Feed Your Muscles

Lifting weights makes your metabolism race as your body works to replenish energy and repair muscle tissue. "If you don't take in enough calories and protein, you won't have the resources you need to recover," says Durkin. He recommends consuming 300 to 500 additional calories on workout days, and skewing those calories toward protein, the building block of muscle. "Shoot for 1 gram per pound of body weight," says Durkin.