I am 17 year old male. I am 5'11" and weigh 147lbs. Right now I don't really eat very well. Especially on school days, on which I usually only eat one meal (dinner) a day. I have been doing P90X's "Ab Ripper X" every other day, mostly because I like it and think it's fun. I am doing some pullups every other day. I could start running if I committed to it, although I do have trouble with my throat and lungs running in the winter. My diet is high in saturated fat, which I will not change. For dinners, I usually eat a good amount of fatty meat. Oh, and don't tell me not to eat all the fat. I am not going to change my intake of fat. I will try to cut back on sugar though. I am looking to know what to add to my diet.

Recently I heard that nutrition is important to muscle gain, so I what I want to know is: What exactly should I eat to gain muscle?.