Best food to eat for building muscle?

Sensibly: Plenty of lean protein. Avoid greasy, sugary and very salty stuff as you probably want lean muscle unless you're planning to be a football linebacker. After a workout, 20 grams of protein's a good snack -- it can be your whey / soy powder, some lean fish or chicken or tofu. The key is in the exercise rather than the diet. Glad you're doing this. Best wishes.