Caloric Restriction and Anti-Aging: An Evolutionary Perspective

Introduction: Diet optimization represents a promising non-pharmacological intervention to delay the normal process of aging, and age-related conditions such as Alzheimer's disease and other dementias. Caloric restriction—that is the limiting of daily nutrient ingestion to under 2000 kcal/day in humans—has received significant attention as a promoter of anti-aging. Caloric restriction has been shown to extend lifespan in organisms such as C. elegans, D. melanogaster, non-primate mammals, and, more recently, humans. In particular, caloric restriction has a protective effect on cognitive performance. While it is possible that caloric restriction acts to extend lifespan by preventing disease associated with obesity, mechanisms independent of chronic disease prevention exist for its role in anti-aging. However, there has been less focus exploring the evolutionary reasons why organisms developed mechanisms that engender the anti-aging effects of caloric restriction. We propose that past the age of reproductive viability, caloric restriction serves as a means of kin selection, whereby nature has selected individuals who require fewer calories to survive and thrive in old age. These individuals can then support their families without significantly depleting available nutrients.