First of all and most important...fat and carbohydrates are never and will never turn into muscle. There is no metabolic reaction to make that happen. It would be nice if it could happen though. :) Anyways, most of your calories will not come from protein as far as percentages go, but you should be eating more protein than the average person is consuming just maintaining their weight. A safe level is about 1gram of protein/lb of body weight while working out hard. A lot of people like me(who weighs about 225lbs) find that hard to do so you could use a supplement if that is easier. Skinless Chicken Breasts and tunafish are great though. I hope I helped you.