Exercise a little, gradually. Choose what suits him, and he won't hate pain. Swimming, skipping rope, walking, jogging, playing badminton, table tennis, basketball and football. It is a sport when children play together.
Give priority to with fruits and vegetables, meat, eggs, milk. It is best to drink skim milk, 2 eggs a day. Bean products industry needs it.
Purple is the best vegetable, of course, other vegetables are also good, and they eat differently.
Staple food, eat coarse grains several times a week. Or make some delicious coarse grains, corn porridge pressed in a pressure cooker, and put red beans and black beans in it.
Coarse grains are more to his taste than flour and rice.