Fat and thin, the right weight gives people a healthy feeling, not a healthy beauty. According to human instinct, people who were too thin in primitive times did not have enough fat to resist the cold and store energy. Too fat people didn't have enough speed to avoid danger and catch prey, which was extremely dangerous at that time. Nowadays, being too thin or too fat is often accompanied by some diseases, such as anemia, gastrointestinal digestive problems, hypertension, fatty liver and so on. Therefore, it can be said that the art of existence also exerts a subtle influence on human aesthetics.