Reasons for weight loss failure: The effects of hormones, insulin, and leptin

In the discussion of basal metabolic rate, we learned about the importance of lean body mass and basal metabolic rate. Therefore, increasing lean body mass to lose fat and gain muscle, and thus increasing basal metabolic rate, is an issue that dieters should pay attention to.

Recently, I saw this information online, complete with pictures and text. It stated that the human body is like a ship, following the laws of thermodynamics: calories in, calories out. Weight gain occurs because calorie intake exceeds calorie expenditure, and to lose weight, one must eat less and exercise more. This statement is correct, but not entirely accurate. When managing body weight, we often talk about losing weight, not just losing fat. This is actually correct; it's easy to see that obesity is related to fat. Therefore, the root cause of obesity is a problem with fat metabolism, leading to fat accumulation in the body. What causes this fat accumulation? Let's analyze it step by step.

From a dietary management perspective, when your body needs calories but can't get them, its regulatory functions will slow down metabolism to reduce energy expenditure, rather than converting body fat into energy through complex biochemical reactions. Therefore, eating less only reduces the body's energy expenditure, not fat loss. On the contrary, prolonged dieting can cause the body's regulatory functions to perceive a famine and try to store fat. Furthermore, our three meals a day stimulate three hours of energy metabolism. If we diet, skipping a meal means giving up three hours of this metabolic time. In our bodies, fat metabolism produces negligible calories; calorie metabolism primarily relies on muscle. Therefore, in a famine, the body sacrifices muscle to preserve fat; reduced muscle mass leads to a decreased basal metabolic rate. Once dieting becomes unsustainable, even eating the same amount of food as before will be perceived as overeating by the body, which will then convert these extra calories into fat and store them, resulting in weight gain instead of weight loss.

From the perspective of changing body fat percentage, everyone has a metabolic control point, and this control point is different for everyone. People with a faster metabolism have a lower control point than those with a slower metabolism. This control point does not depend on the amount of calories consumed or burned; weight gain occurs because the control point has risen. As early as the 1950s, American physiologist Kendy proposed the weight control point hypothesis. He believed that, like body temperature, the body shivers when cold and sweats in the sun to maintain a constant body temperature. When the body detects that your weight is below a predetermined value, it will increase appetite and reduce exercise to bring your weight back to a so-called normal state. This so-called normal state is what we need to maintain body temperature. Basal energy expenditure is the expenditure necessary for survival, and for people who lack exercise, this expenditure accounts for the majority of total energy expenditure. Even if your total daily food intake remains the same, a slight increase or decrease in basal energy expenditure over a long period can cause a dramatic change in your weight. Therefore, people with the same weight may have very different daily basal energy expenditures. To illustrate, imagine a clogged sink as a water tank. When the tank is clear, water drains quickly; the more you pour in, the more it flows out. But when the tank is clogged, too much water overflows. So, what do you do when the sink is clogged? Generally, three methods are used: First, limit daily water usage, allowing small amounts to seep through the clog; second, continuously scoop out water with a ladle to prevent further blockage; and third, take steps to unclog the drain, which is the most fundamental and effective solution. Similarly, when we eat the wrong foods, the hormones that regulate metabolism become blocked, causing the weight control point to rise. Dieting is like limiting daily water usage, while increasing aerobic exercise is like scooping out water with a ladle-neither is a long-term solution. Therefore, your failure to lose weight isn't due to a lack of willpower, but rather a failure to identify the root cause: physiological reasons. Why don't we fix the clogged drain? A clogged drain is like blocked hormones in our bodies. To restore normal hormone levels, it's important to adjust the ratio of muscle to fat in our bodies-that is, to adjust our body fat percentage, so that our bodies can achieve a relatively stable, lean physique.

From the perspective of insulin, produced by the pancreas, it determines whether our body stores or burns fat. When blood glucose levels rise, the pancreas releases insulin, which tells cells it's time to absorb glucose, because excess glucose in cells will be converted into fat. If there's too much glucose in the blood, the pancreas releases excessive insulin, leading to insulin resistance. Too much insulin prevents cells from burning fat. Another hormone is leptin, which inhibits excess fat. Our adipose tissue signals the brain about fat storage. If there's too much fat stored, it releases large amounts of a hormone called leptin, telling the brain to control appetite and stimulate exercise. From this perspective, leptin is produced by fat cells. If there's too much glucose in the blood, leptin's function is affected. Even with a lot of fat, a person may still have a good appetite and lack the desire to exercise, leading to an increased body fat percentage. To ensure better and sufficient leptin production, regular rest and adequate sleep are essential.

From a nutritional perspective, as I learned in my other self-health management manual, "Eating Healthier," 1 gram of oil is equivalent to 9 calories. Foods like white bread, white rice, noodles, pizza, desserts, cookies, soft drinks, and beer are highly efficient at converting into calories, quickly raising blood glucose levels and providing a rapid energy boost. However, they don't provide satiety for long, easily causing hunger and failing to provide adequate nutrition. Therefore, these foods are considered "red flag foods," and we should try to eat low-fat options.

From the perspective of fat cells, weight gain is closely related to increased fat storage. Research by Professor Hirsch, an expert at Rockefeller University studying changes in fat content, found that obese patients have 10 times more fat cells than ordinary people, reaching as many as 250 billion, and their volume is also 4 times larger. The way people store fat differs at different stages of life. When we are young, we prioritize increasing the number of fat cells; in adulthood, we fill existing fat cells. If there are too many of these cells, it is obviously difficult to maintain a slim figure. The increase in body fat snowballs, reducing basal metabolic rate. A high body fat percentage also means a high visceral fat percentage. Visceral fat fills the abdominal cavity, inhibiting intestinal peristalsis and preventing the elimination of toxins and harmful substances from the body, thus affecting health.

From the perspective of gut microbiota, research shows that weight is also related to gut bacteria, as these bacteria promote the digestion and absorption of food. In 2004, researcher Gordon found that germ-free mice, while consuming 29% more food than their twins, had 42% less body fat and a 27% lower basal metabolic rate. When these slender mice were returned to a normal environment from the germ-free environment, their weight returned to the same level as their twins within two weeks, but their food intake decreased. How does the body know about weight changes? Actually, our fat distribution sends signals to the brain about fat storage. If there is excessive storage, it releases a small amount of a hormone called leptin, which tells the brain to control appetite and may even stimulate your interest in exercise; otherwise, it remains silent.