Figure 1.

Calorie restriction impacts numerous physiological functions and parameters, which may ultimately affect health and longevity. The most heavily influenced physiological characteristics are presented in this flowchart. A few genes may mediate the impact of calorie restriction; the most fundamental ones are genes encoding nutritional sensors such as sirtuins (SIRT1–7), adenosine monophosphate–activated protein kinase (AMPK), and target of rapamycin (TOR) and genes involved in insulin signaling. Downstream effects of calorie restriction include decreases in cancer incidence, the suppression of reproduction, alterations of metabolic functions with increased fat oxidation, alterations of mood (higher degrees of anxiety and susceptibility to depression), increased aggression, and increased DNA repair. Calorie restriction robustly increases the longevity and health of laboratory animals; however, its applicability to humans is unknown.