Regardless of which muscle group you're trying to build, a healthy dose of protein in your diet is vital. You can get protein from a number of sources including meat, fish and dairy, but bodybuilders are known to incorporate protein shakes into the mix during heavy training.
Generally speaking, adult men need about 56 grams of protein a day; women need 46 grams [source: WebMD]. Athletes need a bit more because physical exercise breaks down muscles. Depending on your exercise regimen, you may need to add as much as 50 percent more protein to your daily diet while training and building muscle [source: Nierenberg].