When faced with delicious food, people can't help but have the urge to eat a lot, and some even refuse to put down their chopsticks until they are stuffed.
However, a recent study by scientists has found that people who are consistently overfed are more prone to premature aging of the brain. It is said that long-term overeating leads to excessive calorie intake, excess fat, and high blood lipids in the body. This causes an increase in a substance called "fibroblast growth factor," leading to atherosclerosis of cerebral arteries. This reduces the supply of oxygen and nutrients to the brain, resulting in decreased memory, premature brain aging, and mental dullness.
So, where does our sense of hunger and fullness come from? What are the other dangers of long-term overeating? And what kind of diet is the most reasonable for us?
Modern medical research has found that so-called "hunger centers" and "satiety centers" exist in the human brain. Together with the cerebral cortex, they effectively control a person's food intake through reactions from the gastrointestinal tract.
When blood sugar drops and the stomach is empty, the cerebral cortex receives hunger signals. The nerve centers of the cerebral cortex then send an instruction to eat to the hunger center in the hypothalamus, while sending an inhibitory signal to the satiety center. This is when a person consciously starts eating. When a person has consumed a certain amount of food, the gastrointestinal tract feels full and sends a satiety signal back through a reflex. The cerebral cortex then sends "full" signals to both the hunger and satiety centers, thus stopping the eating.
Once, researchers conducted relevant animal experiments. They found that after destroying the satiety center in the animals' brains, the animals ate continuously, with a significant increase in food intake and weight. They would only stop when their energy reached a new balance. Conversely, when the hunger center was destroyed, the animals refused to eat for long periods and eventually died from exhaustion.
However, the amount of food one eats is also related to eating habits. Some people who are always greedy and eat too much are not always doing so out of hunger, but rather due to a long-established habit.
When dining, eating too quickly or for too long can lead to overeating. Difficulty controlling appetite when faced with favorite food is also a major reason.
When people gather for a meal or are distracted by other things while eating, they often spend a long time at the table—an hour, two hours, or even longer. This continuous eating, combined with the focus on conversation or other thoughts, leads to a relatively slow response to the feeling of fullness, resulting in excessive food intake and overeating.
In addition, if you wolf down your food, the speed of eating can outpace the transmission speed of the satiety signal. Even if the amount of food eaten is already sufficient, the brain has not yet received the signal, so you continue to eat nonstop, leading to excessive food intake.
In our daily lives, we can also have this experience: not feeling hungry at all, but still unable to resist the temptation to eat a little when delicious food is in front of us. This can also easily lead to overeating.
A large volume of food does not necessarily mean more nutritional intake. Long-term overeating can cause a series of reactions in the body, leading to various diseases.
Being full does not necessarily mean that the required nutrients have been sufficiently consumed. For example, eating a nutritionally unbalanced meal with a large volume and high fat content might still result in an insufficient intake of trace elements or vitamins. This can also be considered a type of hunger, known as "hidden hunger."
The most direct consequence of overeating is the increased burden on the gastrointestinal tract. If the stomach is always in a state of fullness, its capacity will expand, and its digestive and absorption functions will decline, easily causing indigestion. The large intake of fat and protein that cannot be effectively utilized will be stored in large quantities, leading to nutritional excess, obesity, diabetes, hyperlipidemia, and other diseases.
Some studies also suggest that the more energy the human body consumes, the more harmful reactive oxygen species (free radicals) are produced, and the faster the aging process. Eating less can reduce the production of reactive oxygen species, protecting cells from their damage and thus slowing down aging.
Furthermore, because modern people generally love to eat acidic foods such as meat and refined grains, excessive consumption can acidify the body's internal environment, creating an acidic constitution. This provides a fertile ground for the development of various diseases.
The daily amount of food to eat also has scientific standards, but it should be combined with the specific conditions of each individual.
For a 1.70-meter-tall young or middle-aged man of normal weight with not very heavy physical labor, his daily energy requirement is about 2200 kilocalories. Of this, grains should account for about 50%, which is about 300 to 350 grams. Meat should be 150 grams, including all types, plus one egg and 250 milliliters of milk. An appropriate amount of bean products should also be included, and other foods like mushrooms, wood ear mushrooms, kelp, seaweed, and dried shrimp should be eaten regularly.
As for oils and fats (including oil and plant seeds), it is recommended to avoid fried foods, and the total oil intake should not exceed 30 grams per day, which is 3 tablespoons.
Regarding vegetables and fruits, in terms of volume, they should be the largest, reaching 750 to 1000 grams.
In addition, snacks, desserts, and alcohol should be consumed in moderation. If physical labor is slightly heavier, these items can be increased accordingly.
In terms of age, the food intake of children in their pubertal development period will certainly be higher than this, as they are growing and have more physical activity than adult men. The elderly should reduce their intake accordingly.
Of course, everyone's physical condition is different, so their food intake will also vary. It mainly depends on one's own specific circumstances.