That is why you have cheat days on a lifting diet, so you get some fats in your system!!! But eating enough steak, eggs, and even yogurt will put put some level of fat in your diet, thus sustaining growth!!! Complex carbs, moderate levels of FAT, AND HIGH PROTEIN, ARE KEYS....not fat alone...besides, the POLY, and MONO UN saturated fats are the ones you wanna intake more of, and SALMON, FLAX SEED OIL(1000mgs x3 servings) and other OMEGA 3 sources will help with this!!!!