Because the residence time of food in the stomach is about 1 hour for sugar, 2-3 hours for protein, and 5-6 hours for fat, you should start running or exercising at least 1 hour after meals, but you should be flexible. For example, when you feel thirsty, drink some water after meals, and you can't copy it mechanically. There are several things you shouldn't do after dinner:

First, don't eat fruit right away. Fruits contain brass-like compounds, which are converted into dihydroxy benzoic acid by intestinal bacteria after ingestion, while vegetables contain thiocyanate, which interfere with thyroid function under the action of these two chemicals and can lead to non-iodine goiter.

Second, don't drink tea at once. Because the tannins contained in tea combine with protein and iron in food to form colloid or precipitate which is not easily absorbed, iron deficiency anemia and protein's disease may occur in the long run.

Third, don't do strenuous exercise right away. During strenuous exercise, the blood flow of limbs increases, which affects the blood supply of gastrointestinal tract, affects the secretion of gastric juice and makes food indigestion. At the same time, the stomach volume becomes larger after meals, and exercise will cause gastroptosis.