Weight loss is common in athletes and is typically practiced with the goal of increasing the efficiency of movement and thus enhancing performance. Weight loss can be accomplished “passively”, making use of nutrition strategies only; i.e. by restricting energy intake. Several ‘diet-only’ plans have been examined in head-to-head studies, confirming there are a variety of dietary patterns which promote weight loss; all of which must create an energy deficit. However, weight loss via diet alone results in the loss of both body fat and lean tissue, which would likely include skeletal muscle and potentially the loss of bone mass. In addition to diet-only strategies, weight loss can be accomplished through increasing the volume/intensity of exercise without changes in dietary intake, or as is more common, in combination with a reduction in energy intake. Optimizing both the quantity and timing of protein intake can help mitigate losses in muscle mass. In addition to protein intake and exercise, the speed of weight loss, and hence the magnitude of the caloric deficit, can affect the ability to retain lean mass. In fact, with substantially large caloric deficits, increases in dietary protein may show diminishing effects in mitigating losses of lean tissue mass.