Studies have found that following a diet high in protein (especially Leucine) and low in carbohydrates, is an effective and safe way to lose weight. Leucine is an essential amino acid that cannot be made by the human body. Leucine must therefore be consumed through food such as whole wheat bread, brown rice, nuts, or supplements. One of the primary functions of Leucine is to help preserve lean tissue. This is vital to successful weight loss. Leucine works directly to prevent muscle loss during weight loss. When following a high protein diet high in Leucine, therefore, the majority of weight you lose is fat, not muscle. This contrasts greatly with high carbohydrate diets where much more of the weight loss is muscle.