For general meals, exercise is best arranged after meals 1 hour. If you eat a very rich meal, you'd better exercise after 2 hours. The gastrointestinal tract needs to digest food, keep crawling, and secrete gastric juice and intestinal juice. At this time, it needs to have enough blood supply. If you start exercising immediately after meals, part of the blood in the gastrointestinal tract will be transferred to the exercise organs, and the blood supply in the gastrointestinal tract will be relatively reduced, which is not conducive to gastrointestinal peristalsis and secretion of digestive juice by glands, thus affecting the digestion and absorption of food. And after a full meal, the stomach is full of food, and the stomach is full. Even a slight exercise will affect the normal peristalsis of the stomach, thus affecting the digestion of food. Over time, it will lead to gastrointestinal diseases. If you just eat a snack before exercise, it doesn't hurt to start exercising immediately.