favorable to low-carb diets (the one with the longest duration in the compilation did not use a low-carb diet, as I comment below, but two diets very high in carbohydrates):

The conclusions from the authors are amazing:

In other words, for all practical purposes “a calorie is a calorie” when it comes to body fat and energy expenditure differences between controlled isocaloric diets varying in the ratio of carbohydrate to fat.

Can you really deduce that from very short-term diet studies? It is enough for the believers in the energy balance pseudo-science, who, undoubtedly, use this type of articles to prop up their ideology, but for rest of us it is impossible to draw relevant, general or useful conclusions from this collection of experiments.

First, because of their duration: what is relevant is whether there are differences between diets in the long term, and in this compilation of studies no diet has been followed for more than two months. As a matter of fact, half of the experiments are no longer than a week. Do we want to know which diet is more effective in the long term? Let’s do the experiment, instead of making up a result from short-term data.

Secondly, the fact that some studies favor low-carbohydrate diets and some favor low-fat diets does not mean there are no differences between diets. At the beginning of this text I explained that if the differences were due to the duration of the experiment, by combining experiments of different durations in the same data pool the actual effect of the composition of the diet would be obscured in the average, when the reality would be that the composition of the diet would be key in the long-term effect of the diet. As I have said before in this blog, meta-analysis are another way of lying (see,see,see).

Thirdly, because all kinds of diets are being mixed in the comparison, from ketogenic diets maintained for a few days to diets that are simultaneously high in fat and carbohydrates that have absolutely nothing to do with healthy low-carbohydrate diets. For example, in the experiment from Rumpler et al. de 1991, the longest of all those considered in the compilation (see the last graph above), the high-fat diet was also very high in carbohydrates: 46% carbohydrates and 40% fat.

Can we infer from that result anything about a low-carbohydrate diet? Would the result have been the same if the diet had been ketogenic? The authors of the meta-analysis want us to believe that it would, but by including experiments like the one I am commenting in a meta-analysis, all they do is create misinformation.

Fourth, based on short-term studies, the authors of the meta-analysis reach conclusions that contradict the results of studies with longer durations (see). Are most of the long-term studies poorly done and their data is not reliable? Can we deduce that from 4-day long studies that have nothing to do with the long-term effects of the diets? Shall we ignore all the scientific evidence and replace it with the imagination/ideology of the authors of this meta-analysis?

Note, on the other hand, that not even the authors of the meta-analysis believe what they are doing. They downplay their own result by saying that a difference in fat accumulation of 16 g/d is “physiologically meaningless”.

Figure 2B shows differences in the rate of body fat change between diets with the pooled weighted mean difference of 16 g/d (P < .0001) greater body fat loss in favor of the lower fat diets (P < .0001). These results are in the opposite direction
to the predictions of the carbohydrate-insulin model, but the effect sizes are so small as to be physiologically meaningless.

But an energy imbalance equivalent to only 1 g d of dietary fat could explain the current obesity epidemic.

A small persistent average daily energy imbalance gap between intake and expenditure of about 30 kJ per day underlies the observed average weight gain (source)

Yes, this last statement comes too from one of the authors of the meta-analysis, Kevin Hall. He should explain why 16 g/d of difference between diets is “physiologically irrelevant”, as he says, but an imbalance of 1 g/d could explain the obesity epidemic, as he also says. They simply downplay their own result because it is so unbelievable, in the bad sense of the term, so erroneous, that it gives away that something is not right in its origin. Extrapolating this result to the long term makes it obvious that it is wrong. But, if it is not extrapolated to the long term, the authors of the article cannot conclude that “a calorie is a calorie”.

It is not the first time that Kevin Hall interprets very short-term results as a demonstration of long-term behavior (see).

What are the postulates of the energy balance pseudo-science?

We should notice that the energy balance pseudo-science is never explicitly and rigorously formulated in a way that its postulates could be falsified. Other theories are criticized and the followers of this pseudo-science argue that, as the other theories do not seem correct, “then a calorie is a calorie” (see). This is exactly what the authors of this meta-analysis do. It is typical of pseudo-sciences to avoid formulating their postulates so that they can be subjected to falsification. With the energy balance theory the absence of well-defined dogmas allows the coexistence within this pseudo-science of factions that defend postulates that are incoherent among them (see).

The consequences of all this charlatanism are very serious: public-health dietary recommendations are still based on the stupid energy balance pseudo-science, weight loss methods that have never been proved to work are still the official treatment for obesity and we continue to blame the victims for their failure to lose weight, arguing that they are not lean because they do not show enough adherence to the diet (see,see).

As a final note, the fact that something could only be accurately measured in specific conditions, does not mean that what we measure in those conditions is useful. Maybe only weight loss studies that last three days are really reliable, because you have the participants locked in a facility and you have absolute control about what they eat and what they do. You measure everything very well and you control everything very well, but the data that you measure is rubbish because the failure of the diets is a problem that happens after following the diet for several months (see).

Further reading:

The Minnesota Starvation Study

I’m going over some aspects of The Minnesota Starvation Study, an experiment that has been commented previously in this blog (see,see,see).

“The Minnesota Starvation Study”

The objective of the experiment was to study the recovery phase from a malnutrition condition. In order to do so, first weight loss was induced by caloric restriction and physical exercise. The duration of this first phase was 6 months. After those 6 months, the researchers tested different options in the weight recovery phase.

According to the researchers, the rate of weight loss in the first phase approached zero after 24 weeks (see):

The “ideal” relation between body weight and the course of semi-starvation was believed to be that in which the rate of weight loss would change at constant rate to reach zero change at the end of 24 weeks

Mathematically, the general curve required for weight versus time is represented by a parabola with vertical axis and zero slope at 24 weeks.

Note that the researchers tell us that the body weight evolved in such a way that at week #24 there was no weight loss: “zero change”, “zero slope”.

In the picture below we can see the evolution of the body weight of the participants (white dots) and the energy intake during that period (black dots):


The important fact here is the participants always followed a hypocaloric diet and they stopped losing weight. They went from consuming 3150 kcal/day at the baseline to consuming about 1750 kcal/day. Taking into account only the energy intake, they applied a caloric restriction of around 1400 kcal/day:

It must be noted that the present subjects changed from a control average of 3150 Cal. to a semi-starvation average of 1755 Cal.; this represents a potential deficit of 1395 Cal. per day.

After allowing for all individual adjustments in the diet, the average individual daily intakes averaged, for successive months, 1) 1834, 2) 1833, 3) 1766, 4) 1661, 5) 1694, 6) 1764 Calories.

In short, they are living in a facility, their intake is absolutely controlled, they are eating much fewer calories than they used to, and they are also doing physical exercise (therefore, their enegy expenditure is supposed to be high) (see),

The participants were expected to walk 22 mi (35.4 km)/wk and expend 3009 kcal (12552 kJ)/d.

But after 6 months of caloric restriction, although they still have body fat they could lose, they are not losing any more weight. I want to insist on this: they are “eating a lot less” and they are not losing weight.

As I said above, the official goal of the experiment was to analyse the best way to recover from a malnutrition condition. From 6 months (time point S24 in the graph below) onwards, the energy intake was gradually increased. At time point R12, although the participants always had consumed less calories than they used to (red lines in the picture remained always below 100%), they had already recovered almost all the body fat (point marked with arrows on the solid curve) that they had previously lost.


In this study:

  • weight loss reaches a plateau, although the caloric restriction is maintained and there is still body fat that can be lost
  • under caloric restriction conditions, body fat accumulation has been promoted and although the participants never stopped following the calorie-restricted diet, they gradually increased their body fat


When you are “eating less and moving more”, but you reach a plateau, your options are: keep on following the diet and slowly regain the previously lost weight, or you can start consuming a normal amount of food and you will regain the lost weight faster.

We can’t identify the causes of weight regain, but we know the problem is that you lack the willingness to change

A review study has been published recently: “The Long-Term Effect of Energy Restricted Diets for Treating Obesity“.

A few quotes from the study:

Energy restricted diets resulted in an average 2.9% […] greater weight loss compared to untreated control groups.

Weight regain was observed in the majority of individuals in all studies.

Since so many individuals are initially successful in losing weight through an energy intake reducing diet, future research should aim to identify ways to prevent weight regain

When prescribing a diet for the treatment of obesity, health practitioners should discuss with their patients that this intervention is only useful if permanent dietary changes are made. The high chance of weight regain and the mechanisms behind the phenomenon should be explained and a plan should be made to prevent weight regain as much as possible. This plan should include a feasible weight maintenance diet, emphasizing that energy intake will have to be permanently lower compared to the situation prior to weight loss.

Disapproval of those who do not succeed to lose weight, or regain weight, is inappropriate. If weight loss is not achieved, the advice to go on a diet should not be repeated automatically, unless a renewed willingness to change is noted.

A 100 Kg person can expect to lose 3Kg as a result of 3-4 years of dieting. That is just amazing…

The authors, instead of saying “energy restriction is BS, let’s forget it once and for all“, they talk about “permanent dietary changes” and “willingness to change“. They admit they have no clue why weight regain happens, but they ask health practitioners to inform their patients about the causes of weight regain and give them a “feasible weight maintenance diet“. What kind of diet would that be, if they don’t know why weight regain happens? But it must be “feasible“, because, you know, we have a problem of willpower here…

Is this what they are saying?

Dear patient,

energy restricted diets fail for the majority of individuals in all studies, therefore we conclude that a) caloric restriction works for weight loss and b) you, the obese people, lack willpower to stick to the diet, are too stupid to understand caloric restriction or are willingly sabotaging the energy balance theories. 

Future research should aim to identify ways to prevent weight regain, but nevertheless we encourage health practitioners to tell you why weight regain happens and give you a plan to follow in order to avoid weight regain. We know the plan is only useful if permanent changes are made, although we have no idea what those changes are. That’s because no intervention has ever proved to work. But permanent changes are needed and the diet must be feasible, we know that for sure, because we know the problem is that you, the obese people, lack the willpower needed to stick to the diet. And please, stop eating so much.

We will not blame you if you fail. Weight loss needs a strong willingness to change, but we all know that you, the obese people, are weak, lazy and have no willpower. If we advised you to diet again without noting first a desire to change, it would be our fault, not yours.

A desire to change is the key, although we don’t know what kind of change is needed.


  1. Caloric restriction is a weight loss method based on several thinking errors. It’s not derived from physics’ laws, it derives from human stupidity (see,see). There is no good reason for it to work, and as a matter of fact it doesn’t.
  2. Caloric restriction has been tested in hundreds of scientific experiments and it always fails. The method doesn’t work. That is an indisputable fact.
  3. The more likely explanation for caloric restriction’s lack of results is the physiological reaction of our body to caloric restriction. That explanation is based on sound science, from human and animal studies. The idiotic “lack of willpower” hypothesis has no scientific backup.
  4. Caloric restriction has been shown to fail also when there is proof of adherence to the diet.
  5. When a diet based on sugar, grains, seed oils and processed food is adopted, obesity develops. When people go back to a diet based on real food, they lose weight and their health improves.
  6. If obesity were caused by laziness and gluttony, that would mean the world population has suddenly become lazy and gluttonous. The idea that this has suddenly, with no clear cause, happened to all kinds of people in all kinds of countries is blatantly stupid and blames the victim for its condition.


Was there intention to deceive in the Hall et al. study?

(Versión en español: pinchar aquí)

This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity.

It sounds like a relevant study, right? Apparently they show that obese people that restrict dietary fat lose more body fat than those that restrict the same calories from carbohydrates.

Is that so? Have they demonstrated what they say they have?

The study is ” Calorie for Calorie, Fat Dietary Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity “.

Let’s have a look at the data they give us. In the figure below this line they show the change in body fat measured by DXA (dual-energy X-ray Absorptiometry) for the two diets:


Do you see the markers on the right side of the graph, the orange and blue ones, one overlapping the other? These are the fat mass loss they measured in the study: there was no difference between both diets. You should ignore the straight lines because they are just predictions made using mathematical models (and those models are obviously not that good).

Does that mean that there was no difference between diets? No. It means that that difference was not measured. May be if the study had lasted longer, the ultra-low-fat diet could have produced a greater loss of body fat than the other diet. I can’t think of a reason for that to be impossible. But that is not what they measured.

One small comment. The authors tell us that One female subject had fat mass changes measured via DXA that were not physiological and were clear outliers. These data were excluded from the analyses “. What? The only direct method they used for measuring body fat was so “reliable” that they removed the data from one participant because it was not possible? And I have another question: why didn’t they repeat the measure rather than discarding the data from the participant? I don’t understand that they don’t give an explanation about what happened here.

Let’s read again the conclusions of the study: “This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity.”

But we see that the body fat loss was not different between diets. How can they tell us the opposite? The reason is that as they didn’t get the difference they were looking for, they started computing fat loss indirectly, using equations: they knew the fat intake, approximately, they measured the respiratory quotient and from this ratio and using equations they computed the rate of fat oxidation, approximately. Then they assumed that all the ingested fat that wasn’t oxidized was stored as fat. They assumed that no fat could be lost with the feces or could have been used for other functions in the body. The assumption of the authors is that all that unaccounted fat was stored as body fat. To me, as long as the DXA measurement of body fat gave a result that contradicts this indirect computation, this is not enough for the grandiloquent use of the word “demonstrated”.

Let’s read again the conclusions from the study: “This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity.”

The authors speak of “body fat loss”, “restriction of dietary fat” and “restriction of dietary carbohydrate”. Were those the elements analyzed in their study?

Not quite.

“Body fat loss”

We are talking about an experiment in which diets were followed for just 6 days (please check the horizontal axis of the chart above) and the weight loss achieved in 6 days is completely irrelevant. Any diet, even starvation, can make you lose body fat and body weight in the short term. But that result can’t be used when talking about significant weight loss, i.e. to lose a significant amount of body weight in the long term. The interesting data comes from years, not from less than a week.

They should at least have talked about “body fat loss in the extremely short term”, to avoid being misleading.

“Restriction of dietary fat”

They talk about dietary fat restriction, but in this study they only used one amount of dietary fat, 17 g per day. That is extreme and unsustainable in the long-term as it poses a risk of not getting essential nutrients  (see). Our bodies need fat, not only as energy, but because of fat itself and those vitamins found in fats or whose absorption is facilitated by fat intake. The result of this study in no case can be extrapolated to arbitrary dietary fat reductions in a healthy diet.

They shouldn’t talk about “fat restriction”, because they didn’t put to test several levels of fat restriction: they used only a dangerously low amount of fat in the diet.

“Restriction of dietary carbohydrates”

The lower carb diet had 140g carbs/day. That amount is much higher than the recommended values for weight loss with a low-carb diet. In fact we are talking about an amount large even for weight maintenance (see), although not everyone agrees on this point. Designing a diet with a high amount of carbohydrates suggests bad faith when designing the study: it is a straw man. If they really wanted to compare their unreal ultra-low-fat diet with a low-carb diet they should have used a well designed low-carb diet.

They shouldn’t talk about “restricting carbohydrates” instead of saying the specific amount they used: 140g. Their findings may not apply to diets with other levels of restriction and therefore the authors’ conclusions are misleading.

But there is an infinitely more important detail: if we talk about “diets”, we can’t take into account an experiment with a duration of six days. First, because the transition to a low-carbohydrate diet has a transient period, that could take even weeks (see). If they measure parameters during those transition days what we will see is not the effect of the diet, but from the transition between diets. Any researcher in nutrition for sure knows that, so, again, questions about the authors’ good faith arise.

Let’s add more data, One male subject erroneously received the RF diet on the first day of the RC study period and one female subject erroneously received the RF diet on the final day of the RC study period“. What is the effect of mixing the participant’s diets in the results of the study? The results of these two participants were added to the pool of data.

And although the text of the article tells us that “. Subjects received both isocaloric diets in random order”, the truth is that it wasn’t so. Two of the participants received only one of the diets, the RC diet, and their data were not eliminated from the study, as can be seen in Table 3. In the text there is no explanation on why their data wasn’t removed.

Before going on, let’s read again what the authors wrote:

“This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity.”

Body fat loss didn’t differ between diets, fat restriction reached values dangerous for participant’s health, carbohydrate restriction was outside that recommended for weight loss and at least four of the participants’ data are suspicious. Without loss of accuracy the authors could have written the following:

This study, with a ridiculously short duration that gives irrelevant results for weight loss in the long term, calorie for calorie, an unsustainable and dangerously low in fat diet did not produce greater fat loss than a low-carb designed not to work too well“. It seems to me this is a more appropriate way of summarizing their findings.

I was talking about the relevancy of the long-term effects of the diets. And I add to my reflections the importance of appetite reduction. My hypothesis is that low carbohydrate diets may be useful for weight loss for the following reason: carbohydrate restriction allows the burning of body fat, so that, for example, a body that normally needs 2000 kcal, can get 200 kcal of them from body fat, thus requiring only to ingest 1800 kcal per day. That person eats less as a result of losing body fat. And not the other way around.

Why calorie restriction doesn’t work for weight loss? Because if that same person that needs 2000 kcal /day eats just 1800 kcal of a diet high in carbohydrates, that person is starving. And his/her body, his/her metabolism, will react trying to stop the weight loss (see). The rebound effect makes weight loss stall around month 6 after starting the diet (see).

That’s my hypothesis about why some diets may work where others don’t. Can we see that in a study in which diets are followed for less than a week?

Some people argue that this study is irrelevant, since the advantage of the low-carbohydrate diet comes from the loss of appetite, and therefore forcing diets to be isocaloric worsens the result of the low-carb diet. I agree that the advantage has to do with the loss of appetite, but not because of the resulting reduction in the caloric intake (see). In my opinion, the correct comparison is an ad libitum low-carb diet (something that was not done in this study and therefore it is another thing not to like about this study), where the low-carb diet is really low-carb (something also not done in this study) versus a low-fat diet that adjusts its calories to those consumed in the low-carb group: two isocaloric diets in which some participants are starving while others don’t. And then we wait to see what happens in the long term. May be ultra-low-fat diet don’t make you hungry and allow long-term weight loss, but that is something we can’t conclude from this study.

In conclusion, I don’t doubt that an ultra-low-fat diet could, hypothetically, be more effective for weight loss than a low-carb diet. But first they must clarify how they will tune the diet so that it is not a health hazard. If they succeeded with that, I wouldn’t argue against promoting this diet: it may be an option for weight loss. But today the questions are, for how long can you follow their ultra-low-fat diet in this study? What is the risk of not eating enough essential fatty acids or vitamins? What real foods can people eat to get those essential nutrients without, at the same, exceed the limits imposed on total fat intake? In any case, what we need to make clear is that in this study they speak of “dietary fat restriction” but they virtually remove dietary fat from the diet. Their findings can never be extrapolated to other conditions. Don’t let them fool you: this study was not a comparison of “fat restriction” versus “carbohydrate restriction” for weight loss.

This study has been proposed (see) as proof that insulin can’t explain why low-carb diets produce greater weight loss than other diets with the same calories (see) . Falacious and opportunistic argument. Firstly because we can not talk about “diet” when the participants didn’t even follow this way of eating for a whole week. And the same food has different effects within our body depending on the diet we followed in the previous days. The adaptation period should have been respected. And secondly because what has been seen in this experiment is that if fat intake is practically zero (ultra-low fat diet), at least in the very short term the rate of fat oxidation is maintained high and therefore our body burns more fat than the amount ingested. And consequently you lose body fat. That is, if we have alcohol and one match, in this experiment alcohol has been removed and it has been found that under these conditions there is no fire when you light the match. Does that mean that the match has nothing to do with the fire when there is plenty of alcohol? That is, have they demonstrated with this study that with a healthy fat intake keeping blood insulin levels low doesn’t play a role in the accumulation of body fat? Obviously not, they haven’t demonstrated that. Moreover, the hypothesis of insulin would be the opposite of what they tried to prove. In the analogy the insulin hypothesis would be that if there is no match, alcohol is not going to burn. Both “extreme situations” are possible and confirming one of them doesn’t mean the other one is false.

With that said, I don’t believe the insulin hypothesis is an absolute truth (see , see). It is a simple way to explain  why counting calories is nonsense (see) and it is a simple way to explain why reducing carbs is healthier than other dietary approaches. I do believe talking about of insulin is better than talking about calories to make people understand how to eat healthy.

I have four questions.

The first one: is it reasonable to think that this study was designed, and its conclusions have been written, to fool people by saying that restricting fat is better than restricting carbohydrates for weight loss in people with weight problems? I copy again what the authors say: “This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity.”

The second one: if these authors have demonstrated what they say they have demonstrated, how do they explain all those scientific studies that reach the opposite conclusions, such as this one? Do people systematically in all studies make mistakes that favor low-carb diets? Because if they really have demonstrated that restricting dietary fat produces more body fat loss than restricting carbohydrates, all those other studies (see,see) must have been poorly made. If they have demonstrated that…

The third one: how does the energy balance theory fit in the idea that a low-fat diet produces more weight loss than a low-carb diet, having both diets the same calories? It is interesting how some people have sacrificed, without hesitation, their energy balance ideas when they believed that the low-fat diet was winning.

The fourth and last one: the ultra-low-fat diet in this study is ultra restrictive in fat intake. Are now restrictive diets acceptable, as long as it is fat what is restricted? What about all those falacies about the long term unsustainability of a restrictive diet? Is there no longer a need to eat everything so that the diet is “sustainable” in the long term?

Finally, this is the summary that Ivor Cummins wrote about the article we are talking about:

A little knowledge is a dangerous thing – so much is artfully wrong with this study…’s unlikely to have happened by chance stupidity. This methodology is becoming common – comparing a ridiculously short-term isocalorific pseudo-low-carb (29%), to an ultra impossible low-fat (8%). It is becoming known that short-term ultra-low-fat (whilst ridiculous in real life), can generate the apparent effects that the experimenters are specifically mining for. Keeping the ‘low-carb’ not really low carb at all, enhances the errors, and tuning the timebase to be very short ensures no metabolic adjustment to allow benefit to accrue. The whole deceitful mess is massively magnified by eliminating the crucial hunger-driving factor from the equation. Yes, I suspect these guys know exactly what they are doing here; while it may not be direct remuneration into their personal bank accounts, the question of their funding is still pertinent. What is driving their deceit?

Read more:

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)