Aging is accompanied by a marked increase in hepatic resistance to the action of insulin. In rats, CR for 18 monthsrestored hepatic insulin sensitivity to the same levels observed in young rats (4 months) . Similarly in rats selectively bred for low aerobic running capacity there is an age related development of the metabolic syndrome,
including hyperinsulinemia, insulin resistance, visceral obesity, and dyslipidemia. Hyperinsulinemia in these rats is associated with impaired hepatic insulin clearance. These metabolic abnormalities were reversed by 30% CR for 3 months. The increase in age related insulin resistance may be associated with the age related increase in fat mass, in particular increases in visceral fat (VF)