Diet and Obesity: The Effects of Overeating and Nutritional Components

III. Diet and Obesity

While genetic factors are important, they are not the deciding factor. Environmental factors, such as dietary behavior, physical activity and exercise, psychological factors, and social factors, play a decisive role in the development of obesity.

Changing environmental factors is much easier than eliminating genetic factors, so people should focus on managing environmental factors.

For centuries, the role of food intake in obesity has been a point of contention in the field of obesity research, and many questions remain unanswered.

Do obese people eat more than average people? Why can't humans regulate their appetite? Which is more likely to cause obesity, fat or sugar? Is obesity simply due to overnutrition? Is there a relationship between diet and obesity? These questions will be addressed below.

(I) Overeating and Obesity

There are currently two diametrically opposed views on overeating and obesity.

Some scholars believe that obese people are obese because they eat a lot; those who hold the opposite view insist that obese people do not eat much and that their low basal metabolic rate is the cause of obesity.

However, the application of a new technology, the "water double labeling method," has revealed the secret that "obese people eat less," powerfully demonstrating that overeating is the main cause of obesity.

1. Overeating by the mother and fetal obesity: Studies have shown that if the mother often overeats during pregnancy, it will greatly increase the amount of insulin secreted after meals and prolong the peak secretion time. As a result, the mother's blood sugar will remain at a high level for a long time, and the fetus will obtain a large amount of glucose, which will induce the formation of fetal fat cells.

The formation of human fat cells is mainly completed during the fetal period. Therefore, when these children reach adolescence and adulthood, they are naturally much more prone to obesity than their peers.

2. Overfeeding and infant obesity; infant obesity is often caused by force-feeding children, feeding cereals too early, or feeding formula with too high a concentration or too much sugar.

If infants under 1 year old are overfed, it can cause excessive proliferation of fat cells, and the number of fat cells will not decrease due to subsequent fasting.

Therefore, obese babies are more likely to become obese as adults.

The survey results indicate that babies who weigh more than 12 kilograms at age 1 are much more likely to become obese as adults than babies who weigh less.

Growing up fast and growing well are not the same thing.

Other facts also prove that if an infant gains more than 3.5 kilograms every six months in the early stages, the likelihood of becoming obese later in life will greatly increase.

The causes of infant obesity involve many factors, including genetics, environment, and society, among which overfeeding is an inappropriate practice.

3. Overeating and obesity in adults: Some scholars still believe that overeating is not closely related to obesity. They point out that some obese people do not eat much, and sometimes even less than thin people. However, their methods of evaluating food intake mostly rely on patients' own reports, which lack objectivity.

A new technology called "water dual labeling" can accurately measure the energy consumption of the human body during free movement.

Measurements using this method show that obese people have a much higher average energy expenditure than people of normal weight.

Therefore, obese people do not have a low basal metabolic rate, and this basal metabolic rate is much higher than the calories they report eating, indicating that there is a problem of overreporting food intake among obese people.

Moreover, the more people fail to lose weight repeatedly, the higher their rate of lying is.

A questionnaire designed specifically for obese people also showed that obese people often neglect the food they eat.

4. Causes of overeating: To analyze the causes of overeating, we should first understand human eating behavior, that is, why do people eat? How do we regulate food intake? Why do we stop eating?

(1) Why do people eat? There are three reasons for eating: First, because I am hungry, and the search for food is a necessity for the body's energy metabolism; second, because I want to eat, due to the temptation of delicious food or emotional sustenance; and third, because it is time to eat, and eating is required by social customs.

In societies with abundant food supplies, eating is often not just about satisfying physiological hunger, but more often about satisfying the body's social needs.

(2) How to regulate food intake: The amount of food intake depends on the sensory properties of food, human cognitive factors and metabolic factors.

Food that looks, smells, tastes, and looks delicious often makes you impatient, causing you to eat faster and open your mouth wider. The tastier the food, the more you eat.

Southerners love to eat rice, while northerners love to eat noodles. If this is reversed, it often affects their appetite. This is related to cultural customs and perceptions.

After consuming a certain amount of carbohydrates, the concentration of serotonin in the blood will increase, inhibiting the intake of sugars. This is due to the effect of metabolic factors.

Therefore, the more delicious and palatable the food is, the more you will eat.

A single type of food reduces appetite, while varied meals tempt you to eat more.

(3) Why stop eating: Food enters the body and has two effects.

First, it makes people feel full and stop eating.

Because this effect is rapid, it is also known as the immediate satiety effect, which determines the amount of food consumed.

Secondly, it allows the body to maintain a state of satiety under certain conditions, without feeling hungry. It determines the interval between meals and is also known as the sustained satiety effect.

Instant satiety depends on how one perceives food. Monotonous and bland food shortens eating time and reduces food intake, while rich and delicious meals prolong eating time and increase food intake. Therefore, some people call it psychological satiety.

The sustained feeling of fullness depends on the changes in metabolic substances in the body after food digestion and absorption, also known as physiological satiety.

However, in human society, the timing of eating is greatly influenced by external environmental factors, and physiological satiety plays a relatively minor role.

In modern society, with the development of science and technology and the abundance of material life, the body's mechanisms to prevent insufficient intake are very strong, while the mechanisms to prevent overeating are weak and insufficient.

Therefore, overeating is extremely easy.

We shouldn't blame overweight people for eating too much; we should recognize that overeating is what causes obesity.

(II) Nutritional Components and Obesity

The body's energy needs mainly come from fats, proteins, and carbohydrates in food.

When a certain amount of carbohydrates and proteins are ingested, the body will promptly send signals to stop eating. However, when fat is ingested, the body's ability to respond in this way is very weak.

The content of the three major nutrients often determines the sensory characteristics of food. For example, high-fat and high-sugar foods are soft, delicious, and very tempting, which will increase appetite and food intake.

Therefore, whether or not we eat, how much we eat, and the feeling of fullness after eating are all closely related to the content of the three major nutrients in food.

1. Fat and Obesity: Edible fats mainly refer to various vegetable oils and animal fats.

In the past, some people believed that fat stays in the gastrointestinal tract for a longer time, which can enhance the feeling of fullness, so it is not as easy to make people fat as sugar. Fat is even the basis of some weight loss diets.

But this is not the case. Foods rich in fat are generally fragrant and delicious, with a good texture and taste, making you want to eat them and want to eat more, but they have a poor immediate satiety effect.

Moreover, fat has a high energy density (the energy released by the oxidation of 1 gram of heat-producing substance in the body), which is more than twice that of carbohydrates and proteins.

Even disregarding the sustained satiety effect of fat, the fact that fat has a poor immediate satiety effect and high energy density can greatly increase the body's energy intake.

Next, let's look at the sustained satiety effect of fat. An experiment was designed in which two groups of obese people were given a high-fat diet and a high-carbohydrate diet, respectively. The high-fat group consumed far more energy than the high-carbohydrate group (immediate satiety difference).

Then, the food intake on the second day was measured (with a balanced food selection), and the energy intake of the high-fat group was not lower than that of the low-fat group.

This experiment fully demonstrates that the immediate and sustained satiety effects of fat are not strong.

Epidemiological data further confirms that a high-fat diet can induce obesity, while a low-fat diet can reduce the occurrence of obesity.

Some people are afraid of gaining weight, so they avoid animal fats and eliminate all animal products, but this increases their consumption of vegetable oils.

In terms of providing calories, animal fats and vegetable oils have the same calorie value, meaning they produce the same amount of heat energy.

This is one of the reasons why some overweight people are still overweight even though they don't eat meat.

While reducing our intake of animal fats, we should not increase our intake of vegetable oils.

In addition, some hidden fats in food are often overlooked.

Various foods contain different amounts of fat or lipids. Plant-based foods such as peanuts, soybeans, and walnuts are rich in oils, while animal-based foods (meat, poultry, eggs, milk, and fish) all contain a certain amount of fat.

For example, 100 grams of walnuts contain 50 grams of oil, 100 grams of chicken contain 30 grams of oil, and only grains, fruits, and vegetables contain relatively little fat.