The full text of this article is 10,000 words. Please read
patiently to know why we are fat, so that we can figure out how we can not be fat.
There is another important benefit. Many popular weight loss methods propose a set of weight loss theories, which are all aimed at the "root cause of obesity" they are doing. Knowing the real reason for getting fat, it is not so easy to fool these weight loss methods.
I have been emphasizing the complexity of the human body on various occasions. It is not an exaggeration to understand how complex the human body is. 80% of the pseudoscience on the market are no longer effective in your own right. You will be defeated without any attack.
Pseudoscience is accustomed to saying the human body very simply, both black and white, simple and crude.
Just do these actions for a few months and you will become a muscular man. Just eat one thing to cure all kinds of diseases, and you can live longer if you drink water. In fact, is the world really so simple and beautiful? That's fine. If you know the complexity of the human body, these things will not deceive you.
is really a carbohydrate that makes humans fat?
Similarly, people will get fat, and the reasons are very complicated, and they are definitely not caused by one factor. In 1727, there was a book called "On the Causes and Impacts of Obesity", which was the first book in human history to study obesity.
From 1727 to the present, humans have studied obesity for 289 years. What's the result? There are more and more fat people. If fat is really that simple, it is because you eat too much of a certain type of thing, then you don’t have to work so hard to lose weight.
Not to mention the common people, many international supermodels, international celebrities, and political people, they are all hungry, exercise desperately, and even induce vomiting after meals, or use weight loss pills with high side effects and have liposuction surgery to lose weight.
If obesity is really caused by a simple factor, are you still using this?
Some people say that most people are fat, nothing else, they eat too much carbohydrates and have high insulin. Even if you eat a lot of calories, you can lose weight as long as you eat less carbohydrates. Even if you eat very little calories, you will not lose weight as long as you eat a little more carbohydrates.
"Carbohydrates are the fundamental cause of obesity" is a theoretical foundation for many low-carbon weight loss methods. Of course, many times they use delicate sugars to operate, but in fact they are forbidden to eat more carbohydrates.
Today I will help you understand what causes obesity, and whether it is like some people say that you eat too much carbohydrate. They said that Americans have eaten too much carbohydrates and less fat for a while. Look, aren’t they getting fat? Their data itself has problems, which we will talk about in this article.
In addition, they did not consider the changes in American activity and the changes in Americans' overall calorie intake. Just talking about carbohydrates and fats is a hooliganism.
There are many factors that affect fatness and thinness. The population of underdeveloped countries eats more carbohydrates than those of developed countries. They are poor and can only afford plant-based foods. But we all know that there are more fat people in developed countries.
talks with data. According to FAO/WHO statistics, most developed countries have relatively low carbohydrate energy supply, about 40%, and eat very little. In underdeveloped countries, 80%, and the proportion of starchy food is very large [1] (everyone now knows that vegetables and fruits are expensive, but starchy foods are still cheap).
Take our own data as an example. The Institute of Nutrition and Food Safety of the Chinese Center for Disease Control and Prevention, and the Population Center of the University of North Carolina, conducted a total of 8 Chinese health and nutrition surveys from 1989 to 2009.
In the past 20 years, Chinese people generally have eaten less carbohydrates in and have significantly more fat (mainly animal fat). At the same time, the total energy intake is less than . In other words, in the past 20 years, we have eaten a lot of animal foods, especially livestock meat and egg foods, while the consumption of cereal rhizome foods has dropped significantly [2-6].
Isn’t this the weight loss diet structure that some people have been promoting? But have Chinese people lost weight in the past 20 years?
According to the "Current Status of Nutrition and Health of Chinese Residents" released by the Ministry of Health, Ministry of Science and Technology, and National Bureau of Statistics in October 2004, compared with 1992, China's overweight population increased by 38.6%, and the obesity rate increased by 80.6%! Not only are Chinese people not thin, they are also fat. Eating according to their diet is not only not thin, but Chinese people are also fat.
Although this does not mean that fat makes Chinese people fat (because there are also factors that reduce activity).
But at least it can be explained that it is impossible to make a group of people fat just by carbohydrates. Fatness is the result of the combined effect of multiple factors. They brag too much. But some people may think, since you said what they were wrong, it was not that carbohydrates made us fat, how can we limit carbohydrates and lose weight?
Thinking about this is actually a logical mistake. Not eating carbohydrates can make people lose weight, but it does not mean that carbohydrates can make people gain weight. It’s like taking drugs can make people lose weight, but it cannot be said that people are fat because they don’t take drugs.
Why do we become fat?
obesity is currently divided into two types, one is called "lifestyle-related obesity", or primary obesity. This type of obesity accounts for about 95% of all obesity. Another type is pathological obesity, because there is a certain disease or the use of certain drugs that cause obesity. This obesity is a very small number, and it is not possible to solve the problem simply by losing weight, so we will not discuss it. Why is
primary obesity?
Why do we suddenly gain weight within decades? There is a view that global obesity problems are caused by genes. However, we look at the history of human obesity: Demographic research says that the obesity problem in modern society emerged in Western society at the beginning of the last century. However, in the 1940s, World War II was in chaos, and the problem of obesity temporarily disappeared during this period. After the war, during the continuous peace period, obesity began to occur again in Europe, Asia and North America. At the end of the last century, obesity problems also occurred in South America and Africa.
That is to say, obesity spreads through just two generations. This shows that the epidemic of this obesity is not caused by genes, but mainly influenced by environmental factors. Because the genes are not changed so quickly. But we have discovered another thing: in the same environment, there are fat people and thin people.
Eat similar things and move similar activities. Some people are fat and some people are thin. This also shows that fatness and thinness are still related to genes.
Therefore, it is generally believed that from the perspective of the crowd, a group of people gets fat, which is mainly caused by environmental changes. For example, Chinese people are now becoming more and more obesity, which is mainly caused by environmental changes and is related to their lifestyle. This lifestyle, which includes a lot of complex factors, is ultimately attributed to energy imbalances - excessive energy intake and excessive energy consumption.
But for everyone, fatness and weight are more determined by genes. In other words, the weight of Chinese people is mainly caused by environmental changes. But among the Chinese, Zhang San is fat and Li Si is not fat, which is mainly determined by genes. The weight of an individual is mainly determined by genes, and this view is basically clear now. There is a lot of evidence in this regard, such as twin studies, which can explain the problem. The genes of identical twins are similar, and studies have found that their BMI similarity is also very high. Even if twins who do not live in the same environment, such as adopting one, although the living environments of the two twins are different, the BMIs of the two brothers or sisters are still surprisingly similar.
The above chart [8] is the similarity between people with different relationships. We can see that the spouse has the lowest similarity of fat and thinness. The couple's lifestyle is very similar, but the BMI is not very similar. Because the genes are far away. The BMI similarity between parents and children is higher because of blood relationship.
The similarity between brothers and sisters is higher because the genetic similarity between them is also higher.
The full text of this article is 10,000 words. Please read
patiently to know why we are fat, so that we can figure out how we can not be fat.
There is another important benefit. Many popular weight loss methods propose a set of weight loss theories, which are all aimed at the "root cause of obesity" they are doing. Knowing the real reason for getting fat, it is not so easy to fool these weight loss methods.
I have been emphasizing the complexity of the human body on various occasions. It is not an exaggeration to understand how complex the human body is. 80% of the pseudoscience on the market are no longer effective in your own right. You will be defeated without any attack.
Pseudoscience is accustomed to saying the human body very simply, both black and white, simple and crude.
Just do these actions for a few months and you will become a muscular man. Just eat one thing to cure all kinds of diseases, and you can live longer if you drink water. In fact, is the world really so simple and beautiful? That's fine. If you know the complexity of the human body, these things will not deceive you.
is really a carbohydrate that makes humans fat?
Similarly, people will get fat, and the reasons are very complicated, and they are definitely not caused by one factor. In 1727, there was a book called "On the Causes and Impacts of Obesity", which was the first book in human history to study obesity.
From 1727 to the present, humans have studied obesity for 289 years. What's the result? There are more and more fat people. If fat is really that simple, it is because you eat too much of a certain type of thing, then you don’t have to work so hard to lose weight.
Not to mention the common people, many international supermodels, international celebrities, and political people, they are all hungry, exercise desperately, and even induce vomiting after meals, or use weight loss pills with high side effects and have liposuction surgery to lose weight.
If obesity is really caused by a simple factor, are you still using this?
Some people say that most people are fat, nothing else, they eat too much carbohydrates and have high insulin. Even if you eat a lot of calories, you can lose weight as long as you eat less carbohydrates. Even if you eat very little calories, you will not lose weight as long as you eat a little more carbohydrates.
"Carbohydrates are the fundamental cause of obesity" is a theoretical foundation for many low-carbon weight loss methods. Of course, many times they use delicate sugars to operate, but in fact they are forbidden to eat more carbohydrates.
Today I will help you understand what causes obesity, and whether it is like some people say that you eat too much carbohydrate. They said that Americans have eaten too much carbohydrates and less fat for a while. Look, aren’t they getting fat? Their data itself has problems, which we will talk about in this article.
In addition, they did not consider the changes in American activity and the changes in Americans' overall calorie intake. Just talking about carbohydrates and fats is a hooliganism.
There are many factors that affect fatness and thinness. The population of underdeveloped countries eats more carbohydrates than those of developed countries. They are poor and can only afford plant-based foods. But we all know that there are more fat people in developed countries.
talks with data. According to FAO/WHO statistics, most developed countries have relatively low carbohydrate energy supply, about 40%, and eat very little. In underdeveloped countries, 80%, and the proportion of starchy food is very large [1] (everyone now knows that vegetables and fruits are expensive, but starchy foods are still cheap).
Take our own data as an example. The Institute of Nutrition and Food Safety of the Chinese Center for Disease Control and Prevention, and the Population Center of the University of North Carolina, conducted a total of 8 Chinese health and nutrition surveys from 1989 to 2009.
In the past 20 years, Chinese people generally have eaten less carbohydrates in and have significantly more fat (mainly animal fat). At the same time, the total energy intake is less than . In other words, in the past 20 years, we have eaten a lot of animal foods, especially livestock meat and egg foods, while the consumption of cereal rhizome foods has dropped significantly [2-6].
Isn’t this the weight loss diet structure that some people have been promoting? But have Chinese people lost weight in the past 20 years?
According to the "Current Status of Nutrition and Health of Chinese Residents" released by the Ministry of Health, Ministry of Science and Technology, and National Bureau of Statistics in October 2004, compared with 1992, China's overweight population increased by 38.6%, and the obesity rate increased by 80.6%! Not only are Chinese people not thin, they are also fat. Eating according to their diet is not only not thin, but Chinese people are also fat.
Although this does not mean that fat makes Chinese people fat (because there are also factors that reduce activity).
But at least it can be explained that it is impossible to make a group of people fat just by carbohydrates. Fatness is the result of the combined effect of multiple factors. They brag too much. But some people may think, since you said what they were wrong, it was not that carbohydrates made us fat, how can we limit carbohydrates and lose weight?
Thinking about this is actually a logical mistake. Not eating carbohydrates can make people lose weight, but it does not mean that carbohydrates can make people gain weight. It’s like taking drugs can make people lose weight, but it cannot be said that people are fat because they don’t take drugs.
Why do we become fat?
obesity is currently divided into two types, one is called "lifestyle-related obesity", or primary obesity. This type of obesity accounts for about 95% of all obesity. Another type is pathological obesity, because there is a certain disease or the use of certain drugs that cause obesity. This obesity is a very small number, and it is not possible to solve the problem simply by losing weight, so we will not discuss it. Why is
primary obesity?
Why do we suddenly gain weight within decades? There is a view that global obesity problems are caused by genes. However, we look at the history of human obesity: Demographic research says that the obesity problem in modern society emerged in Western society at the beginning of the last century. However, in the 1940s, World War II was in chaos, and the problem of obesity temporarily disappeared during this period. After the war, during the continuous peace period, obesity began to occur again in Europe, Asia and North America. At the end of the last century, obesity problems also occurred in South America and Africa.
That is to say, obesity spreads through just two generations. This shows that the epidemic of this obesity is not caused by genes, but mainly influenced by environmental factors. Because the genes are not changed so quickly. But we have discovered another thing: in the same environment, there are fat people and thin people.
Eat similar things and move similar activities. Some people are fat and some people are thin. This also shows that fatness and thinness are still related to genes.
Therefore, it is generally believed that from the perspective of the crowd, a group of people gets fat, which is mainly caused by environmental changes. For example, Chinese people are now becoming more and more obesity, which is mainly caused by environmental changes and is related to their lifestyle. This lifestyle, which includes a lot of complex factors, is ultimately attributed to energy imbalances - excessive energy intake and excessive energy consumption.
But for everyone, fatness and weight are more determined by genes. In other words, the weight of Chinese people is mainly caused by environmental changes. But among the Chinese, Zhang San is fat and Li Si is not fat, which is mainly determined by genes. The weight of an individual is mainly determined by genes, and this view is basically clear now. There is a lot of evidence in this regard, such as twin studies, which can explain the problem. The genes of identical twins are similar, and studies have found that their BMI similarity is also very high. Even if twins who do not live in the same environment, such as adopting one, although the living environments of the two twins are different, the BMIs of the two brothers or sisters are still surprisingly similar.
The above chart [8] is the similarity between people with different relationships. We can see that the spouse has the lowest similarity of fat and thinness. The couple's lifestyle is very similar, but the BMI is not very similar. Because the genes are far away. The BMI similarity between parents and children is higher because of blood relationship.
The similarity between brothers and sisters is higher because the genetic similarity between them is also higher.The similarity of fraternal twins (Dz) is higher, but the similarity of identical twins (Mz) with the highest BMI similarity can reach 70%-95%. In other words, for everyone, fatness and thinness are largely born. Some people may ask, why are you still losing weight?
In fact, there is really a debate in the academic community about whether weight loss is useful. Most of the success we see in weight loss are changes in body shape for each person at a time period. It is actually very difficult to completely turn a fat man into a thin man forever and fight against genes.
Many obesity medical studies have found that most obese people cannot maintain a low weight for a long time through diet control and physical exercise (study also believes that it is relatively easy for people who lose weight independently to do this, so we must also be confident, but this is off-topic) [7] . How does the
gene determine our fatness and thinness?
Generally speaking, there are two situations. One is a single gene factor, that is, a problem with a certain gene has a huge impact and makes people fat.
such as Prader-Willi syndrome. This single gene mutation leads to short stature, hypogonadism, mental retardation, and obesity. However, obesity caused by this single gene mutation is generally pathological obesity and is considered a disease, so we will not discuss it here.
The factors that we discuss about physiological obesity and genes are generally not one, but multiple, which are the result of the joint action of multiple genes.
Each gene plays a little role, and many genes work together, resulting in susceptibility or non-susceptibility to obesity. For example, data previously stated that 253 loci in the human genome may be related to susceptibility to obesity, and each loci includes multiple (or even hundreds) genes.
Let’s give an example. There is an enzyme in the human body called fatty acid amine hydrolase. The role of this enzyme is to degrade endocannabinoids. Endocannabinoids have an appetizing effect and will make people feel more appetizing and eat more. If something like
cannot be degraded well, it will cause people to have hyper appetite and easily lead to obesity. Therefore, some people with genotypes are naturally low in fatty acid amine hydrolase activity, which makes them prone to appetite and gain weight. It has been clarified that there are many genotypes like this that can affect people's fatness and thinness.
For example, in addition to many ways, genes determine people's appetite, but also determine people's choice of food, whether they like high-energy foods, low-energy foods, whether they like meat, or vegetarian foods.
gene also determines how restrained a person is tolerate the temptation of high-energy foods and whether he can tolerate the temptation of high-energy foods; genes also determine how many meals we eat a day; even genes affect the number of people who eat together when a person eats. These factors will affect a person's weight loss.
At the same time, genes also determine our energy consumption. For example, whether there are more or less skeletal muscles in a human, or whether the internal organs are large or small, can affect the basal metabolic rate.
activity heat consumption and food heat consumption are also related to genes. Do we like movement or quiet, love outdoor activities or stay at home, what career we choose, etc., are largely determined by genes and are also related to fatness and thinness.
Even if people like to stand in any posture, they are affected by genes and can also affect energy consumption. Therefore, genes have almost shaped a person's entire life, naturally including fat and thinness.
Why do humans have genes that are prone to fat?
In the past, we always said the "thrift gene", which means that in the process of human evolution, those who are good at storing fat survived, and this gene continued. Now that food is sufficient, people tend to overstoring fat. But this theory is now very controversial. There is now a new theory called the "predation release" hypothesis.
means that during the evolution process, people who are too bad at storing energy cannot survive. It’s not okay to be too good at storing energy, because you are too fat and you are easily caught up by predators.
So, 2 million to 6 million years ago, a person's weight might have a lower limit and an upper limit. It is certainly not good to be too thin, but those who are too fat will be eliminated.
But as fire, weapons and buildings become stronger and stronger, people gradually do not have to avoid predators, and human weight is gradually no upper limit. There is also a mathematical model for this hypothesis, which is said to be quite accurate in predicting the BMI distribution of modern people. Of course, genes largely determine individual fatness and thinness, but it does not mean that our fatness and thinness are not affected by our lifestyle.
can only be said that for everyone, fatness and thinness are mainly affected by gene regulation and environment, and are also an aspect, but only a relatively minor aspect. But no matter what, being fat is also the result of the combined effect of genes and environment. Just how much food is eaten is just a small part of the many factors that determine a person's weight and weight. It is far from enough to determine a person's weight and weight. What impact does the
environment have on our fat and thinness?
The right genes may become fat when encountering the right environment. Genetic factors are complex, and environmental factors are the same. But it mainly revolves around the two aspects of reducing calorie consumption and increasing calorie intake. In terms of reducing calorie consumption, more vehicles and labor-saving tools and changing their working methods will reduce people's calorie consumption.
and even the heating cost is reduced. People often stay in a warm environment, which will also reduce people's calorie consumption (people consume more calorie in cold environments). Watching TV and sitting for a long time and moving less can also significantly reduce calorie consumption.
Moreover, sitting on the sofa watching TV will not only reduce people's calorie consumption, but also may increase calorie intake. Because many people eat snacks while watching TV. Some studies estimate that people increase their caloric intake by more than 160 kcal per hour when watching TV [24]. Watching TV can even disrupt the signal of satiety inside the human body, allowing us to keep eating [28, 35].
In terms of changes in dietary structure, such as the increase in animal foods with high fat and low fiber, it will lead to factors such as increasing food intake, which will lead to a tendency to become fat. Research on in this regard is rich in evidence [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23].
They say that fat will not make people fat, and these evidences themselves are enough to refute his statement. Increased portion size in a single meal and eating large portions of food are also a factor that leads to an increase in dietary calorie intake (more than 50% of normal intake) [25]. Moreover, there are studies that the amount of food eaten has a clear relationship with BMI. The larger the food, the greater the BMI [29, 30].
There is a very interesting experiment here called the "bottomless soup bowl" experiment.
Researchers designed a special bowl. We ordinary people say that it is a mechanism. When there is still 1/4 of the soup in the bowl, it will be refilled automatically, but those who drink the soup will not realize it. In other words, the subjects of the experiment thought that there was only one bowl of soup, but in fact, this bowl of soup would never be finished.
So, when the subjects were drinking soup, they unknowingly drank 73% more than usual (113 kcal), but they did not feel that they drank more than usual, nor did they feel that they could last [37].
This means that when people decide how much they should eat, they often rely on a visual hint to judge, that is, to see how much is left in the bowl. Therefore, eating large portions of food will make people involuntarily eat more (the single portion of fast food is getting bigger and bigger).
Dietary diversification will also lead to an increase in calories intake [26].
There are experiments that feed animals with different flavors of feed, and the experimental animals will consume 25% more energy and increase their weight [31]. People who eat different foods within a few days or months consume more energy than those who eat a single food [32, 33].
Actually, this is not surprising. In layman's terms, eating the same kinds of things every day will make you tired of it after eating for a few days and you will be full as soon as you eat it. In academic language, this is called " sensory specific satiety ".
Sensory specific satiety means that when you eat something, people's pleasure in the taste of this food and sensory attention will be reduced and they will not like it so much. And you have a high sense of taste and a high degree of attention for things you have never eaten.
Therefore, if you often eat a few limited foods, these things will taste less, and people's interest in these foods will also decrease, making people eat less. Their low-carbon diet is also a restricted diet type.
Those who have really read their books will know that they have very strict restrictions on food types, and they cannot eat them, and there are only a few that can be eaten. This will make people eat less invisibly. The increase in the number of meals outside is also a reason for increasing calorie intake, and it is related to obesity [34].
has data reports. From 1977 to 1978, eating out caused a daily calorie intake to increase by nearly 300 kcal/day [27]. Although this is an old data, it can reflect basic rules.
or even, the increase in the number of people who eat together will also lead to an increase in calories, and a maximum meal can increase by 400 kcal [36]. That is to say, the more people you eat, the more you are likely to eat.
This is called " energy intake population promotion phenomenon ". This is also a proven factor that causes obesity in modern people. In addition, eating snacks, not eating breakfast, stressful eating caused by stressful life rhythm, etc. are all possible reasons for environmental factors that cause increased calories intake and thus obesity. There are many factors in this regard and countless research studies, so I will not give examples one by one.
We can use the following chart to summarize the impact of the environment (which also includes some genetic control factors) on energy balance. We can see that the relationship is very complicated. This model is just a simple summary focusing on the aspect of environmental factors.
If you fight against genes and environment, you won’t make yourself fat so easily
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My next article has also been updated. Everyone is welcome to see how carbohydrates are not easy to make people fat. What is the truth about high insulin?
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［36］：de Castro JM. and Brewer EM. The amount eaten in meals by humans is a power function of the number of people present. Physical Behav. 1992, 51:121-25.
［37］：Wansink B, Painter JE, North J. Bottomless bowls: why visual cues of portion size may influence intake. Ones Res. 2005, 13:93-100.
But as fire, weapons and buildings become stronger and stronger, people gradually do not have to avoid predators, and human weight is gradually no upper limit. There is also a mathematical model for this hypothesis, which is said to be quite accurate in predicting the BMI distribution of modern people. Of course, genes largely determine individual fatness and thinness, but it does not mean that our fatness and thinness are not affected by our lifestyle.
can only be said that for everyone, fatness and thinness are mainly affected by gene regulation and environment, and are also an aspect, but only a relatively minor aspect. But no matter what, being fat is also the result of the combined effect of genes and environment. Just how much food is eaten is just a small part of the many factors that determine a person's weight and weight. It is far from enough to determine a person's weight and weight. What impact does the
environment have on our fat and thinness?
The right genes may become fat when encountering the right environment. Genetic factors are complex, and environmental factors are the same. But it mainly revolves around the two aspects of reducing calorie consumption and increasing calorie intake. In terms of reducing calorie consumption, more vehicles and labor-saving tools and changing their working methods will reduce people's calorie consumption.
and even the heating cost is reduced. People often stay in a warm environment, which will also reduce people's calorie consumption (people consume more calorie in cold environments). Watching TV and sitting for a long time and moving less can also significantly reduce calorie consumption.
Moreover, sitting on the sofa watching TV will not only reduce people's calorie consumption, but also may increase calorie intake. Because many people eat snacks while watching TV. Some studies estimate that people increase their caloric intake by more than 160 kcal per hour when watching TV [24]. Watching TV can even disrupt the signal of satiety inside the human body, allowing us to keep eating [28, 35].
In terms of changes in dietary structure, such as the increase in animal foods with high fat and low fiber, it will lead to factors such as increasing food intake, which will lead to a tendency to become fat. Research on in this regard is rich in evidence [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23].
They say that fat will not make people fat, and these evidences themselves are enough to refute his statement. Increased portion size in a single meal and eating large portions of food are also a factor that leads to an increase in dietary calorie intake (more than 50% of normal intake) [25]. Moreover, there are studies that the amount of food eaten has a clear relationship with BMI. The larger the food, the greater the BMI [29, 30].
There is a very interesting experiment here called the "bottomless soup bowl" experiment.
Researchers designed a special bowl. We ordinary people say that it is a mechanism. When there is still 1/4 of the soup in the bowl, it will be refilled automatically, but those who drink the soup will not realize it. In other words, the subjects of the experiment thought that there was only one bowl of soup, but in fact, this bowl of soup would never be finished.
So, when the subjects were drinking soup, they unknowingly drank 73% more than usual (113 kcal), but they did not feel that they drank more than usual, nor did they feel that they could last [37].
This means that when people decide how much they should eat, they often rely on a visual hint to judge, that is, to see how much is left in the bowl. Therefore, eating large portions of food will make people involuntarily eat more (the single portion of fast food is getting bigger and bigger).
Dietary diversification will also lead to an increase in calories intake [26].
There are experiments that feed animals with different flavors of feed, and the experimental animals will consume 25% more energy and increase their weight [31]. People who eat different foods within a few days or months consume more energy than those who eat a single food [32, 33].
Actually, this is not surprising. In layman's terms, eating the same kinds of things every day will make you tired of it after eating for a few days and you will be full as soon as you eat it. In academic language, this is called " sensory specific satiety ".
Sensory specific satiety means that when you eat something, people's pleasure in the taste of this food and sensory attention will be reduced and they will not like it so much. And you have a high sense of taste and a high degree of attention for things you have never eaten.
Therefore, if you often eat a few limited foods, these things will taste less, and people's interest in these foods will also decrease, making people eat less. Their low-carbon diet is also a restricted diet type.
Those who have really read their books will know that they have very strict restrictions on food types, and they cannot eat them, and there are only a few that can be eaten. This will make people eat less invisibly. The increase in the number of meals outside is also a reason for increasing calorie intake, and it is related to obesity [34].
has data reports. From 1977 to 1978, eating out caused a daily calorie intake to increase by nearly 300 kcal/day [27]. Although this is an old data, it can reflect basic rules.
or even, the increase in the number of people who eat together will also lead to an increase in calories, and a maximum meal can increase by 400 kcal [36]. That is to say, the more people you eat, the more you are likely to eat.
This is called " energy intake population promotion phenomenon ". This is also a proven factor that causes obesity in modern people. In addition, eating snacks, not eating breakfast, stressful eating caused by stressful life rhythm, etc. are all possible reasons for environmental factors that cause increased calories intake and thus obesity. There are many factors in this regard and countless research studies, so I will not give examples one by one.
We can use the following chart to summarize the impact of the environment (which also includes some genetic control factors) on energy balance. We can see that the relationship is very complicated. This model is just a simple summary focusing on the aspect of environmental factors.
The full text of this article is 10,000 words. Please read
patiently to know why we are fat, so that we can figure out how we can not be fat.
There is another important benefit. Many popular weight loss methods propose a set of weight loss theories, which are all aimed at the "root cause of obesity" they are doing. Knowing the real reason for getting fat, it is not so easy to fool these weight loss methods.
I have been emphasizing the complexity of the human body on various occasions. It is not an exaggeration to understand how complex the human body is. 80% of the pseudoscience on the market are no longer effective in your own right. You will be defeated without any attack.
Pseudoscience is accustomed to saying the human body very simply, both black and white, simple and crude.
Just do these actions for a few months and you will become a muscular man. Just eat one thing to cure all kinds of diseases, and you can live longer if you drink water. In fact, is the world really so simple and beautiful? That's fine. If you know the complexity of the human body, these things will not deceive you.
is really a carbohydrate that makes humans fat?
Similarly, people will get fat, and the reasons are very complicated, and they are definitely not caused by one factor. In 1727, there was a book called "On the Causes and Impacts of Obesity", which was the first book in human history to study obesity.
From 1727 to the present, humans have studied obesity for 289 years. What's the result? There are more and more fat people. If fat is really that simple, it is because you eat too much of a certain type of thing, then you don’t have to work so hard to lose weight.
Not to mention the common people, many international supermodels, international celebrities, and political people, they are all hungry, exercise desperately, and even induce vomiting after meals, or use weight loss pills with high side effects and have liposuction surgery to lose weight.
If obesity is really caused by a simple factor, are you still using this?
Some people say that most people are fat, nothing else, they eat too much carbohydrates and have high insulin. Even if you eat a lot of calories, you can lose weight as long as you eat less carbohydrates. Even if you eat very little calories, you will not lose weight as long as you eat a little more carbohydrates.
"Carbohydrates are the fundamental cause of obesity" is a theoretical foundation for many low-carbon weight loss methods. Of course, many times they use delicate sugars to operate, but in fact they are forbidden to eat more carbohydrates.
Today I will help you understand what causes obesity, and whether it is like some people say that you eat too much carbohydrate. They said that Americans have eaten too much carbohydrates and less fat for a while. Look, aren’t they getting fat? Their data itself has problems, which we will talk about in this article.
In addition, they did not consider the changes in American activity and the changes in Americans' overall calorie intake. Just talking about carbohydrates and fats is a hooliganism.
There are many factors that affect fatness and thinness. The population of underdeveloped countries eats more carbohydrates than those of developed countries. They are poor and can only afford plant-based foods. But we all know that there are more fat people in developed countries.
talks with data. According to FAO/WHO statistics, most developed countries have relatively low carbohydrate energy supply, about 40%, and eat very little. In underdeveloped countries, 80%, and the proportion of starchy food is very large [1] (everyone now knows that vegetables and fruits are expensive, but starchy foods are still cheap).
Take our own data as an example. The Institute of Nutrition and Food Safety of the Chinese Center for Disease Control and Prevention, and the Population Center of the University of North Carolina, conducted a total of 8 Chinese health and nutrition surveys from 1989 to 2009.
In the past 20 years, Chinese people generally have eaten less carbohydrates in and have significantly more fat (mainly animal fat). At the same time, the total energy intake is less than . In other words, in the past 20 years, we have eaten a lot of animal foods, especially livestock meat and egg foods, while the consumption of cereal rhizome foods has dropped significantly [2-6].
Isn’t this the weight loss diet structure that some people have been promoting? But have Chinese people lost weight in the past 20 years?
According to the "Current Status of Nutrition and Health of Chinese Residents" released by the Ministry of Health, Ministry of Science and Technology, and National Bureau of Statistics in October 2004, compared with 1992, China's overweight population increased by 38.6%, and the obesity rate increased by 80.6%! Not only are Chinese people not thin, they are also fat. Eating according to their diet is not only not thin, but Chinese people are also fat.
Although this does not mean that fat makes Chinese people fat (because there are also factors that reduce activity).
But at least it can be explained that it is impossible to make a group of people fat just by carbohydrates. Fatness is the result of the combined effect of multiple factors. They brag too much. But some people may think, since you said what they were wrong, it was not that carbohydrates made us fat, how can we limit carbohydrates and lose weight?
Thinking about this is actually a logical mistake. Not eating carbohydrates can make people lose weight, but it does not mean that carbohydrates can make people gain weight. It’s like taking drugs can make people lose weight, but it cannot be said that people are fat because they don’t take drugs.
Why do we become fat?
obesity is currently divided into two types, one is called "lifestyle-related obesity", or primary obesity. This type of obesity accounts for about 95% of all obesity. Another type is pathological obesity, because there is a certain disease or the use of certain drugs that cause obesity. This obesity is a very small number, and it is not possible to solve the problem simply by losing weight, so we will not discuss it. Why is
primary obesity?
Why do we suddenly gain weight within decades? There is a view that global obesity problems are caused by genes. However, we look at the history of human obesity: Demographic research says that the obesity problem in modern society emerged in Western society at the beginning of the last century. However, in the 1940s, World War II was in chaos, and the problem of obesity temporarily disappeared during this period. After the war, during the continuous peace period, obesity began to occur again in Europe, Asia and North America. At the end of the last century, obesity problems also occurred in South America and Africa.
That is to say, obesity spreads through just two generations. This shows that the epidemic of this obesity is not caused by genes, but mainly influenced by environmental factors. Because the genes are not changed so quickly. But we have discovered another thing: in the same environment, there are fat people and thin people.
Eat similar things and move similar activities. Some people are fat and some people are thin. This also shows that fatness and thinness are still related to genes.
Therefore, it is generally believed that from the perspective of the crowd, a group of people gets fat, which is mainly caused by environmental changes. For example, Chinese people are now becoming more and more obesity, which is mainly caused by environmental changes and is related to their lifestyle. This lifestyle, which includes a lot of complex factors, is ultimately attributed to energy imbalances - excessive energy intake and excessive energy consumption.
But for everyone, fatness and weight are more determined by genes. In other words, the weight of Chinese people is mainly caused by environmental changes. But among the Chinese, Zhang San is fat and Li Si is not fat, which is mainly determined by genes. The weight of an individual is mainly determined by genes, and this view is basically clear now. There is a lot of evidence in this regard, such as twin studies, which can explain the problem. The genes of identical twins are similar, and studies have found that their BMI similarity is also very high. Even if twins who do not live in the same environment, such as adopting one, although the living environments of the two twins are different, the BMIs of the two brothers or sisters are still surprisingly similar.
The above chart [8] is the similarity between people with different relationships. We can see that the spouse has the lowest similarity of fat and thinness. The couple's lifestyle is very similar, but the BMI is not very similar. Because the genes are far away. The BMI similarity between parents and children is higher because of blood relationship.
The similarity between brothers and sisters is higher because the genetic similarity between them is also higher.The similarity of fraternal twins (Dz) is higher, but the similarity of identical twins (Mz) with the highest BMI similarity can reach 70%-95%. In other words, for everyone, fatness and thinness are largely born. Some people may ask, why are you still losing weight?
In fact, there is really a debate in the academic community about whether weight loss is useful. Most of the success we see in weight loss are changes in body shape for each person at a time period. It is actually very difficult to completely turn a fat man into a thin man forever and fight against genes.
Many obesity medical studies have found that most obese people cannot maintain a low weight for a long time through diet control and physical exercise (study also believes that it is relatively easy for people who lose weight independently to do this, so we must also be confident, but this is off-topic) [7] . How does the
gene determine our fatness and thinness?
Generally speaking, there are two situations. One is a single gene factor, that is, a problem with a certain gene has a huge impact and makes people fat.
such as Prader-Willi syndrome. This single gene mutation leads to short stature, hypogonadism, mental retardation, and obesity. However, obesity caused by this single gene mutation is generally pathological obesity and is considered a disease, so we will not discuss it here.
The factors that we discuss about physiological obesity and genes are generally not one, but multiple, which are the result of the joint action of multiple genes.
Each gene plays a little role, and many genes work together, resulting in susceptibility or non-susceptibility to obesity. For example, data previously stated that 253 loci in the human genome may be related to susceptibility to obesity, and each loci includes multiple (or even hundreds) genes.
Let’s give an example. There is an enzyme in the human body called fatty acid amine hydrolase. The role of this enzyme is to degrade endocannabinoids. Endocannabinoids have an appetizing effect and will make people feel more appetizing and eat more. If something like
cannot be degraded well, it will cause people to have hyper appetite and easily lead to obesity. Therefore, some people with genotypes are naturally low in fatty acid amine hydrolase activity, which makes them prone to appetite and gain weight. It has been clarified that there are many genotypes like this that can affect people's fatness and thinness.
For example, in addition to many ways, genes determine people's appetite, but also determine people's choice of food, whether they like high-energy foods, low-energy foods, whether they like meat, or vegetarian foods.
gene also determines how restrained a person is tolerate the temptation of high-energy foods and whether he can tolerate the temptation of high-energy foods; genes also determine how many meals we eat a day; even genes affect the number of people who eat together when a person eats. These factors will affect a person's weight loss.
At the same time, genes also determine our energy consumption. For example, whether there are more or less skeletal muscles in a human, or whether the internal organs are large or small, can affect the basal metabolic rate.
activity heat consumption and food heat consumption are also related to genes. Do we like movement or quiet, love outdoor activities or stay at home, what career we choose, etc., are largely determined by genes and are also related to fatness and thinness.
Even if people like to stand in any posture, they are affected by genes and can also affect energy consumption. Therefore, genes have almost shaped a person's entire life, naturally including fat and thinness.
Why do humans have genes that are prone to fat?
In the past, we always said the "thrift gene", which means that in the process of human evolution, those who are good at storing fat survived, and this gene continued. Now that food is sufficient, people tend to overstoring fat. But this theory is now very controversial. There is now a new theory called the "predation release" hypothesis.
means that during the evolution process, people who are too bad at storing energy cannot survive. It’s not okay to be too good at storing energy, because you are too fat and you are easily caught up by predators.
So, 2 million to 6 million years ago, a person's weight might have a lower limit and an upper limit. It is certainly not good to be too thin, but those who are too fat will be eliminated.
But as fire, weapons and buildings become stronger and stronger, people gradually do not have to avoid predators, and human weight is gradually no upper limit. There is also a mathematical model for this hypothesis, which is said to be quite accurate in predicting the BMI distribution of modern people. Of course, genes largely determine individual fatness and thinness, but it does not mean that our fatness and thinness are not affected by our lifestyle.
can only be said that for everyone, fatness and thinness are mainly affected by gene regulation and environment, and are also an aspect, but only a relatively minor aspect. But no matter what, being fat is also the result of the combined effect of genes and environment. Just how much food is eaten is just a small part of the many factors that determine a person's weight and weight. It is far from enough to determine a person's weight and weight. What impact does the
environment have on our fat and thinness?
The right genes may become fat when encountering the right environment. Genetic factors are complex, and environmental factors are the same. But it mainly revolves around the two aspects of reducing calorie consumption and increasing calorie intake. In terms of reducing calorie consumption, more vehicles and labor-saving tools and changing their working methods will reduce people's calorie consumption.
and even the heating cost is reduced. People often stay in a warm environment, which will also reduce people's calorie consumption (people consume more calorie in cold environments). Watching TV and sitting for a long time and moving less can also significantly reduce calorie consumption.
Moreover, sitting on the sofa watching TV will not only reduce people's calorie consumption, but also may increase calorie intake. Because many people eat snacks while watching TV. Some studies estimate that people increase their caloric intake by more than 160 kcal per hour when watching TV [24]. Watching TV can even disrupt the signal of satiety inside the human body, allowing us to keep eating [28, 35].
In terms of changes in dietary structure, such as the increase in animal foods with high fat and low fiber, it will lead to factors such as increasing food intake, which will lead to a tendency to become fat. Research on in this regard is rich in evidence [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23].
They say that fat will not make people fat, and these evidences themselves are enough to refute his statement. Increased portion size in a single meal and eating large portions of food are also a factor that leads to an increase in dietary calorie intake (more than 50% of normal intake) [25]. Moreover, there are studies that the amount of food eaten has a clear relationship with BMI. The larger the food, the greater the BMI [29, 30].
There is a very interesting experiment here called the "bottomless soup bowl" experiment.
Researchers designed a special bowl. We ordinary people say that it is a mechanism. When there is still 1/4 of the soup in the bowl, it will be refilled automatically, but those who drink the soup will not realize it. In other words, the subjects of the experiment thought that there was only one bowl of soup, but in fact, this bowl of soup would never be finished.
So, when the subjects were drinking soup, they unknowingly drank 73% more than usual (113 kcal), but they did not feel that they drank more than usual, nor did they feel that they could last [37].
This means that when people decide how much they should eat, they often rely on a visual hint to judge, that is, to see how much is left in the bowl. Therefore, eating large portions of food will make people involuntarily eat more (the single portion of fast food is getting bigger and bigger).
Dietary diversification will also lead to an increase in calories intake [26].
There are experiments that feed animals with different flavors of feed, and the experimental animals will consume 25% more energy and increase their weight [31]. People who eat different foods within a few days or months consume more energy than those who eat a single food [32, 33].
Actually, this is not surprising. In layman's terms, eating the same kinds of things every day will make you tired of it after eating for a few days and you will be full as soon as you eat it. In academic language, this is called " sensory specific satiety ".
Sensory specific satiety means that when you eat something, people's pleasure in the taste of this food and sensory attention will be reduced and they will not like it so much. And you have a high sense of taste and a high degree of attention for things you have never eaten.
Therefore, if you often eat a few limited foods, these things will taste less, and people's interest in these foods will also decrease, making people eat less. Their low-carbon diet is also a restricted diet type.
Those who have really read their books will know that they have very strict restrictions on food types, and they cannot eat them, and there are only a few that can be eaten. This will make people eat less invisibly. The increase in the number of meals outside is also a reason for increasing calorie intake, and it is related to obesity [34].
has data reports. From 1977 to 1978, eating out caused a daily calorie intake to increase by nearly 300 kcal/day [27]. Although this is an old data, it can reflect basic rules.
or even, the increase in the number of people who eat together will also lead to an increase in calories, and a maximum meal can increase by 400 kcal [36]. That is to say, the more people you eat, the more you are likely to eat.
This is called " energy intake population promotion phenomenon ". This is also a proven factor that causes obesity in modern people. In addition, eating snacks, not eating breakfast, stressful eating caused by stressful life rhythm, etc. are all possible reasons for environmental factors that cause increased calories intake and thus obesity. There are many factors in this regard and countless research studies, so I will not give examples one by one.
We can use the following chart to summarize the impact of the environment (which also includes some genetic control factors) on energy balance. We can see that the relationship is very complicated. This model is just a simple summary focusing on the aspect of environmental factors.
If you fight against genes and environment, you won’t make yourself fat so easily
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My next article has also been updated. Everyone is welcome to see how carbohydrates are not easy to make people fat. What is the truth about high insulin?
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［37］：Wansink B, Painter JE, North J. Bottomless bowls: why visual cues of portion size may influence intake. Ones Res. 2005, 13:93-100.
