MODEL RELEASED. Male Pima Indian undergoing underwater method for measuring percentage of body fat. The underwater method corrects for residual air volume in the lungs. Obsesity is related to high blood cholesterol & a propensity for an increased risk of heart diseases. The population of Pima Indians of the Southwestern U.S. displays a high level of obsesity. However, they have a significantly lower rate of heart disease, compared to that of the Caucasian population. The Pimas were used as a trial group in this study at the NIH's Clinical Research Section in Phoenix, Arizona, to study the relationship between obesity & cholesterol & their relation to heart disease.