Eat more and exercise less, eat on time and reasonably, and don't overeat. Drink more full-fat sweet milk or soy milk powder before going to bed every day. If boys need muscles, they should keep exercising. The amount of exercise every day is not very large. It is important to do it every day, such as dumbbells and push-ups. You can only do 20 on the first day, 2 1 on the second day, and one every day. I hope you will naturally gain weight after a long time.