Seems like everyone at the gym is doing it: filling up on protein to bulk up those biceps. But it's a misconception. Eating extra protein actually doesn't do much toward boosting your muscle mass and strength.

In fact, medical research shows that consuming too much protein -- more than 30% of your total daily caloric intake -- could actually harm your body, says protein expert Gail Butterfield, PhD, RD, director of Nutrition Studies at the Palo Alto Veterans' Administration Medical Center and nutrition lecturer at Stanford University.