When building muscle, the more protein the better, right? While you're working to build muscle with exercise, protein should make up 10 to 35 percent of total calories for adults. Research shows there is no benefit to eating more protein than this amount and it can be harmful.Keeping muscle mass, on the other hand, requires a lot less protein than building new muscle. For example, the recommended dietary allowance for protein for the average adult is 0.37 grams per pound of body weight. ~ Berceste