"Obese children often have obese siblings. Obese children become obese adults. Obese adults go on to have obese children. Childhood obesity is associated with a 200 percent to 400 percent increased risk of adult obesity. This is an undeniable fact. (*snip*)

Families share genetic characteristics that may lead to obesity. However, obesity has become rampant only since the 1970s. Our genes could not have changed within such a short time. Genetics can explain much of the inter-individual risk of obesity, but not why entire populations become obese.

Nonetheless, families live in the same environment, eat similar foods at similar times and have similar attitudes. Families often share cars, live in the same physical space and will be exposed to the same chemicals that may cause obesity–so-called chemical obesogens. For these reasons, many consider the current environment the major cause of obesity.

"The classic method for determining the relative impact of genetic versus environmental factors is to study adoptive families, thereby removing genetics from the equation.(*snip*)

Dr. Albert J. Stunkard performed some of the classic genetic studies of obesity. Data about biological parents is often incomplete, confidential and not easily accessible by researchers. Fortunately, Denmark has maintained a relatively complete registry of adoptions, with information on both sets of parents.

"Studying identical twins raised apart is another classic strategy to distinguish environmental and genetic factors. Identical twins share identical genetic material, and fraternal twins share 25 percent of their genes. 

In 1991, Dr. Stunkard examined sets of fraternal and identical twins in both conditions of being reared apart and reared together. Comparison of their weights would determine the effect of the different environments.

The results sent a shockwave through the obesity-research community. Approximately 70 percent of the variance in obesity is familial.(*snip*)

I think this is a very interesting study because it compared data from biological parents and adoptive parents.

However, can we assert from the results of this one alone that the influence of genetics was much greater and environmental factors were much less significant?

I believe, as Dr. Fung mentions, the rapid increase in obesity in recent years (since about 1970) has much to do with changes in our living environment (what we eat, irregular lifestyle,etc.),not the genes.

The study considers a child living with adoptive parents or twins raised separately to be a "change in living environment," but I think there is a problem with this study.

If a family can afford to take in a child as adoptive parents, don't they have some money to spare and feed their adoptee a somewhat balanced diet three times a day?
Although what they eat and caloric intake may differ from family to family, those changes don’t necessarily lead to a change in what I call their base weight. Just because the adoptive parents are thin does not mean that adoptees will become thin even if they eat the same diet.

For example, there is a Japanese comedian who is very fat (she always laughs off being fat). She didn't know breakfast existed until she was thirteen years old (because her mother never made it at all), but what if such a family were her adoptive parents?
If a child is adopted into such an extreme family, it may well affect their weight in the long run, but if they are in a family that feeds them a standard diet three times a day, It can’t be said that it is a "change in environment."

In Japan in the past few decades, our traditional eating habits have been declining. Instead, our diet has become more westernized and our ways of working have become more diverse.
When some of these conditions such as not eating breakfast or lunch, eating late at night, fast food, not eating vegetables, carbohydrate-dense food, etc. are combined, intestinal starvation may be induced and lead to an increase in base weight.

This is the "environmental factors and human behaviors" for recent obesity epidemic, I want to say, and I believe that environmental factors has more influence than genetics. (Of course, genetic factors cannot be ignored).

But, I’m simply wondering what the childhood body shape is due to? Whether it is genetic factors or the way food is prepared during childhood－including weaning－is a question that remains unanswered.
   

(1) In a study regarding adoptive families and examining how genetic and environmental factors influence being overweight, no correlation was found between the weight of adoptive parents and that of their adoptees. On the other hand, when the adoptees were compared to their biological parents, there was a consistent correlation between the weight of both.

A study of twins raised separately also concluded that "genetic influences are far more significant.”

(2) Many researchers had previously blamed "environmental factors and individual behavior” for the recent obesity epidemic, but this study concluded that genetics had far more impact than environmental factors.

However, I find this study problematic. The fact of children living with adoptive parents or twins raised separately is not necessary an environmental factor that causes changes in weight.

(3) Of course, I do not think we can ignore the genetic factor, but I believe that the recent obesity epidemic is caused by a combination of what we eat－westernized diets, refined carbohydrates, processed foods, etc.－plus lifestyle changes. 

A major change in weight and body shape occurs when one’s base weight value goes up, which is induced by intestinal starvation. It requires (three + one) factors for that to occur.

(4) If there is no significant change in base weight, I think the body shape from childhood is expected to continue. However, I 'm uncertain what determines childhood body shape, whether it is heredity or the way food is prepared during childhood, including weaning.
     

■The 1970s, when the dining scene changed dramatically

I think it was after 1970 that our dining landscape slowly changed. I had not been taken to restaurants much when I was a kid, but fast food restaurants and other restaurant chains opened one after another in all corners of Japan, and many people began to eat Western food.

McDonald's (since 1971), Kentucky Fried Chicken (since 1970) and family restaurants called Skylark (since 1970) were the most famous among them. In 1974, the first convenience stores (called Seven-Eleven) opened in Tokyo, followed by a rapid increase throughout the country. Instant foods such as cup noodles and frozen foods also increased rapidly, reflecting busy social conditions.

Our lifestyles also changed dramatically. More and more people began to work at desks rather than at physical jobs. Nighttime lifestyles became the norm, and more people didn't even eat breakfast.

It was probably around this time that obesity began to increase in Japan. Nowadays, it is not unusual to see women over one hundred-kilograms on the streets.

As an example of how obesity has increased as old traditional eating habits have declined and became westernized, I would like to cite a Native American tribe known as the Pima, although the situation is slightly different.
This is the second time I quote from Mr. Taubes' "Why We Get Fat," but this part is very important and may be the key to solving the problems of obesity, diabetes, and other diseases.
    

"Consider a Native American tribe in Arizona known as the Pima. Today the Pima may have the highest incidence of obesity and diabetes in the United States. Their plight is often evoked as an example of what happens when a traditional culture runs afoul of the toxic environment of modern America. (*snip*)

Between 1901 and 1905, two anthropologists(Russell and Hrdlička) independently studied the Pima, and both commented on how fat they were, particularly the women. (*snip)

Through the 1850s, the Pima had been extraordinarily successful hunters and farmers. 

     
[Related article] Wealthy Ones Get Fat? Poor Ones Get Fat?

In terms of food, I believe that Japanese people in 1970 were eating a lot of different kinds of food than today. There were no convenience stores, and the diet was based on mom's home cooking, with a variety of seasonal vegetables and fish.

In contrast, the modern diet is based on easily digestible carbohydrates and meat, and the variety of food ingredients we eat seems to have decreased dramatically. Many people are normally worried about gaining weight and are dieting, and then they occasionally splurge and eat high-calorie food as a reward. The situation is different, but if we focus on the inside of the intestines, I can say that it is the same as what happened to the Pima population.

     
I believe what the author tried to get across was that the modern diet of allowing large amounts of carbohydrates is not genetically compatible with our bodies, and that eating meat and its fat may be more compatible and less harmful to us on a genetic level.

I will quote this passage above to explain my intestinal starvation mechanism.

Suppose (and it makes more sense) that God created a genetic blueprint for people to "store body fat" in case they could not find food. 

In contrast, a modern diet high in refined wheat/rice, starch, easily digestible protein, and processed foods can lead to intestinal starvation even in just half a day. I believe it is the entire intestines (or it may be the small intestine only) that makes all the decisions, and it goes to show that inside the gut, many of us are  starving more today than in the past.
      

References：
[1]Yasuo Kagawa(香川靖雄) , Clock Gene Diet (時計遺伝子ダイエット), 2012, Page 15.

People sometimes say, "Japanese food culture is healthy by world standards," but I believe this to be a relic of the past until around the year 2010 at the latest. Now, I feel that traditional Japanese food culture is dying in the average household.

Children who grew up eating fast food are now in their fifties and sixties, and their children are now in their thirties. Thus, in about fifty to sixty years (about two generations), the opportunity to eat traditional foods will have faded away, and the food culture will change greatly.

And, with the shift in diet, it seems like that diseases such as diabetes, kidney disease, heart disease, cancer, and stroke, which were once not as common, are on the rise, just as they are in the Western countries.
    

First, please read the following article. 
The Calorie Principle and Weight Gain; The Causality Has Been Obscure

According to Gary Taubes, the author of Why We Get Fat, it was first claimed in the early 1900’s by Carl von Noorden (a German diabetes specialist) that we gain weight because we take in more calories than we expend. This argument has continued to the present day, and we are told that taking in too many calories and/or lack of exercise are the causes of weight gain. 

This time, I would like to share the “law of thermodynamics,” which was said to be the basis for that theory. Mainly quoted from the book, it is so interesting that I think it is worth reading.
  

Because all mass－our fat tissue, our muscles, our bones, our organs, a planet or star, Oprah Winfrey－is composed of energy, another way to say this is that we can't make something out of nothing or nothing out of something.

This is so simple that the problem with how the experts interpret the law begins to become obvious.

All the first law says is that if something gets more or less massive, then more energy or less energy has to enter it than leave it.

It says nothing about why this happens. It says nothing about cause and effect. It doesn't tell us why anything happens; it only tells us what has to happen if that thing does happen. A logician would say that it contains no causal information.（*snip*)

If you asked me this question, and I said, Well, because more people entered the room than left it, you'd probably think I was being a wise guy or an idiot. Of course more people entered than left, you'd say. That's obvious. But why? And, in fact, saying that a room gets crowded because more people are entering than leaving it is redundant－saying the same thing in two different ways－and so meaningless.

Now, borrowing the logic of the conventional wisdom of obesity, I want to clarify this point. So I say, Listen, those rooms that have more people enter them than leave them will become more crowded. There's no getting around the laws of thermodynamics. You'd still say, Yes, but so what? Or at least I hope you would, because I still haven't given you any causal information. 

This is what happens when thermodynamics is used to conclude that overeating makes us fat. （*snip*)

"The first law states that energy can neither be created nor destroyed. In other words, energy can be converted from one form to another, but the total amount of energy in the universe remains constant. How might this law apply to weight management?

Suppose someone has stable weight over time. The first law dictates that, in theory, the number of calories consumed by this individual in the form of food is equal to the calories the individual expends during metabolism and activity. In other words, 'calories in = calories out’.(*snip*)

However, the first law of thermodynamics actually refers to what are known as ‘closed systems' －ones that can exchange heat and energy with their surroundings, but not matter. Is this true for human beings? 

Two authors have made excellent points about the relationship between thermodynamics and weight management. Based on those thoughts, I would also like to mention two points about the relationship between thermodynamics and my theory.
  

(1)What constitutes "caloric intake" 

I also basically believe that if a person has a stable weight over the years, then "the energy consumed  and the energy expended for basal metabolism and activity,etc." must be balanced.
The question, however, is: at what point have we "taken in" energy? 

▽Let's take the example of calcium in milk.

From experience, we know that it is not always true that the more milk we drink, the more calcium we take in and the stronger our bones will become.

Just because a bedridden old lady drinks five glasses of milk a day every two hours every day, does not make her bones stronger; in fact, it sometimes has the opposite effect. Even with just a glass or two of milk a day, exercising more and feeling hungry can increase absorption rate and make her bones stronger. 

(2) When energy intake increases

Based on my intestinal starvation mechanism concept, even if a person who has maintained the same weight over the years, significantly reduces their usual caloric intake (e.g. about two thousand kcal daily) and the intake of carbohydrates, but meets the "three factors + one" criteria that cause intestinal starvation, they will gain weight (this means an increase in base weight).

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

Of course, weight gain mostly occurs when the person then goes back to the original diet, but in this case, absorption ability itself goes up, meaning that not only body fat, but also blood and muscle mass,etc. increase, resulting in "weight gain."

In short, even though you are eating the same amount of food (calories) as before, you are taking in more energy and nutrients into your body than before, which means you are getting bigger/fatter. In the words of Gary Taubes, "a room crowded with ten people now has eleven people," and in this case, it is “intestinal starvation” that has caused it.
  

(1) It's the law of energy conservation (the first law of thermodynamics) that experts believe that the cause of obesity is due to an " imbalance of calories ingested or expended.

(2)Since the human body is a mass of chemical reactions and not a "closed system," it does not make sense to compare the total calories actually eaten with the calories expended. In this case, the "law of thermodynamics" does not hold.

(3) If we base it on the calories actually absorbed in the intestines, it should be closer to a "closed system" and be balanced with the calories expended through one’s basal metabolism and activity,etc.

(4) If intestinal starvation is induced and your base weight goes up, you will gain weight even if you are eating the same amount as before, which means that the energy taken into the body has increased. Since the absorption ability itself has gone up, the increase in body weight is related to not only body fat, but also blood and muscle mass,etc.

In Japan, most people believe that “taking in too many calories and lack of exercise are the causes of being overweight,” which I believe is largely due to statements made by experts, nutritionists, etc. on television.

When I launched this website in 2014, I wanted to argue against that in my website, but I couldn’t find any academic papers and other resources that showed the "causal relationship between caloric intake and becoming obese." 

However, around a year after I started blogging, I came across this great book: “Why We Get Fat” written by Gary Taubes. It is surprising that it was published in Japanese in 2013.

After all, this is the only book I can rely on. In explaining what I want to say, I first needed to let you know that, "the direct cause of being overweight is not determined by overeating.”

Arguing to the contrary, that we might actually get fatter for reasons other than the twin sins of overeating and sedentary behavior, or that we might lose fat without consciously eating less and/or exercising more, has invariably been treated as quackery－ "emotional and groundless," as the Columbia University physician John Taggart insisted in the 1950s in his introduction to a symposium on obesity. “We have implicit faith in the validity of the first law of thermodynamics," he added.

(*snip*)
"In 1934, a German pediatrician named Hilde Bruch moved to America, settled in New York city. She was “startled,” as she later wrote, by the number of fat children she saw－”really fat one, not only in the clinics, but also on the streets, subways, and in schools.” This was two decades before the first McDonald's franchises was born, and more to the point, 1934 was in the depths of the Great Depression.

Bruch put in effort in the treatment of obese children. It was hard to avoid, she said, the simple fact that these children had, after all, spent their entire lives trying to eat in moderation and control their weight as directed, and yet they remained obese.

▽“The fundamental cause of obesity and overweight," as the World Health Organization says, “is an energy imbalance between calories consumed on one hand, and calories expended on the other hand." 

This way of thinking about our weight is so compelling and so pervasive that it is virtually impossible nowadays not to believe it. Even if we have plenty of evidence to the contrary－no matter how much of our lives we've spent consciously trying to eat less and exercise more without success— it's more likely that we'll question our own judgment and our own willpower than we will this notion that our adiposity is determined by how many calories we consume and expend."
(Taubes. Why We Get Fat. Pages 3-6.)

Throughout the decades of this obesity epidemic, the calories-in/calories-out, energy-balance notion has held sway, and so the health officials assume that either we're not paying attention to what they've been telling us －eat less and exercise more－or we just can't help ourselves.

Malcolm Gladwell discussed this paradox in The New Yorker in 1998.
“We have been told that we must not take in more calories than we burn, that we cannot lose weight if we don't exercise consistently," he wrote. “That few of us are able to actually follow this advice is either our fault or the fault of the advice. Medical orthodoxy, naturally, tends toward the former position. Diet books tend toward the latter. Given how often the medical orthodoxy has been wrong in the past, that position is not, on its face, irrational. It's worth finding out whether it is true.”
(Taubes. Why We Get Fat. Pages 7-8.)

Japanese television programs still continue to show doctors and nutritionists confidently saying, "The cause of weight gain is, of course, overeating or lack of exercise,”which I find disgusting. However, I hope you can see how flimsy and baseless these theories are.

By the way, I obtained Carl von Noorden's book (archive), which is shown at the beginning of the quotation. You can read it at the following link: 

 Carl von Noorden's book
  

Most of the parts of this article are citations from a book, but at the end of this article, I will explain how it is related to my experience.

[Related article]　→ Wealthy Ones Get Fat? Poor Ones Get Fat?

"This combination of obesity and malnutrition or undernutrition (not enough calories) existing in the same populations is something that authorities today talk about as though it were a new phenomenon, but it's not. Here we have malnutrition or undernutrition coexisting with obesity in the same population eighty years ago."
(Gary Taubes. Why We Get Fat. New York: Anchor Books, 2011, Page 24.)

(In the mid-1930s, New York City)

"In 1934, a young German pediatrician named Hilde Bruch moved to America, settled in New York city, and was “startled,” as she later wrote, by the number of fat children she saw—“really fat ones, not only in clinics, but on the streets and subways, and in schools. (*snip*)

(The case of a native American tribe, the Sioux, in 1930's)

Two researchers from the University of Chicago studied Native American tribe, the Sioux living on the South Dakota Crow Creek Reservation. These Sioux lived in shacks “unfit for occupancy,” often four to eight family members per room. Fifteen families, with thirty-two children among them, lived “chiefly on bread and coffee.” This was poverty almost beyond our imagination today.

Yet their obesity rates were not much different from what we have today in the midst of our epidemic: 40 percent of the adult women on the reservation, more than a quarter of the men, and 10 percent of the children, according to the University of Chicago report, “would be termed distinctly fat.”

(In the slums of São Paulo, Brazil)

"This is from a 2005 New England Journal of Medicine article, “A Nutrition Paradox-Underweight and Obesity in Developing Countries,” written by Benjamin Caballero, head of the Center for Human Nutrition at Johns Hopkins University.

Caballero describes his visit to a clinic in the slums of São Paulo, Brazil. 

Caballero then describes the difficulty that he believed this phenomenon presents: “The coexistence of underweight and overweight poses a challenge to public health programs, since the aims of programs to reduce undernutrition are obviously in conflict with those for obesity prevention.”

Put simply, if we want to prevent obesity, we have to get people to eat less, but if we want to prevent undernutrition, we have to make more food available. What do we do?"
 (Taubes. Why We Get Fat. Pages 30-1.)

"In the early 1970s, nutritionists and research-minded physicians would discuss the observations of high levels of obesity in these poor populations, and they would occasionally do so with an open mind as to the cause. (*snip*)

Malnutrition and subnutrition are common disorders in the first two years of life in these areas, and account for almost 25 per cent of all admissions to pediatric wards in Jamaica. Subnutrition continues in early childhood to the early teens. Obesity begins to manifest itself in the female population from the 25th year of life and reaches enormous proportions from 30 onwards.”

<About undernutrition and overweight>

First, I would like to explain, based on my experience, that the coexistence of undernutrition and obesity are not contradictory messages.

I repeat that when I was very thin, under forty kilograms, at first, I was eating  high-calorie foods such as deep-fried foods or sweet, but I couldn’t gain weight. And then, I realized that I could gain weight by digesting all the foods in my whole intestines and inducing intestinal starvation.

The easiest way to induce intestinal starvation was to eat refined carbohydrates (starches) and a little easy-to-digest protein (and not to eat other foods), but since it lacked energy and essential nutrients for my body, I felt dizzy from the undernutrition. 

In short, a higher ratio of carbs in the meal (not an amount of carbs) and eating fewer fibrous vegetables and nutritious foods are more likely to induce intestinal starvation and cause you to gain weight. It’s probably certain that a deficiency of vitamins and/or minerals can cause illnesses, but being overweight is not contradicting being in a state of undernutrition.
  

<About the coexistence of being underweight and overweight>

Getting back to what Caballero refered to, even if people eat similar foods in the same group, it may lead to a different result in the body.
Some people who digested all the foods in their whole intestines may have gained weight—which means their base weight value went up by intestinal starvation— and ended up becoming overweight. 

However, those who were not able to digest all the foods in their whole intestines remained underweight. I believe that leaving Just a little bit of undigested food in the intestines makes it hard to induce intestinal starvation. (Being extremely thin can cause poor digestion, so it makes it harder for them to induce intestinal starvation.) A small difference sometimes makes a big difference in the end result.

Most researchers just try to fit everything into the theory that “fat people eat too much or are physically inactive” for some reason.

However, if we look at these ideas I’ve presented with an open mind, we can say that this is the same phenomenon as the "coexistence of thin and obese" in the same population. At the risk of repeating myself, being overweight is not necessarily the consequence of overeating.