This study will determine the effects of supplementing beta-hydroxy-beta-methylbutyrate (HMB) on body composition and strength changes during weight loss. When overweight and obese persons lose weight, and in particular in conjunction with dietary restrictions, muscle, bone mass, and muscle strength are also lost. HMB has been shown to preserve muscle mass and strength, and it is thought that HMB may also preserve muscle, bone, and strength during weight-loss.