SHC1 and overnutrition: Because the majority of studies initiate CR at a younger age than 18 months, and many of the studies indicating that Shc proteins may play a role in the metabolic response to overnutrition have been conducted in young animals [1, 5, 6], it was important to investigate the impact of Shc proteins on CR-induced changes in whole body energy metabolism in a younger adult cohort of mice.