First, if you want to gain muscle, then add some carbohydrates and protein half an hour before fitness. Hypoglycemia is easy after exercise, so add some carbohydrates before fitness.
Second, if you want to lose weight, try not to eat or eat less for two or three hours before exercise.
From the time point of view, exercise before dinner is the best, and the most energetic time is before dinner, that is, from three to five. If you choose to exercise after dinner, it will be one hour after dinner. Inappropriate exercise will affect gastrointestinal digestion, which will affect gastrointestinal function in the long run.
It is best to exercise three hours after dinner, because the pressure on the stomach just after dinner is relatively high, and it is very harmful to the stomach if you exercise immediately. You can't eat until about an hour after exercise. At this time, the body's metabolism is basically stable, which is conducive to the absorption of food.
After exercise, you can add some food: for example, drink milk, eat beef, chicken and fish, preferably egg whites. You can eat some fruits before exercise, such as apples, oranges, lemons and other substances rich in Vc.