Everyone should always try to follow the food pyramid, it will lead you to a healthly lifestyle. Although the food pyramid is very helpful, if you're are going to try to gain more muscle you will need supplements (Read "Supplements" for a list of supplements used by weightlifters). These supplements will greatly help you obtain the goals you have in mind. For instance you are looking to gain muscle mass without getting fat. You need to supplement your diet with extra protein, a great way to do this is through protein powders or bars. Protein is the bases for muscle growth. Keep in mind to follow the pyramid because you need Fat and Carbs to digest Protein. Try to eat atleast 5 meals a day (Protein shakes or bars can count for 1 meal), if you need to spread them out and eat a little less each meal. Your body will be constantly search for energy to repair your muscles. Make sure you take care of it!