It isn't so much diet as having to seriously tax your muscles and to allow a minimum of 24 complete hours of rest. The taxing of the muscles(sprinting & weight lifting) causes microtears and sends a signal to build more muscle. The actual building of the muscle occurs during rest. If you do not adequately rest, you will not build muscle at a good rate or perhaps not at all depending on how much exercise you do. If you are looking for bulk you need to do low reps/high weight. The final rep should be at a level that causes muscle failure(as in you cannot lift any more, not even an ounce). It is this muscle failure that stimulates muscle growth. Also in between sets, you should rest at least 30 seconds but not more than 90 seconds. If you do not currently lift, I wouldn't go to muscle failure for the first week. You could risk injury this way, until you get an idea as to what you can safely lift.