The Atkins diet is a type of low-carbohydrate diet proposed by cardiologist Robert Atkins that restricts the amount of carbohydrates for energy and instead uses "fat" as an energy source. It is characterized by limiting carbohydrates to twenty to twenty-five grams per day for the first two weeks and then gradually increasing.

According to Dr. Fung, the author of “The Obesity Code,” Dr. Atkins weighed nearly one-hundred kilograms in 1963, and when he began working as a cardiologist in New York City, he needed to lose weight. 

However, he couldn’t lose weight successfully on a conventional calorie-restricted diet, so he tried the low-carb diet based on the medical literature, which worked well as advertised, and he recommended it to his patients. 

New studies started appearing around 2005, comparing the Atkins diet to other diets that were once considered the standard, and what were the results?[1]

Let's take a look. I would like to express my thoughts on this at the end of this article. 

"In 2007, the Journal of the American Medical Association published a more detailed study: Four different popular weight plans were compared in a head-to-head trial.

One clear winner emerged-the Atkins diet. The other three diets (Ornish, which has very low fat; the Zone, which balances protein, carbohydrates and fat in a 30:40:20 ratio; and a standard low-fat diet) were fairly similar with regard to weight loss. 

While the Mediterranean diet held its own against the powerful, fat-reducing Atkins diet, the low-fat AHA standard was left choking in the dust–sad, tired and unloved, except by academic physicians.[2]" 

"Longer-term studies of the Atkins diet failed to confirm the much hoped-for benefits.
Dr. Gary Foster from Temple University published two-year results showing that both the low-fat and the Atkins groups had lost but then regained weight at virtually the same rate. (*snip*) 

A systematic review of all the dietary trials showed that much of the benefits of a low-carbohydrate approach evaporated after one year.

These foods are clearly fattening, no matter what diet you believe in. We continue to eat them simply because they are indulgent. (*snip*)The Atkins diet does not allow for this simple fact, and that doomed it to failure.

The first-hand experience of many people confirmed that the Atkins diet was not a lasting one. Millions of people abandoned the Atkins approach, and the New Diet Revolution faded into just another dietary fad. (The company Dr. Atkins founded in 1989 went bankrupt.)

But why? What happened?
One of the founding principles of the low-carbohydrate approach is that dietary carbohydrates increase blood sugars the most. High blood sugars lead to high insulin. High insulin is the key driver of obesity. Those facts seem reasonable enough. What was wrong?[3]"

Experts who advocate low-carbohydrate diets seem to think that carbohydrates cause weight gain because they eventually stimulate insulin secretion.

However, Dr. Fung mentioned that the carbohydrate-insulin hypothesis is incomplete. Various problems are cited, but he raised the "paradox of the Asian rice eater" and the "diet of Kitava Island, in Papua New Guinea" as notable examples.  

Most Asians have been eating a diet based on refined rice as their staple food for at least the last five decades; a study conducted in the late 1990’s found that carbohydrate intake in China and Japan was similar to or rather, higher than in the U.K. and the U.S. 

Since Dr. Fung just mentioned the paradox of the Asian rice eater, I would like to mention this.

I am Japanese and was born in 1970, and I think that I should know how our diet has changed in the last five decades, and as a result, how obesity has increased in our society. 
(This is explained in more detail in the following blog.)

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

In short, I believe that carbohydrates are a contributing cause, but not the quantity itself.
Japan was basically an agrarian society, and rice cultivation has always been important. Until at least 40-50 years ago, I believe most Japanese people had eaten a lot of rice as it is called the staple food, but at the same time, they also ate a lot of fibrous vegetable dishes using roots or stems of plants, fermented soybean product called “natto,” and fish and meat dishes. Rice cakes called “mochi” and Japanese sweets as well.

At least in my family, my father was strict about family members eating meals three times a day at a regular time, every day.
  

I believe that the "three factors plus one" of my intestinal starvation theory can explain how the various factors intertwine, and how weight gain occurs. It's not just the amount of carbs eaten that matter.

The "Do calories make people fat, or carbs?" concept is said to be a debate that has been going on since the 1800’s [5], and I think both are true in some ways, but neither is perfect.

If you reduce the amount of any energy source beyond what your body needs, it’s obvious that you will lose weight in the short term. However, if you go back to your original diet, in the long run, you will also regain the weight you had lost, as various studies have confirmed, and as most people who have been on a diet have probably realized.

The reason for this is that the human body, I believe, basically works to maintain the status quo. I introduced "base weight" to describe the body weight based on that. So, the point is that in order to avoid rebounding, you must lower your base weight itself. 
(For more information on how to do this, please see the following article.)

[Related article]  There Are Two Steps to Lose Weight the Right Way

In terms of this rebound in the Atkins diet in section three, I don't think it necessarily means that low-carb diets, including Atkins, are ineffective. I’m positive that it’s the one of the correct ways to lose weight.

However, if we focus too much on blood sugar and insulin levels, we lose sight of another important point.

What I mean is that, the point of a low-carb diet, I believe, is not only the reduced carbohydrate amount, but also "how we increase the amount of other indigestible foods including meat, fat, fibrous vegetables, dairy products, etc." By sending plenty of indigestible foods to the gastrointestinal tract, we should feel less hunger and, in turn, the absorption rate should decrease. In particular, fats and oils in the diet should not be reduced, but rather should be consumed at every meal and even when having snacks.

From that point of view, I think that dieticians did not need to ban sweets such as chocolate, candy, ice cream, etc. so strictly. What is important is to be able to have them occasionally and not be too hard on yourself.

<Reference>
[1] Dr. Jason Fung, The Obesity Code, 2016, Pages 96-99.
[2][3] Pages 100-103.
[4] Pages 103-105.
[5] Gary Taubes, Why We Get Fat, 2011, Pages 148-162.

(1) In the early 2000’s, the Atkins diet became a huge trend in the U.S., inspired by the low-carb diet that was rekindled in the 1990’s. In the short term, the Atkins method not only helped people lose weight, but it also significantly improved blood pressure, cholesterol, and blood glucose levels.

(2) However, in long-term studies, the subjects rebounded, as seen with low-fat diets. After one year from the end of the study, all the benefits of Atkins diets were gone.
Dr. Fung considered the "carbohydrate-insulin hypothesis" an incomplete theory. Carbohydrate intake itself was not the problem.

(3) My thoughts. If there is no change in your base weight, rebound can occur if you eat as you used to. In order to lose weight correctly, your base weight itself needs to be lowered.

(4) The point of a low-carbohydrate diet is not just  the amount of insulin secreted. I believe that it’s rather important to "take in more indigestible foods other than carbohydrates, and not feel hungry." 

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.[1]

(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*)

One in every four workers in the United States was unemployed. Six out of every ten Americans were living in poverty. In New York City, where Bruch and her fellow immigrants were astonished by the adiposity of the local children, one in four children were said to be malnourished. How could this be?(*snip*)

It was hard to avoid, Bruch said, the simple fact that these children had, after all, spent their entire lives trying to eat in moderation and so control their weight, or at least thinking about eating less than they did, and yet they remained obese.[2]
     

(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.”

The diets on the reservation, much of which, once again, came from government rations, were deficient in calories, as well as protein and essential vitamins and minerals. The impact of these dietary deficiencies was hard to miss: “Although no counts were taken, even a casual observer could not fail to note the great prevalence of decayed teeth, of bow legs, and of sore eyes and blindness among these families.[3]
     

(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?[4]
    

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.”

Referring to obesity as a “form of malnutrition” comes with no moral judgments attached, no belief system, no veiled insinuations of gluttony and sloth. It merely says that something is wrong with the food supply and it might behoove us to find out what.(*snip*)

Again, the coexistence of underweight and overweight in the same populations and even in the same families doesn't pose a challenge to public-health programs; it poses a challenge to our beliefs about the cause of obesity and overweight.[5]"
      

References：
[1](Gary Taubes, Why We Get Fat, 2010, Pages 24)
[2] P. 3, 4
[3] P. 23,24
[4] P. 30,31
[5] P. 29-32

<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. 

When we consider that “eating a lot leads to gaining weight,” I believe you have the image of carbohydrates like bread, rice, and noodles in mind.

Thus, in the case of brown rice, fried rice, whole-grain bread, cold rice, and al dente cooked pasta, etc., the result may be different, even though they are the same type of carbohydrates. These are known as foods that won’t increase blood sugar levels much (low glycemic index, resistant starches) but in short, they are indigestible.
  

I’m simply saying that it is hard to gain weight if a thin person eats them properly every day.
Although a person who has already gained weight (or who is already overweight) may not lose weight by eating some indigestible foods, I consider that it may be possible to lose weight depending on how you eat them, since these foods are always discussed in dieting techniques.
  

On the contrarily, refined digestible carbohydrates (rice, rice porridge, white bread, potatoes, starches, etc.) will promote digestion. By eating them together with digestible proteins, they make it easier to  induce intestinal starvation. Those are two effects that I can think of so far.
    

If you proportionally increase digestible carbohydrates in the meal, the percentage of side dishes such as fat, meat, fish, and vegetables will be relatively smaller. The density of a spoonful of oil will be lower if you eat more bread or rice portions with soup (water). 

Moreover, as seen in low-carb diets, what would happen if you decrease the intake of carbohydrates  in the meal and instead increase proteins such as meat and fish, fat, and vegetables? 

In this case, the opposite effect of the dilution effect occurs: dense nutrients are delivered to the intestines, which slows digestion and undigested food always remains in the gastrointestinal tract.
    

When we eat carbohydrates together with water, our stomach expands (I’ll call this the “balloon effect” of the stomach). And, if we eat carbs together with digestible side dishes such as stew (onion, potatoes, low-fat chicken, etc.), its holding time in the gut will be shorter since it’s easy to digest, and the food will be pushed out of the stomach fairly soon. Also, our intestines start to move actively and smoothly.

On the other hand, you may think that eating fatty foods or deep-fried foods give us stamina. It actually means that those foods fill us up better than carbs do, and its energy could be sustained during sports such as a marathon or a soccer match.
That is to say, undigested foods stay longer in our stomach and intestines, so it’s more difficult to induce intestinal starvation.

(1) Simply put, poorly digestible foods are not fattening. In contrast, refined grains, starches, and other easily digestible carbohydrates tend to make people fat. These polysaccharides may have a "dilution effect" or "push-out effect" in the digestive process.

(2)I consider sugar (monosaccharides, disaccharides) and polysaccharides (starch, flour, rice, etc.) can not be put into the same category since they have different characteristics based on my theory. Recent popular low-carb diets focus primarily on the blood glucose-raising properties of carbohydrates, which alone is not a sufficient explanation for why it is necessary to add more meat, fat, vegetables, and other side dishes in the diets.

(3) Obesity among poverty-stricken people worldwide can be understood as the influence of cheap refined carbohydrates and unbalanced diets (lack of vegetables, etc.). Considering them, it may be easier to imagine that they are not gaining weight due to taking too many calories or sugar, but rather from consuming cheap carbohydrates as mentioned above.
[Related article] Wealthy People Get Fat? Poor People Get Fat?

(4) Also, the fact that sumo (Japanese national sports) wrestlers eat digestible hot pot dishes called “chanko” with a lot of rice two times a day in order to make their bodies larger is a very logical view in this sense.

First, as many of you know, even carbohydrates contain four kcal of energy per gram. So, some readers may think, "After all, isn't being overweight ultimately caused by too many calories?"

But if you think, "too many calories are the cause," you should try to reduce the total amount of calories in your overall diet, mostly focusing on fat/oil intake, which has nine kcal per gram.

On the other hand, the argument that “too many carbohydrates cause weight gain” allows you to eat any amount of meat and fatty/oily foods as long as you cut back on carbs.

In this article, I will look back on the historical argument of whether carbohydrates or calories are the cause of weight gain, and at the end of this article, I would like to share my thoughts.

In Japan, a low-carb diet was trendy around 2015, but when we look around the world, this way was repeatedly conducted since the 1800’s. Please note that there are many quoted parts. I needed to share this information with you to explain my theory.
  

"Jean Anthelme Brillat-Savarin was born in 1755. (*snip*) His passion, though, was always food and drink, or what he called the “pleasures of the table.” He began writing down his thoughts on the subject in the 1790s; Brillat-Savarin published them in a book, The Physiology of Taste, in December 1825. (*snip*)

“Tell me what you eat,” Brillat-Savarin memorably wrote, “and I shall tell you what you are." (*snip*)

Over the course of thirty years, he wrote, he had held more than five hundred conversations with dinner companions who were “threatened or afflicted with obesity,” one “fat man” after another, declaring their devotion to bread, rice, pasta, and potatoes. This led Brillat-Savarin to conclude that the roots of obesity were obvious. 

・By the time, a French physician and retired military surgeon named Jean-Francois Dancel had come to the same conclusions as his countryman Brillat-Savarin. Dancel  presented his thoughts on obesity in 1844 to the French Academy of Sciences and then published a book, Obesity, or Excessive Corpulence: The Various Causes and the Rational Means of a Cure.

Dancel claimed that he could cure obesity “without a single exception” if he could induce his patients to live “chiefly upon meat," and partake “only of a small quantity of other food." 

Dancel argued that physicians of his era believed obesity to be incurable because the diets they prescribed to cure it were precisely those that happened to cause it. (*snip*)

▽Until the early years of the twentieth century, physicians typically considered obesity a disease, and a virtually incurable one, against which, as with cancer, it was reasonable to try anything. Inducing patients to eat less and/or exercise more was just one of many treatments that might be considered. (*snip*)
    

(1950's)
The effects of a carbohydrate-restricted diets were then confirmed in the 1950s by Margaret Ohlson, head of the nutrition department at Michigan State University, and by her student Charlotte Young.

The reports continued into the 1970s. (*snip*)

The diets were prescribed for obese adults and children, for men and women, and the result were invariably the same. The dieters lost weight with little effort and felt little or no hunger while doing so."[3]

As you can see, by cutting back on carbohydrates and eating more of other foods such as meat and greasy food, the problem of being overweight seems to be solved...but this is where the "calorie principle" comes into play. 
   

"By the 1960s, obesity had come to be perceived as an eating disorder. (*snip*)

 Adiposity 101 was discussed in the physiology, endocrinology, and biochemistry journals, but rarely crossed over into the medical journals or the literature on obesity itself. 

When it did, as in a lengthy article in The Journal of the American Medical Association in 1963, it was ignored. Few doctors were willing to accept a cure for obesity predicated on the notion that fat people can eat large portions of any food, let alone as much as they want. This simply ran contrary to what had now come to be accepted as the obvious reason why fat people get fat to begin with, that they eat too much. 

References：
[1](Gary Taubes, Why We Get Fat, 2010, Pages 148-149)
[2] P. 151, 152
[3] P. 151, 157-158
[4] P. 159,160
[5] P. 161

I ‘d like to talk about this controversy.

Several studies have shown that how we combine the three macronutrients (protein, fat, and carbohydrates) in the diet produces different results in body fat accumulation. It is thought that even the same one calorie has different energy used for digestion and absorption, different hormones to stimulate, and different pathways of how the calorie is metabolized in the body.

Of course I think these studies are great, but the point I'd like to add based on my theory is that "carbohydrates and fat are close to having opposite properties in their digestive processes."

First, refined carbohydrates are more easily digested than meats and fats, and the "dilution effect" or "push-out effect" they have makes our digestion go even faster and makes us feel hungrier.

If we eat an unbalanced diet that lacks vegetables, fat, and dairy products,etc., we are ultimately more prone to inducing intestinal starvation.

That is to say, depending on how we structure our diets, there may be a weight-loss effect even with increased caloric intake (for those who can digest protein and fat quickly, the weight-loss effect may be less pronounced) .
   

・From the early 1800’s through the 1960’s, several studies had shown that overweight people could lose weight without difficulty by replacing some carbohydrates in their diet with a lot of meat and fat. By that time, however, obesity was understood as an eating disorder, and this diet method was discussed only in physiology, endocrinology, etc.

・From the 1960’s to the late 1970’s, few physicians accepted the idea that fat people could lose weight by eating lots of meat and fat, because it obviously violated the "calorie principle.”

・In addition, health experts came to believe that fat in the diet caused heart disease and that carbohydrates were "heart-healthy." As a result, doctors and nutritionists began attacking low-carb diets.

・My thoughts: Both sides have a point, but the caloric intake does not determine everything. Different combinations of foods, even with the same calories, have different effects on weight management. In particular, carbohydrates and fat are close to having opposite properties in their digestive processes.

In Japan, since around 2015, the low-carb diet－we call "Locabo" based on the English term "a low-carb"－has been catching on among many people. Japan is traditionally a rice-eating culture, but after World War II, more and more people preferred bread and noodles, and with increasingly westernized diets, many feel that we are gaining weight as well. 

This time, I’d like to introduce the Locabo diet in Japan and Sugar Busters in the U.S., which is believed to be effective not only for losing weight but also for lowering abnormal blood sugar levels and other lifestyle diseases.

At the end of this article, I'd like to weigh in on this. To get straight to the point, the right way of losing weight, my thinking is closer to that of a Locabo and a Sugar Busters diet, but I’m wondering if the hormone insulin is the key to these diets.

Locabo is not strict but rather a loose carbohydrate restriction.
By definition, the diet tries to keep the carbohydrate intake amount per day to around seventy to one hundred and thirty grams in total, by taking twenty to forty grams per meal, three times a day and also a dessert or sweets up to ten grams. 

The difference from a strict carbohydrate restriction is that by eating at least seventy grams of carbohydrates, it avoids an extremely low-carbohydrate condition that results in “Ketosis.”

<Old history of low carbohydrate diets>

In Japan, when the Locabo diet first garnered attention around 2015, people thought it was a new dieting method. However, it seems to be a way that has been repeatedly conducted around the world since the 1800’s. I’ll explain this in the link below.

 Do Carbohydrates Make Us Fat or Do Too Many Calories?: The debate since the 1800's
    

I’d like to introduce “Sugar Busters,” which was a trend since the late 1990’s, especially in the U.S. (New Orleans) and was called the “food revolution.” 

Those who advocated the Sugar Busters diet said that the point of Sugar Busters was to regulate the secretion of insulin. They also said that insulin control depends on restricting carbohydrate intake. 

The way of losing weight on these low-carb diets is close to my idea, but from the perspective of my theory, the implications are a little different. Allow me to explain.

I feel that carbohydrates are treated as culprits that make people fat in this diet method because they stimulate insulin secretion. I agree that abnormal blood glucose levels are associated with various diseases and that carbohydrates are a major contributing factor that make people fat.

However, I would like to believe that insulin secretion, even though it promotes fat storage, does not create the fundamental difference between people who are obese, and lean people.

As I have mentioned many times in this blog, the root cause of being overweight, in my opinion, is an “increased base weight,” which is caused by intestinal starvation. And this is more likely to occur with digestible carbohydrates and protein, even in small amounts, combined with an unbalanced diet.

On the other hand, if you want to lose weight, I believe, as Locabo and Sugar Busters do, that reducing the percentage of carbohydrates in the diet and conversely increasing meat, fat, vegetables, and dairy products, etc. is effective.

In this case, the direct implication of reducing carbohydrates is to cut back on glucose that provides immediate energy. So, the body must obtain energy from protein (amino acids) and fat. It is also said to be useful in improving lifestyle-related diseases because it suppresses the rise in blood glucose levels.

In other words, I believe that carbohydrates are not the culprit that directly make people fat. It is more important to eat in balance with relatively more meat, vegetables, cheese, and fat, etc., and to feel less hunger. 

Some people who advocate a low-carb diet say, "As long as you adjust your insulin secretion, you can eat anything without worrying about calories, even fatty foods, cheese, and meat. And since that's how you lost weight, it was the carbohydrates, not the caloric intake, that was the reason." 
I don’t think this explanation is correct.

References：
[1]Satoshi Yamada, The Truth of Carbohydrate Restriction, (山田悟, 「糖質制限の真実」）2015, Pages 114-7.
[2]H. Leigton Steward, Morrison Bethea, Sam S. Andrews, and Luis Balart, Sugar Busters, 1998.

(1) Since around 2015, the low-carb diet has become a trend in Japan, not a fad diet. This is due to the fact that many people prefer diets high in carbohydrates (rice, bread, noodles, etc.) and along with that, obesity and diabetes are on the rise. (In fact, many still believe in the "calorie principle," so they are cutting back not only on carbohydrates, but also on calories.)

(2) In the U. S. (New Orleans), the Sugar Busters was a trend in the late 1900’s. This was more than fifteen years before a low-carb diet became a trend in Japan.

(3) Doctors and others who advocate low-carb diets say that regulating insulin secretion is the key to this diet, but I beg to differ. I believe it is worthwhile to reduce carbohydrate intake while increasing the intake amount of meats, fat, vegetables, and dairy products, etc. This allows undigested food to remain in the intestines for a longer period of time, resulting in less hunger, which in turn reduces absorption ability.

I would like to share with you an interesting story based on profound research that is also relevant to my theory. I will conclude this post with my thoughts.

 【Related article】The Combination of Thin and Overweight in the Same Poor Group Is Not Contradictory

<In 2003>

"Improved prosperity" caused the epidemic, aided and abetted by the food and entertainment industries, as the New York University nutritionist Marion Nestle explained in the journal Science in 2003. “They turn people with expendable income into consumers of aggressively marketed foods that are high in energy but low in nutritional value, and of cars, television sets, and computers that promote sedentary behavior. Gaining weight is good for business.”

The Yale University psychologist Kelly Brownell coined the term "toxic environment" to describe the same notion. 

▽The World Health Organization (WHO) uses the identical logic to explain the obesity epidemic worldwide, blaming it on rising incomes, urbanization, "shifts toward less physically demanding work...moves toward less physical activity...and more passive leisure pursuits."

Obesity researchers now use a quasi-scientific term to describe exactly this condition: they refer to the “obesigenic" environment in which we now live, meaning an environment that is prone to turning lean people into fat ones.[1]"
    

In Japan as well, this idea is widely accepted, and most experts on television explain that overeating and physical inactivity are the causes of obesity.
  

However, what we have to consider here is that obesity is spreading in the poor layers of society, too.
 

"One piece of evidence that needs to be considered in this context, however, is the well-documented fact that being fat is associated with poverty, not prosperity－certainly in women, and often in men. The poorer we are, the fatter we're likely to be. (*snip*)

Between 1901 and 1905, two anthropologists independently studied the Pima (Native American tribe in Arizona), and both commented on how fat they were, particularly the women.
Through the 1850s, the Pima had been extraordinarily successful hunters and farmers. By the 1870s, the Pima, however, were living through what they called the “years of famine.” (*snip*)

(A quarter-century after Russell and Hrdlička visited Pima)

Two researchers from the University of Chicago studied another 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. Many had no plumbing and no running water. Forty percent of the children lived in homes without any kind of toilets. 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.”[3]
     

<About the case of Manhattanites, in the early 1960's>

"This was first reported in a survey of New Yorkers－midtown Manhattanites－in the early 1960s: obese women were six times more likely to be poor than rich; obese men, twice as likely. (*snip*)

Can it be possible that the obesity epidemic is caused by prosperity, so the richer we get, the fatter we get, and that obesity associates with poverty, so the poorer we are, the more likely we are to be fat?

It's not impossible. Maybe poor people don't have the peer pressure that rich people do to remain thin. Believe it or not, this has been one of the accepted explanations for this apparent paradox.

Another commonly accepted explanation for the association between obesity and poverty is that fatter women marry down in social class and so collect at the bottom rungs of the ladder; thinner women marry up.
  

<About the case of the Pima (Native American tribe in Arizona >

So why were they fat? Years of starvation are supposed to take weight off, not put it on or leave it on, as the case may be. And if the government rations were simply excessive, making the famines a thing of the past, then why would the Pima get fat on the abundant rations and not on the abundant food they'd had prior to the famines?

Hrdlička also thought that their physical inactivity was the cause of obesity because they were sedentary in comparison with what they used to be. This is what Hrdlička called “the change from their past active life to the present state of not a little indolence.” But then he couldn't explain why the women were typically the fat ones, even though the women did virtually all the hard labor in the villages—harvesting the crops, grinding the grain, even carrying the heavy burdens.

The Pima were already eating everything “that enters into the dietary of the white man,” as Hrdlička said. This might have been key. The Pima diet in 1900 had characteristics very similar to the diets many of us are eating a century later, but not in quantity, in quality.[5]"
    

I want to explain my consideration based on numbers one to three.
First of all, when considering "obesity," isn't it too simplistic to think that obesity has increased since we have become wealthier? 

That is to say, even if someone is said to be wealthy, with regards to food, there are many things in common with groups that live in poverty with a high rate of obesity. As Mr. Taubes says, what is important now is the “quality” of food rather than the “quantity.”

References：
[1](Gary Taubes, Why We Get Fat, 2010, Pages 17-18)
[2] P. 18, 29
[3] P. 20-24
[4] P. 18-19
[5] P. 22-23
[6] P.134, 150