Dietary researcher: A recent study reports that laboratory animals that were fed reduced-calorie diets lived longer than laboratory animals whose caloric intake was not reduced  In response, some doctors are advocating reduced-calorie diets, in the belief that North Americans' life spans can thereby be extended  However, this conclusion is not supported  Laboratory animals tend to eat much more than animals in their natural habitats, which leads to their having a shorter life expectancy
Restricting their diets merely brings their caloric intake back to natural, optimal levels and reinstates their normal life spans
Some North Americans who follow reduced- calorie diets are long-lived.