If there were no parasitic factors, the problem would be relatively simple.
A lot of exercise, horizontal bar, parallel bars, dumbbells, these endurance training are all possible, and there are many such articles, of course, the premise is patience and perseverance.
As for diet, I don't think it's very complicated. Even monks can be strong, so can you. Of course, you should basically balance your diet. Vegetables are big heads, because vitamins B 1 and B2 are essential substances for protein and carbohydrate consumption, and of course, protein, that is, eggs, milk, soybeans, lean meat and so on.
However, we must pay attention to the fact that what we eat can be consumed or converted into muscle through exercise. If it is simply stored in the form of fat, it will have a bad influence on the body.
Diet is not a problem for the current economy, so everything depends on will.