Protein and Steroid... Builds muscle.. How do they differ?? | Eating 101 | Forum

I know nothing about steriods except that they are illegal and protein is not.  I think they have nothign to do with each other – one is a hormone and one is a macronutrient.  But regarding protein:

Basically your muscle is protein.  But more importantly, it needs protein (amino acids) to repair after damage (lifting).  So that's why eating a lot of protein is important if you are exercising.  And eating carbs with the protein has been shown in numerous studies to speed and increase the delivery of the protein to the muscles if you eat both near the time of your workouts.

"Too much protein" wont' get stored as fat except in the case of too many overall calories.  Just like "too much fat" won't get stored as fat unless you are eating too many calories.  (Fat is high in calories and can't really be converted to muscle, so you do need to watch how much fat you eat.)