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Basic theory of gaining weight


The Overfeeding Experiment Suggests That "Overeating" Is Not the Cause of Obesity


  1. Can overfeeding experiments make people obese? 
  2. Subsequent Overfeeding Experiments
  3. Can metabolism explain this weight regain? 
  4. Difference Between Obesity and Overfeeding Experiments: My Thoughts

1. Can overfeeding experiments make people obese? 

According to George A. Bray (as of 2020, an emeritus professor at Pennington Biomedical Research Center), until the 1960’s, obesity was viewed as a "lack of will power," and many people thought, and some said "if only these patients would push themselves away from the table, they would not have this problem." 

With this view of obesity, he reflects that the turning point for obesity being accepted as a bona fide area of academic interest were the studies on overfeeding. Overfeeding studies began to provide valuable insights into the biology of obesity. For Doctor Bray, who was a postdoctoral fellow at the New England Medical Center Hospital in Boston at the time, the excitement that was generated when the Vermont overfeeding studies were first presented in 1968 was unforgettable[1].

This was the case with the overfeeding experiments conducted by Doctor Ethan Sims in the late 1960’s. Until then, it was commonly believed that, "overeating obviously leads to obesity," so few such experiments had been conducted.

According to Dr. Jason Fung, the author of “The Obesity Code,” Dr. Sims recruited lean students at the nearby University of Vermont and encouraged them to eat a lot to gain weight. However, despite what both he and the students had expected, the students did not become obese. 

Suspecting that the students might have been increasing their exercise, Dr. Sims changed course. He then recruited convicts at the Vermont State Prison as subjects. Physical activity was strictly controlled, and attendants were present at every meal to ensure the calories-4000 per day-were eaten. 

Although the prisoners’ weight initially rose, it then stabilized. While some prisoners gained more than twenty percent of their original body weight, the extent of weight gain varied significantly among them[2] .

Meals in prison

Over two hundred days on this overfeeding regimen, twenty inmates gained an average of twenty to twenty-five pounds. (About 10 kg.) However, once the experiment ended and their caloric intake returned to normal, the men had difficulty maintaining the weight gain, and most shed all the weight they had gained relatively easily. The exceptions were two inmates who struggled to lose that weight[3].


At the time, Dr. Bray was allowed to participate as a co-researcher in Dr. Sims' experiment to examine the metabolic changes occurring in adipose tissue during the weight gain that followed overfeeding. 

Later, in 1972, he conducted his own overeating experiment, using himself as a guinea pig. Initially, he tried to double what he usually ate at each meal, but he couldn't finish, so he switched to energy-dense foods, such as ice cream.

Over the next ten weeks, he gradually gained ten kilograms, and repeated his tests such as measuring the thermic effect of foods.

But once he stopped stuffing himself, his weight rapidly decreased, returning to his original seventy-five kilograms six weeks later, and he has maintained this weight with no trouble ever since.

Following his self-experiment, the other four volunteers in this study began overeating in the summer of 1972. When the experiment ended, all the volunteers returned to their baseline weight. 

overfeeding experiment

Dr.Bray states that this rapid return to normal weight contrasts with the difficulties people with spontaneous obesity have in losing weight, and the even more difficult task of a maintaining a lower weight. Many who develop obesity over years suffer from a different kind of pain than those of us who acutely gain weight by overfeeding. For them, the obesity “slips up” on them and once present, is difficult to reverse.

The history of overfeeding and underfeeding trials and other lines of evidence clearly show that obesity prevention and treatment cannot simply rely on the advice to "eat less and exercise more." [1]

2. Subsequent Overfeeding Experiments

Alex Leaf (Western States University) and Jose Antonio (Nova Southeastern University) reviewed overfeeding studies conducted up to 2017 that evaluated various combinations of macronutrient overfeeding and its effects on body composition. 

They found twenty-five overfeeding studies that reported changes in fat mass (FM) and fat-free mass (FFM), in addition to changes in body weight. The study durations ranged from nine to one hundred days, and all but four were conducted in sedentary populations[4]. Notably, the objectives of each study varied, and not all mentioned weight loss following the end of the experiments.

To give a few examples, a study on identical twins was published in 1990.

■Bouchard (Laval University, Canada) et. al. recruited twelve pairs of young adult male identical twins (twenty-four individuals) with no exercise habits. Each participant's energy requirements were measured during a two-week base-line period, and after that, they were overfed by 1000 kcal per day (comprising 15% protein, 35% fat, and 50% carbohydrates), six days per week, for a total of eighty-four days during a one hundred-day period. The men were housed in a closed section of a university dormitory, and were under supervision by staff all day. 

identical twins

The mean weight gain was 8.1 kg, of which 67% was fat mass (FM). However, the weight gain varied widely among participants, ranging from 4.3 to 13.3 kg[5].

Four months after the experiment ended, the twins' average weight was 61.7 kg, which was only 1.3 kg higher than their baseline weight of 60.4 kg, indicating they had almost returned to their original weight[1]

■Conford (University of Michigan) et. al. conducted a study in 2012 involving nine healthy, non-obese adults (seven men and two women). The participants were admitted to the hospital for two weeks, during which time they ate 4000 kcals per day (comprising 15% protein, 35% fat, and 50% carbohydrates). Their energy requirements were determined during a one-week baseline period before the start of the experiment. In addition to three main meals, they had four snacks each day. The average weight gain was 2.1 kg, of which 67 % was fat mass (FM).[6]

The summary of this review indicates that overfeeding healthy, sedentary adults with a diet moderately high in both carbohydrates and fats (35-50% energy intake each) and low in protein (11-15%) primarily results in a gain in fat mass (FM), which accounts for 60-70 % of the weight gain. Additionally, the increase in fat-free mass (FFM) may be due to an increase in body water content rather than skeletal muscle tissue. In contrast, diets with significantly increased protein intake showed favorable changes in body composition, even with increased energy intake[4]

3. Can metabolism explain this weight regain? 

Why did the participant’s weight rapidly return to normal over the ensuing weeks when they stopped overeating?

According to Dr. Bray, one of the striking findings in this Vermont study was that to maintain the weight they gained after overfeeding, they required more energy per unit surface area than before weight gain. When Dr. Bray moved to the University of California in 1970, his new lab began operating to explore his hypothesis about why extra energy was required to maintain the increased weight[1].

■Leibel (Rockefeller University) et. al. conducted a study in 1995 involving eighteen obese (BMI of 28 or higher) subjects (Group A) and twenty-three subjects who had never been obese (Group B).

They measured changes in energy expenditure under three conditions: at their usual body weight, after losing more than 10 percent of their body weight by underfeeding, and after gaining 10 percent of their body weight by overfeeding.

When maintaining a body weight at a level 10% or more below their initial weight, the total energy expenditure decreased by 8±5 kcal per kilogram per day in Group A and by 6±3 kcal in Group B.

Conversely, when maintaining a body weight at a level 10% above their initial weight, total energy expenditure increased by 8±4 kcal in Group A and by 9±7 kcal in Group B.

Changes in energy expenditure

The study concluded that maintenance of a reduced weight or elevated body weight is associated with compensatory changes in energy expenditure, which resist maintaining the altered body weight and function to restore the original weight. This suggests that the long-term effectiveness of obesity treatment through caloric reduction may be limited[7]

4. Difference Between Obesity and Overfeeding Experiments: My Thoughts

As Dr. Bray mentioned, I also believe that weight gain from temporary excessive caloric intake is due to body mechanisms entirely different from those underlying fundamental obesity. If compensatory metabolic mechanisms resist changes in body weight, why do some people continue to gain weight?


As I have repeatedly mentioned through this blog, the difference between people who are overweight and lean can be explained by the difference in set-point for body weight. (One's set-point weight goes up through intestinal starvation.) 

For example, suppose a person who normally weighs a stable sixty kg  is temporarily overfed and reaches sixty-three kg. 

This can be compared to a glass of water that is usually filled to about 97% now being filled to 100%, and then surface tension causing the water to rise above the rim. 

Conversely, maintaining a weight of fifty-six kg by eating less is like the water level temporarily decreasing, causing a dip in the surface of the water.

In both cases, the set-point weight has not changed. 

Weight gain by overeating

In contrast, if a person who originally weighs sixty kg gradually gains weight over several years, and then maintains a stable weight of ninety kg, this indicates that the set-point weight itself has increased, meaning the glass has grown larger, with energy balancing at a higher level. 

set-point weight increasing

Today, we are sometimes said to be living in an "obesogenic environment" that promotes obesity, but that does not necessarily mean consuming high-calorie foods or living sedentary lifestyles. As some researchers have already mentioned, calorie counting is clearly of little significance. Changes in caloric intake only lead to temporary weight gain or loss. 

Rader, the "obesogenic environment" in my opinion is related to foods that are overly digestible foods (refined carbohydrates, fast food, processed foods, etc.) and an imbalanced diet (lack of vegetables, etc.).
When these factors overlap with some other conditions such as skipping breakfast or eating late dinners, intestinal starvation is more likely to be induced.

Of course, researchers will say that in order to gain weight, more energy must be taken into the body than before. For more on why intestinal starvation leads to greater energy intake and weight gain, please refer to the article below.

[Related article]  Gaining Weight by Intestinal Starvation; What Does It Mean?



[1]Bray GA. The pain of weight gain: self-experimentation with overfeeding. Am J Clin Nutr. 2020 Jan 1;111(1):17-20. 

[2] Fung J, The Obesity Code, Greystone books, 2016, P114-116.

[3] Jou C. The biology and genetics of obesity--a century of inquiries. N Engl J Med. 2014 May 15;370(20):1874-7.  

[4] Leaf A, Antonio J. The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition. Int J Exerc Sci. 2017 Dec 1;10(8):1275-1296. 

[5] Bouchard C et al. The response to long-term overfeeding in identical twins. N Engl J Med. 1990 May 24;322(21):1477-82. 

[6] Cornford AS et al. Rapid development of systemic insulin resistance with overeating is not accompanied by robust changes in skeletal muscle glucose and lipid metabolism. Appl Physiol Nutr Metab. 2013 May;38(5):512-9. 

[7] Leibel RL et al. Changes in energy expenditure resulting from altered body weight. N Engl J Med. 1995 Mar 9;332(10):621-8. 




There Are Two Steps to Lose Weight the Right Way


  1. There are two ways to lose weight
  2. How to lower one's set-point weight
  3. What is your specific diet?
  4. Differences from low-carb diets
  5. The meaning of the “two-step”
    The bottom line

Although this is not a diet blog, since I’m writing the reasons why people gain weight, naturally, I thought about ways to lose weight, and I felt that I should write about it.

In this post, I will only write about my theory for losing weight. Please understand this is not based on practice, but I hope this will help someone.

1. There are two ways to lose weight

Just like the phrase “to gain weight” has two meanings, “to lose weight” also has two meanings.
【Related article】 Two Meanings to the Phrase "Gaining Weight"

 (1) In the case you rebound

The first way is done by eating less and exercising more, as in conventional calorie-restricted diets. This method requires constant hunger.

I consider that humans have an ability to maintain their present condition, and  use the "set-point" theory of body weight to explain their stable weight.

The rebound effect

When you eat less (fewer calories) and stay hungry over many hours, your body will try to minimize the change by:

  • increasing absorption rate in order to utilize maximum nutrition.
  • decreasing calorie expenditure including basal metabolism in order to suppress unnecessary consumption.

Even if you lose a little weight with your hard work, I believe it is only temporary, and most people will rebound because their set-point weight hasn’t changed.

[Related article]  Dieting Doesn’t Work in the Long Run

(2) Lower the “set-point weight” itself

The other way is to lower your set-point weight. As I have mentioned many times, the cause of being overweight, in my opinion, is an increased 'set-point' for body weight.

This means that one's absorption ability is higher than that of the average person, and I assume that the higher absorption tendency is related to symptoms such as high blood pressure, heart disease, abnormal blood sugar levels, and diabetes,etc.

So, I believe that to lose weight correctly, lowering the set-point weight itself is necessary rather than reducing caloric intake.

I will quote the reference related to this  from the book, “The Obesity Code.”


(About rebounding of weight)

"The fundamental biological principle at work here is homeostasis. There appears to be a “set point(*1) for body weight and fatness, as first proposed in 1984 by Keesey and Corbett. Homeostatic mechanisms defend this body set weight against changes, both up and down. If weight drops below body set weight, compensatory mechanisms activate to raise it. If weight goes above body set weight, compensatory mechanisms activate to lower it.

The problem in obesity is that the set point is too high. "
(Jason Fung. The Obesity Code. Greystone Books, 2016, Page 62.)

There are two prominent findings from all the dietary studies done over the years.

First: all diets work. Second: all diets fail.

What do I mean? Weight loss follows the same basic curve so familiar to dieters. Whether it is the Mediterranean, the Atkins or even the old fashioned low-fat, low-calorie, all diets in the short term seem to produce weight loss.

Sure, they differ by amount lost–some a little more, some a little less. But they all seem to work.

However, by six to twelve months, weight loss plateaus, followed by a relentless regain, despite continued dietary compliance.(*snip*)

So all diets fail. The question is why. 
Permanent weight loss is actually a two-step process. There is a short-term and a long-term (or time-dependent) problem. "

(Jason Fung. The Obesity Code. Page 215.)

2. How to lower one's set-point weight

Doctor Fung, the author of “The Obesity Code”, believes that the higher set point of body weight is  relevant to insulin resistance, which is why he has adopted fasting to cure obesity.

My opinion, which is quite different 
from other researchers, is that instead of starving ourselves, we can lower our set-point weight by eating a lot of less digestible foods, according to certain rules, which may reduce the feeling of hunger. This is because I believe that if the underlying cause of weight gain is due to the mechanism of intestinal starvation, then by doing the opposite, one should theoretically be able to lower one's set-point weight, and in turn lose weight.

fish and meat

Of all the diets that have been done , the low-carb diet (one which allows you to eat as much meat and fat as you want), the carnivore diet, the Mediterranean diet, and eating more low-G.I. foods and fibrous vegetables, etc. are all ways that fit my theory.

One might say, "I am just combining those diets.” But since the point is to leave more undigested food in the intestines, I believe they should be combined.

Note that when I say "set-point weight itself goes down," I don't mean that one's metabolism goes up, but rather that one's absorption ability itself goes down.

It may be difficult to understand how eating food reduces absorption rate, but imagine, for example, eating a snack bread and a glass of orange juice.

If you eat it when you are starving, your blood glucose level will jump up, whereas if you eat it three hours after finishing a well-balanced lunch, your blood glucose level will not rise as much.

Blood sugar spikes

Even when you go out for drinks, if you haven't eaten anything for almost ten hours, you may get drunk faster, but if you eat a good lunch and have ice cream two hours before drinking, you will get drunk more slowly. In other words, if you keep eating less digestible food to reduce hunger, the absorption rate should decrease.

3.What is your specific diet?

I think the key is to reduce carbohydrate intake to a certain extent and conversely increase meat, fish, oil/fat, fibrous vegetables, seaweed, nuts, dairy products, etc. to reduce the time you feel hungry.
(If you feel a little hungry, eat something. Eat regularly even if you don't have an appetite.) 

Specifically, I believe there are two ways to do this.

(1) The way to actually improve your diet

  • Reduce carbohydrate intake (rice, bread, noodles, etc.) by half to a third. 
  • Eat low G.I. carbohydrates if possible, such as brown rice, whole-grain bread, cold rice (starch turns indigestible once cooled down) and al dente pasta.
  • Increase foods other than carbs such as meat, fish, fat/oil, dairy products, nuts, vegetables, seaweed, etc.
  • If you feel hungry between meals, you can eat something.
  • Of course, you can combine this step with some exercise, but make sure you eat balanced meals at least three times a day.


<Regarding fat intake>

Fat is an important energy souce for the body, and at the same time a cause of weight gain for some, but I believe that it is a food that can help us lose weight depending on how we eat it.

Fat was originally thought to be fattening because of its high energy density (9 kcal/g), but in fact, since it takes longer to digest, consuming it every three to five hours can also help you to lose weight (Of course, this varies from person to person).

For those who usually eat less to lose weight, the idea that "consuming fats along with carbohydrates will make you gain weight" would not be wrong. However, what matters is how you eat it, and it cannot be judged solely by the number of calories.

[Related article]  Eating Fat/oil Is a Deterrent to Gaining Weight

(2) Slow down the digestive enzymes

For those who seem to digest food quickly no matter how much they eat, and who always feel hungry, the method (1) may not be effective. Some of them may even gain weight because of the increased calories.

I believe that the reason it becomes more difficult to lose weight as obesity levels become higher, is that they digest food faster and the absorption rate doesn't decrease so easily. In other words, the theory itself is not necessarily wrong.

In a similar case, in addition to improving the diet, it may be helpful to take medication that, for example, slows down the digestive process for fats and proteins, or decreases one’s appetite.

By slowing down the working of the gastrointestinal tract or lowering the ability to digest food, undigested food will remain longer in the intestines, which will have the same effect as (1) above.
( Naturally, it must be done under a physician's guidance.)


4. Differences from low-carb diets

Even though it is not up to extreme carb restriction (ketogenic), I believe my idea would result in a diet similar to a low-carb diet.

Those who advocate low-carb diets say, "it is the carbohydrates that cause weight gain, and instead of limiting them, you can eat as many protein-and fat-rich foods as you like to make up for the calories.”

In reality, however, it is not "you can eat" but rather "you have to" in order to lose weight.
If you reduce meat, fish, and fats/oils as well, you will feel hungry just like in a conventional calorie-restricted diet, and such diets do not work for long, as studies have shown.


My theory is that carbohydrates are only an indirect cause of weight gain making it easier to induce intestinal starvation. The point is only that we should consume more indigestible foods, which slow down the digestion process and suppress hunger. So, while carbohydrates are not necessarily bad, I believe that cutting the amount of carbohydrates in the diet will be more effective.

Of course, it is possible that reducing glucose, which provides immediate energy, may speed up weight loss in the short term.

5. The meaning of the “two-step”

For those who have been dieting by eating less, their caloric intake may at least increase . So "eat more to lose weight" may sound fishy.

However, reducing caloric intake is not the final point.

  • In the short term, the absorption rate should be temporarily reduced by eating more indigestible foods so as not to feel hungry. 
  • In the long term, it's more important, by continuing to do so, to lower one’s set-point weight and get the non-rebound body you desire.

In other words, a "two-step" process is necessary to lose weight properly.

▽In Japan, there are various ways of dieting to lose weight by eating a lot of foods, and many people have their own interpretation of “losing weight by eating a lot.”

  • Raised metabolism by eating foods.
  • Eating a lot of low-calorie foods result in reducing the total caloric intake daily.
  • Snacking results in a decrease in appetites, and as a result, reduced caloric intake at meals.
  • Some components in a specific food eaten break down(/decomposed) body fat.

Still, I believe that none of these explanations are correct (although there might be some truth in them), since “why we gain weight” is not recognized correctly and people still believe that too many calories and carbohydrates eaten are the causes of being overweight.

The bottom line

(1) Just as the phrase "to gain weight" has two meanings, "to lose weight" also has two meanings. To avoid rebounding, the set-point weight itself must be lowered.

(2) Two steps are needed to lower the set-point weight.
In the short term, eating more indigestible food and reducing hunger will lead to a temporary decrease in absorption rate.
In the long term, I believe that by continuing to do so, the set-point weight itself will drop, and the body will be less likely to rebound.

(3) In Japan, the "eat a lot and lose weight" diet is all around us, but I think it is not properly recognized, and of course, it is not officially approved as a treatment. If it is proven that intestinal starvation causes people to gain weight, I'd like to believe that the meaning of "eating a lot and losing weight" will be properly understood.


Gaining Weight by Intestinal Starvation; What Does It Mean?


  1. Hunger in Africa and hunger in the modern era
  2. Why do we gain weight during periods of starvation?
  3. What happens when one’s set-point weight is elevated?

Let me explain something about the core of this blog.
Perhaps for most of you it is hard to believe me, but I’ll just write the facts as they are, as I experienced them. I did not write this from my imagination, but based it on my own analysis of what actually happened to me.

When I got into college, my total body weight fell down to the thirty-kilo range, so I knew exactly why I gained almost five kilos so rapidly in a few days, even though I didn’t eat much.

1. Hunger in Africa and hunger in the modern era

The idea of storing fat in the body as a reserve against starvation is something every researcher considers at one time or another.

However, it is said that this theory is an idea that has been rejected by researchers throughout history. This is because many overweight people often eat more, and many African refugees are thin and malnourished. 

One might say, “If starvation makes us fat, then African refugees would be obese.”

However, please understand that this is a true state of starvation (malnutrition) in which the people can’t eat even if they want to, and I’m stating that it is different from what I call “intestinal starvation.”

African refugees do not have access to digestible food, and malnutrition even diminishes their ability to digest food and nutrients.

In contrast, many of us in developed countries are more likely to eat westernized foods made from wheat, meat, eggs, etc., which provide good nutrition and are easier to digest. Therefore, if we focus on the inner workings of our intestines, we are more prone to inducing intestinal starvation.

The reality is that being overweight has become a problem even among the poor populations in the world. What is common in these cases is not the excessive intake of calories or sugars,
but rather a diet that is low in nutritional value and unbalanced, often due to a reliance on inexpensive refined carbohydrates and a lack of vegetables.


2. Why do we gain weight during periods of starvation?

In my blog, I mentioned that one’s set-point for body weight goes up by inducing intestinal starvation, and I want to explain what it means here. For the sake of explanation, I will use plants as an example.

(1) For plants, eating food and gaining weight is done by adding "fertilizer." This fertilizer is the equivalent to our diet, and of course, we need to use fertilizer periodically for growth.

However, using too much fertilizer doesn’t usually result in producing a bigger plant, and if we use it  too often, it may sometimes have a negative effect.

The same goes for humans, and just eating a lot of calories doesn’t necessarily mean we all gain weight and become overweight. Even if we eat only one meal a day, as long as it’s well-balanced, there will be enough nutrition left in the intestines to be absorbed.

(2)Using an example of a plant, weight gain by inducing intestinal starvation and an increase in set-point for body weight could be explained in the same way as a plant that is extending its roots and taking in more nutrients. (See figure below)

When there is not enough nutrition, plants grow their roots deeper into the ground seeking more nutrients, and the same phenomenon occurs when we humans digest all the food in our entire intestines (or it may be the small intestine only),  and intestinal starvation is induced.

(It is said that “the small intestine is the second brain” or that “it has a will,” and I clearly felt the will of my small intestine.)

Actually the villi (*1) of the intestines do not grow, but the absolute level of absorption goes up by expanding the surface area over which nutrients can be absorbed. (I will explain this in greater detail to the researchers.) 

So even if you eat the same amount of food as you did before, you will gain weight instantly. (For some, it might be three kilos in a year, for others, it might be ten kilos in just a few days.) 
This, I believe, is the fundamental difference between obese and thin/lean people. 

(*1) In order to absorb more nutrients efficiently, the interior of the small intestine has a folded structure, with numerous protrusions called villi on its surface. Additionally, microvilli develop on the surface of these villi. It is sometimes said that if all of these were spread out, the surface area inside the small intestine would be equivalent to that of a tennis court.

the roots of weeds

(a:intestinal villi)

(b:The roots of a weed. They grow large without fertilizer)

There is an old Japanese saying: "You have a body that gets fat even by drinking water."

Of course, water alone does not make you fat, but I don’t think it is totally wrong. It indicates that the absorption ability of that person is that high.

3. What happens when one’s set-point weight is elevated?


(1) Once you gain weight, it becomes more difficult to lose weight

When your set-point for body weight goes up and you gain weight, it means that the balancing point, in terms of "energy- in, energy-out," has gone up, which can generate a more positive energy cycle and make it more difficult to lose weight.

When dieting, temporarily reducing the caloric intake to lose weight means reducing the "fertilizer" in the example of a plant. However, it is only a temporary weight loss, and you will likely return to your original weight when you start eating a normal diet again (the rebound effect).

Moreover, the reason why each time some people diet, they rebound and gain more weight than before is that skipping meals or eating light meals (not enough vegetables) can lead to intestinal starvation, which can further increase your set-point weight.

(2) More muscle, too

It is not that after you get fat, you gain muscle to support it. I believe that muscle is built at the same time you gained weight, at least up to a certain weight, because overall nutritional intake, including protein, has increased.

When a fat person loses body fat, the chest and thighs are thick and very muscular. After body fat is gained, would the muscles around the chest and neck thicken to support that weight?

(This varies widely from person to person.)

[Related article]
Can Thermodynamics Explain Why We Gain Weight?

(3) Cause-and-effect reverse phenomenon

The increased intake of nutrients as a whole, including protein, creates a positive cycle of energy, which leads to the following phenomena. Digestive enzymes, hormones, etc. are also made from proteins (amino acids), which may increase the ability to digest food and increase the appetite. So, it is no wonder that people with larger bodies or stronger stomachs generally eat more than others.

There exists a cause-and-effect reversal phenomenon: people do not gain weight because they eat more, but because the bigger they are, the  hungrier they become, and in turn, they eat more.

(4) Those who are overweight are prone to gaining more weight

Even if everyone eats exactly the same amount, people with big bodies-big, meaning large with some extra body fat or muscularly built-, or obese people, are more likely to feel hungry, which means that they eat relatively less, and they tend to gain more weight little by little.

It may be a vicious circle where a person eats modest amounts and gains weight, and if they skip meals or eat less to lose weight, they gain even more weight in the long run.  

【Related article】→What Does It Mean to Eat Relatively Less?

On the other hand, if a lean person eats balanced meals three times a day, every day, he or she doesn’t induce intestinal starvation. And there is a good chance they will stay the same weight and have the same appearance for the rest of their life, regardless of caloric intake.

Therefore, "fatness" and "non-fatness," in this regard, are not due to obesity genes

Also, for people like me who are very thin, being thin itself can reduce the amount of protein and other nutrients that can be taken in, thus a negative energy cycle continues. In turn, the muscles that support the stomach and intestines become weak and droopy, and the ability to digest food is also diminished by not secreting enough digestive enzymes.

This is a vicious circle where thin people can’t gain weight and remain thin.


Is Obesity a Multifactorial Disease?


  1. The view that obesity is "multifactorial" 
  2. Various factors intertwined...
    The bottom line

1. The view that obesity is "multifactorial" 

It is said that obesity is related to many factors, but why? I will quote an interesting description that is relevant to my blog.

“What causes weight gain? Contending theories abound:

・Calories ・Food reward・Food addiction
・Sugar・Sleep deprivation ・Stress
・Refined carbohydrates・Wheat
・Low fiber intake・All carbohydrates 
・Genetics・Dietary fat ・Red meat
・Poverty ・All meat
・Dairy products・Gut microbiome
・Snacking・Childhood obesity 

Childhood obesity

The various theories fight among themselves, as if they are all mutually exclusive and there is only one true cause of obesity. For example, recent trials that compare a low-calorie to a low-carbohydrate diet assume that if one is correct, the other is not. Most obesity research is conducted in this manner.

This approach is wrong, since these theories all contain some element of truth." 
(Jason Fung. The Obesity Code. Greystone Books, 2016, Page 70.)

Foods that make us fat

"THE MULTIFACTORIAL NATURE of obesity is the crucial missing link. There is no one single cause of obesity.

Do calories cause obesity? Yes, partially.
Do carbohydrates cause obesity? Yes, partially.
Does fiber protect us from obesity? Yes, partially.
Does insulin resistance cause obesity? Yes, partially. Does sugar cause obesity? Yes, partially. 


What we need is a frame work, a structure, a coherent theory to understand how all its factors fit together. Too often, our current model of obesity assumes that there is only one single true cause, and that all others are pretenders to the throne. Endless debates ensue.

Too many calories cause obesity. No, too many carbohydrates. No,
too much saturated fat. No, too much red meat. No,
too much processed foods. No, too much high fat dairy. No,
too much wheat. No, too much sugar. No,
too much highly palatable foods.No, too much eating out. No

It goes on and on. They are all partially correct.  (*snip*)

All diets work because they all address a different aspect of the disease. But none of them work for very long, because none of them address the totality of the disease.
Without understanding the multifactorial nature of obesity-which is critical -we are doomed to an endless cycle of blame."

(Jason Fung. The Obesity Code. Pages 216-217.)


I think the author provides a keen insight into the multifactorial nature of obesity. We must first understand that being overweight is not as simple as "it happens when we consume more calories than we expend," but is caused by a complex interplay of various factors.

However, what I want to say is that based on my intestinal starvation idea, the various factors can be aggregated to some extent, which means that
obesity can be complicated and intertwined with factors and theories we can see, and cannot be completely explained, but when we focus on the unseen workings of the intestines, the cause of weight gain would be mostly specific.

2. Various factors intertwined...

As I’ve already explained, please understand that the phrase “gaining weight” has two meanings.

【related article】
Two Meanings to the Phrase "Gaining Weight"

The mechanism that many people refer to as “get fat by eating a lot” is in the range of (A) in the graph below. I think that most of the Intervention studies on obesity so far have only been comparative studies that involve reducing the intake of calories, regulating the amount of carbs or fat, or increasing exercise, etc. The experiment  they are doing is also in the range of (A). 


set-point weight

Of course, everyone will lose some weight if they reduce their caloric intake and incorporate exercise, although individual differences may vary.

However, that is not the fundamental way to deal with being overweight, as Dr. Fung mentioned, so regaining weight (the rebound effect) is inevitable if you eat as before.

In contrast, when (B) the 'set-point' for body weight goes up by intestinal starvation, there are various interrelated factors.

For instance, it is said that the following affects weight gain:

・Skipping breakfast  ・Late dinner ・How many meals you eat

・Refined carbohydrates ・Processed food 

・Lack of fiber intake  ・Unbalanced diets

These are some of factors that are related to part (B) of the graph.

The important thing here is that each of these factors seems to be linked to weight gain,
but there is no causality between each factor and outcome. Rather, they are related to inducing intestinal starvation. (In this case, some may say intestinal starvation can be “confounding factors.”)


As I’ve already explained in another article, a combination of some of these factors below (from  category 1 to 4 of the table) happening simultaneously or overlapping, can cause intestinal starvation, and
the occurrence of intestinal starvation may be pinpointed in the unseen workings of the entire intestinal track (or it may be the small intestine only).

[Related article] 
Three (+one) Factors to Accelerate “Intestinal Starvation”


3 factors +1

The bottom line

(1) Many theories that are believed to make us fat fight among themselves, as if there is only one true cause of obesity, as Dr. Fung mentioned. Researchers may be well versed in their own areas of research (e.g. resistant starch, the value of eating breakfast, the effects of carbohydrate restriction, hormones, gut bacteria, etc.), but that does not necessarily capture obesity as a whole, so each theory can stand alone.

What we need now is a framework for how each theory is intertwined, and I'd like to believe my theory can be helpful in that regard.

(2) The root cause of being overweight, I believe, is the increased set-point weight, which is caused by intestinal starvation.
Intestinal starvation is caused by a combination of at least four factors, and since "what kind of food we eat" and "how we eat them (lifestyle)" are such important factors, many things seem to have something to do with weight gain-intestinal starvation can be a "confounding factor."

In other words, I believe the causes of weight gain would be mostly specific in the unseen workings of the intestines.  



Three (+one) Factors to Accelerate “Intestinal Starvation”


  1. An unbalanced diet and irregular eating rhythm can cause intestinal starvation
  2. This last, but not least important factor, what is “+one? ”

1. An unbalanced diet and irregular eating rhythm can cause intestinal starvation

I’ve stated before that what increases your set-point weight is the hunger mechanism (intestinal starvation) and here, I want to talk about three(+one) factors that accelerate intestinal starvation.
【Related article】→My Definition of “Intestinal Starvation”

In Japan, the reasons for gaining weight with the exception of calories are often said to be associated with:

an unbalanced diet
・fast food/junk food
・too many carbohydrates
・lack of vegetables, etc.

irregular eating rhythm
・eating dinner late at night
・skipping breakfast or lunch
・snacking or not

When there is only one of the situations from above, the intestinal starvation mechanism hardly occurs. However, when there are three and the +one factor which I will discuss later, the mechanism for intestinal starvation happens more often.

The 3 factors are as follows :

  1. What you eat (quality and balance of food);
  2. the time you stay very hungry between meals;
  3. the ability to digest (stomach acid, digestive enzymes, etc).

Some say they gained weight from eating too many carbohydrates, but others won’t seem to gain weight even if they eat a lot of carbs.
Some say they gained weight by eating junk foods late at night, but others don't gain at all, even if they eat in the same way.

These differences exist since intestinal starvation is decided by the composition of various factors.


Explanation of (1)

1)What you eat (quality and balance of food)
・Low fiber intake  ・Refined carbohydrates   ・Digestible protein
・Processed food  ・Fast food   ・Junk food, etc.

Meals with mainly refined carbohydrates (starch) and some good protein (a small amount is enough) and less fiber intake from vegetables, make people fat most easily. It seems with less fat in the diet, intestinal starvation is more likely to be induced. It’s because dietary fat slows digestion.

It doesn’t depend on the amount of calories you eat but the quality and balance of food you eat.

For example, eating a variety of foods and having a good balance vs a bad balance may lead to gaining weight, even if you eat in small amounts.

In contrast, balanced meals including vegetable fiber, dairy products, low G.I. foods, meat, and fat, etc., prevent inducing intestinal starvation.

*Eating speed, how many times you chew your food, or hydration during the meal, are also related to the above.

Explanation of (2)

2) The time you stay very hungry between meals
・Skipping breakfast or lunch    ・Late dinner
・Number of meals per day   ・Snacking or not

When we say we got fat due to an irregular eating rhythm such as late dinners or not eating breakfast,  it means the problem is because of the time span between meals.
In other words, experiencing being hungry for a long period of time.

Eating late at night won’t automatically make you fat. If you have to eat a late dinner, you can snack (milk, chocolates, or  sandwiches, etc.) between meals in order to prevent intestinal starvation.

Explanation of (3)

3) Digestive ability
・Strong/weak stomach    ・Gastroptosis
・Difference of digestive enzymes

Those with strong stomachs and high digestive ability tend to induce intestinal starvation more rapidly than those with slow digestion.

This is because intestinal starvation doesn’t depend on the amount of food intake, but how fast the food is processed in the entire intestinal tract (or it might be a small intestine only).

It differs from person to person, but Individuals with a droopy stomach, or poor digestion might not be able to even induce intestinal starvation.

If there are genetic factors, the difference of digestive ability will be the first thing I will bring up as the factors. And it may vary between races as well as between families. (Of course, it may change after birth.)

2. This last, but not least important factor, what is “+one ?”

I stated that an important factor other than the above three factors is “+one,” but this can be explained by a “continuity,” which is whether you had an unbalanced diet (or a light meal) for your previous meal and the meals before that.

(Japanese typical breakfast we used to eat)

For example, you eat a light meal such as a hamburger and coffee for lunch, and then you can’t eat until 9 p.m. that night.
If you had also eaten a heavy breakfast with dairy, salad, seaweed, beans, or butter, you won’t experience a intestinal starvation (it depends on the person).

The reason for this is that the intestines are as long as seven to eight meters, so it takes the food more than ten hours to pass through.

Intestinal starvation is determined by the entire intestinal tract (or it might be the small intestine only), so the previous meal or the meals before that also affect it.


My Definition of “Intestinal Starvation”

If you haven’t read these articles below, please read them first.

A Set-Point Weight; The Precondition Regarding the Rebound Effect

Two Meanings to the Phrase 'Gaining Weight'

In my previous article, "Two meanings to the phrase 'gaining weight' ," I wrote that your set-point weight increases by the hunger mechanism-strictly speaking, intestinal starvation. I would like to explain it simply.


Of course, in order to gain weight, you need nutrition such as carbohydrates, protein, or fat.

However, it’s what happens later on...because there is a time lag between the emergence of the cause of gaining weight and the actual gaining of weight by eating.

What I mention here as “intestinal starvation” is different from the situation such as when you don't eat anything over a few days.


(1) It happens when you eat and when your gastrointestinal tract is working.

(2) It refers to the situation between meals, such as between breakfast and dinner, or lunch and late dinner, or dinner and the next lunch, where every substance in the entire intestines from a range of seven to eight meters has been digested.(It might be small intestine only.)

In other words, the stomach and intestines are working to nourish the body, but all the food eaten has been digested, and the body perceives it as “there is no food.” It’s different from simple hunger in that:

 (a) basically, everything, including protein, fat, and even water, is digested;

 (b) there is no fiber or anything close to it (※This is why it is said refined carbohydrates make you fat).

▽Over the course of evolution, humans stored nutrition in the liver, bones, muscles, and fat cells in order to prepare for cases of starvation. This is because they didn’t know when they could eat the next time.

From this aspect, getting fat should be the mechanism of the body trying to store energy. Then this mechanism of storing nutrition should work strongly with those who don’t eat a lot.

However, in this era with an abundance of food, it seems like those who eat a lot are obese and those that don't eat much are thin, and this tends to lead to a misunderstanding.

There is a reason for this, and  it is my own theory based on my personal experience.
The question here is :
"In what way do our bodies perceive starvation ?" Starvation is not decided by the amount of how much we’ve eaten, but rather, how the digestion process in the intestines proceeds.

That is to say, even if you eat a lot, if your diet is skewed toward easily digestible carbohydrates and some protein, and you end up being very hungry for hours, you will be close to a starvation situation.

On the other hand, even if you eat a little, if you eat a well-balanced diet including vegetables, dairy, meat, and fat  every five to seven hours, then your body won’t perceive you as being in starvation mode. When there are some undigested substances in your intestines, your body perceives them as "there is still food." In other words, your intestines decide everything.

A long time ago, our ancestors had nuts, meat, or root vegetables, and then, even if they had nothing after that for a whole day, their bodies didn’t perceive it as starvation.

On the other hand, our current bodies sometimes  perceive us in starvation mode depending on what we eat for as little as seven to eight hours

This is an important message to convey that the increase in obesity that has been occurring worldwide since around 1980 is not necessarily due to increased caloric intake, but rather is related to (1) refined carbohydrates and easily digestible food, and (2) irregular eating habits-skipping breakfast or late night meals, etc.-associated with lifestyle changes.

[Related article] Why Does the Body Perceive That It Is More Starved than in the Past?


Two Meanings to the Phrase "Gaining Weight"


  1. When your weight goes back to your set-point weight  (A)
  2. When your set-point weight itself increases (B)

Please check out my blog below before reading this one.

→ A Set-Point Weight; The Precondition Regarding the Rebound Effect

I would like to define this term first. There are two meanings of the expression "gaining weight" which we use daily. I think the confusion of these meanings causes a lot of misunderstandings.

For example,  “you'll gain weight if you eat a lot of calories” or "despite dieting and eating less, you gain even more weight when you rebound,” etc.

I realized this when I got really thin, but I think the confusion of these two meanings results in various misunderstandings and false information, and most people are dieting in the wrong way.

1. When your weight goes back to your set-point weight  (A)

The first one is “gaining weight” meaning to go back to your set-point weight based on the mechanism of maintaining your present condition. 

set-point weight

Many of those who are overweight try to  keep their weight low by reducing their daily caloric intake and/or doing some exercise, because they do not want to gain weight.

In such cases, the body always tries to go back to its set-point. Therefore, it is no surprise that if they stop calorie restriction and return to their previous eating habits, they will gain weight. 

When people say, "If I eat high-calorie foods, I gain weight easily," or "If I eat sweets or cake, I gain weight," they are mostly talking about this meaning. 

Sometimes I hear women say, "I have a body type that gains weight easily as soon as I eat a little more."
But, in my opinion, it means that the body is repeatedly going through a “mini-diet” and a “mini-rebound” by the mechanism to preserve its current stasis.

▷Toru Watanabe, a Japanese actor, used to be heavy, but with a diet, he weighed around 70kg when he appeared on a television show.

However, when he got married at twenty-six, he couldn't maintain his diet anymore and ate a lot and he went back to 130kg. (It is said that he made a new record for his weight change every time he dieted.)

Again with the help of his wife’s home cooking, he succeeded in losing 40kg.

However, in the end, he repeated rebounding. It’s quite a famous story in Japan.
(You can imagine a glass in which water is increasing and decreasing.)

Weight gain by overeating

2. When your set-point weight itself increases (B)

On the other hand, the second “gaining weight” expression means that your set-point weight itself increases.
Though I have reduced the amount of my food intake, I shattered my previous weight level and gained three kilograms in the last year which means I’ve gained ten kilograms in the last three years... meaning my maximum weight has increased.  

set-point weight increasing

This is not due to the amount of food eaten or caloric intake, but by the mechanism of hunger (strictly speaking, I have defined it as “intestinal starvation” ).

I believe that this makes a fundamental difference between fat people and thin/lean people. (You can imagine a glass of water that the glass itself is growing larger.)

[Related article] 
My Definition of “Intestinal Starvation”

For example, someone who has never been more than sixty kilograms has become sixty-three kilograms in the last year. In this case, it means that his/her set-point weight itself increased from sixty to sixty-three kilograms.

When you gain weight to your set-point weight from a rebound after a diet, it's the (A) mechanism, but if you gain weight naturally more than your set-point weight, it is the (B) mechanism. This is because a calorie-restricted diet can create a situation of intestinal starvation.

It is generally believed in Japan that eating when your metabolism is slowing down makes you gain more weight, but it has already been proven that fat people have a higher basal metabolism[1].

■Japanese Sumo wrestlers are famous for eating a lot of rice and being fat, but I believe that, to put it in extreme terms, they will gain weight because of a mix of (A) and (B).

Although it looks like they eat more and are gaining weight, the mechanism should be the same as that of people who try dieting, but in the end, they gain more weight than before due to the rebound effect.

[1] Dr. Jason Fung, The Obesity Code, 2016, Pages 62.


The Set-Point Weight; The Precondition Regarding the Rebound Effect


  1. Each person has the ability to maintain their present condition
  2. What makes the difference of each person’s 'set-point' for body weight?

1. Each person has the ability to maintain their present condition

First of all, I want to explain the most important point. It's the assumption that each person has the ability to maintain their present condition, also known as preserving current stasis in the body.
I recognize that this is the precondition of everyone regarding weight control.

For example, there are three women:

(A) 48kg・・・who can't gain weight even if she eats a lot.
(B) 58kg・・・who can easily gain two kilos if she lets her guard down and eats a little more.
(C) 85kg・・・                   〃

All through the year, we get thinner when we are busy, and we gain a little fat when we aren’t active and eat a lot. Although everyone repeats the same pattern, even if we don't calculate calories strictly, the body shape of person won't change so easily. Fat people are fat and thin people are thin. 

In other words, I believe that each person has a stable weight based on their body's homeostatic functions, which I initially defined as their "base weight."

[Base weight] = The stable weight one returns to after spending 3-5 days relaxing without excessive exercise or work, while consuming calories based on their daily energy needs.

However, despite the lack of official proof or definition, some researchers have already used the concepts of 'set-point weight.' Additionally, my "base weight" can be confused with "baseline weight," which is used in some studies. Therefore, I will use 'set-point weight' or ‘set-point’ for body weight going forward."

In this example, Person A's set-point weight is forty-eight kilograms. However, for Persons B and C, the weights they quickly revert to when they let their guard down and eat a lot—sixty kilograms and eighty-seven kilograms, respectively—can be considered their actual set-point weight. This means that their homeostatic functions are working to maintain those weights. 

So, it’s difficult to assume a person’s body and weight condition only with caloric intake.

Consider the example above, that if A continues an intake of 100kcal over her recommended daily caloric intake every day for several months or years, the assumption is that it will accumulate into fat and she will eventually gain weight up to the eighty-kilogram level. This is wrong (She might gain weight but that is a different mechanism).


set-point weight-1
set-point weight-2

In general, people who are overweight are more likely to be restricting calories and eating modestly, so their current weight is often lower than their set-point weight. On the other hand, thin people don't have caloric restrictions, so their current weight and their set-point weight are often close

Therefore, ‘thin A’ won't gain weight even if she eats a lot, and B and C will gain weight immediately as soon as they eat a lot.

▽Example of Hozumi Hasegawa, the professional boxer who defended his title ten times as the twenty-sixth Champion of WBC World bantamweight class.

The Bantamweight limit is fifty-three-point-five kilograms(53.5kg). As his body got older, losing weight became harder. For a defending match, he had to lose more than ten kilograms in a month. 

But, as soon as the match was over and he started to eat, his weight increased ten kilograms in a few days. The rate of going back to his set-point weight was fast. Those who have tried diets and eat less than usual might have experienced this. Often, it's called the rebound effect.

2. What makes the difference of each person's 'set-point' for body weight?

According to Dr. Jason Fung, the author of “The Obesity Code,” in 1984, two researchers, Keesey and Corbett, first proposed that there is a "set point" for body weight and fatness. 

According to this idea, homeostatic mechanisms in the human body work to defend this body set weight against changes. 

Set weight

When caloric intake is reduced and weight drops below body set weight, the basal metabolism begins shutting down to conserve energy and appetite is increased, which causes body weight to return to its base.

When caloric intake is increased and weight goes above body set weight, the basal metabolism activates and the appetite decreases to lower to the original body set weight[1].

However, I have a different view about it.

It makes total sense that when the body has less energy available, it lowers its metabolism to conserve energy expenditure, and that when you eat a lot, your basal metabolism conversely increases, but isn't that a consequence of what happens in the body when you increase or decrease your intake of calories? That idea may explain the rebound effect after dieting, but it does not explain the fundamental difference between fat and lean people-the reason why some people gain weight. 

I believe that each person's ‘set-point’ for body weigh is determined by the absorption ability of the   intestines (the small intestine is also known as the "second brain”). This is my conclusion from my own experience, and I believe I can prove that theory with the help of experts.

[1] Dr. Jason Fung, The Obesity Code, 2016, Page 62