ABSTRACT
This chapter contrasts with much of the book in that instead of focusing on treating obesity, we discuss the effects of lowering body mass in animals that are not overweight or obese to start with. For the purposes of this chapter, caloric restriction (CR) is dened as limiting caloric intake while providing adequate micronutrients. It should be emphasized that we are not treating obesity but making relatively lean animals very lean while avoiding any malnourishment by increasing nutrient density of the diet. CR is unique in that it signicantly increases mean and maximal life span of a population. An important aspect of CR is that it does not simply prolong the survival of the organism in an aged or decrepit state-it actually confers a “young” phenotype to the organism. No other nongenetic interventions have emerged that produce similar benets.
