Investigators interested in the effects of aging on glucose metabolism are faced with a difficult problem. The population of modern, wealthy nations are, to a large extent, sedentary and have food of high caloric density readily available to them. As a consequence, it is now usual for people to progressively gain weight with advancing age up to ~65 years of age. In a large proportion of individuals, much of this gain in fat is in the truncal and intraabdominal regions and is, to varying degrees, associated with the metabolic abnormalities of the abdominal obesity syndrome, including insulin resistance and, frequently, type 2 diabetes (3, 21). This pattern has now come to be thought of as due to aging (1, 2, 10, 11, 27, 28).