Increases metab rate
Muscle and fat weigh the same (pound of fat weighs same as pound of muscle); muscle is denser, so clothes fit better if one is leaner at the same weight.
more calories than does fat. Leaner body burns more calories, even at rest, because there is more metabolically active tissue. Often w/ crash diets
, there is xs loss of muscle, so you get more flabby w/lower weight.