Modern people are basically hungry to lose weight, or because they are too busy to eat. Not eating so many delicious foods in the world really loses the meaning that it took thousands of years for human beings to stand at the top of the food chain. The human body is most sensitive to hypoxia and can only endure it for a few minutes. As long as oxygen and water are fully supplied, it can still survive for about 50 days under the condition of complete food hunger. In the early stage of short-term hunger or starvation, for example, when people don't eat for 1 ~ 3 days, the human body first has a strong sense of hunger, and the heart cavity shows a weak sense of discomfort and appetite, which is mainly caused by the stimulation of periodic peristalsis and contraction after gastrointestinal emptying and the stimulation of changes in body fluid components. However, for people who are hungry for a long time and are overtired, the sense of hunger is suppressed and obviously reduced.

As glycogen and blood sugar in the liver decrease obviously, insulin secretion decreases and glucagon secretion increases, thus strengthening catabolism and promoting gluconeogenesis to ensure the supply of glucose, which is the first need of the brain. In the whole process of hunger, the physiological protection of human body is very prominent, that is, strengthening the decomposition of minor parts such as muscles and ensuring the nutritional needs of important organs such as brain, central nervous system and heart.

Hunger persists and enters a state of chronic hunger. In addition to the above-mentioned characteristics of biochemical metabolism, the human body has the following changes: ① Fat mobilization and ketone body production and utilization are further strengthened, protein decomposition is reduced, and blood sugar level is maintained. ② The negative nitrogen balance in the early stage of starvation was relieved, and the urine nitrogen content dropped to a relatively stable low level. ③ The utilization of ketone bodies is enhanced, especially in the brain. ④ The gluconeogenesis of kidney is obviously enhanced, almost equal to that of liver, and the glutamine released by kidney is increased. The amide nitrogen and amino nitrogen released by glutamine promote the discharge of hydrogen ions in the form of ammonia, thus improving ketosis and acidosis.

People who are hungry for a long time show a decrease in the intensity of organ activities, such as slow heartbeat, shallow breathing, decreased muscle activity, decreased sexual function, and decreased overall material metabolism level, and the low-level functional activities that the body basically needs to maintain life. Although the weight loss rate decreases with the increase of hunger time, it is not as much as the calorie consumption, which shows that the decline of metabolic level is not entirely caused by weight loss. Further research also proves that mild food deficiency can sensitively affect the metabolic level, but it does not necessarily cause pathological reaction, so we can further understand the influence of nutrition on the body's development and health quality.

Rice is still delicious. Whether you are losing weight or working, you need a healthy body as a support. Once the body collapses, everything is useless.