Xingu Indian Men are characterized by being muscular and robust.  Their physical characteristics are a result of genetics, life style, and diet.  Some anthropologists have even hypothesized that competitions, such as Huka-Huka wrestling has selected for genes favoring more muscular individuals.  However, their diet and activities might more accurately account for their muscular physiques.  Many Xingu men practice wrestling on a daily basis in order to develop their musculature.  In addition, their diet is principally fish, a high protein source making muscle mass gain more probable than would a diet primarily consisting of carbohydrates.