Caloric restriction (CR) without malnutrition delays aging and extends lifespan in diverse species, but its effects on illness resistance and mortality in primates are unclear. A 20-year study in rhesus monkeys showed that moderate CR reduced aging-related deaths and delayed the onset of age-associated pathologies. At 50% of control animals survived compared to 80% of CR animals. CR also reduced the incidence of diabetes, cancer, cardiovascular disease, and brain atrophy. CR was shown to improve metabolic function, including insulin sensitivity and glucose homeostasis, preventing diabetes. The incidence of cancer was reduced by 50% in CR animals. Cardiovascular disease was also reduced by 50% in CR animals. Brain atrophy was significantly reduced in CR animals, with preserved gray matter volume in key regions. The study, conducted at the Wisconsin National Primate Research Center, involved 76 rhesus monkeys, with 37% of control animals dying of age-related causes compared to 13% of CR animals. CR animals had a 3-fold higher risk of age-related death than control animals. CR also delayed the onset of age-associated diseases, with control animals showing disease onset at 3 times the rate of CR animals. The study supports the idea that CR may provide long-term health benefits in humans, as similar effects have been observed in long-term CR studies. However, the effect of CR on maximal human lifespan remains unknown. The study highlights the importance of CR in delaying aging and promoting survival in primates.Caloric restriction (CR) without malnutrition delays aging and extends lifespan in diverse species, but its effects on illness resistance and mortality in primates are unclear. A 20-year study in rhesus monkeys showed that moderate CR reduced aging-related deaths and delayed the onset of age-associated pathologies. At 50% of control animals survived compared to 80% of CR animals. CR also reduced the incidence of diabetes, cancer, cardiovascular disease, and brain atrophy. CR was shown to improve metabolic function, including insulin sensitivity and glucose homeostasis, preventing diabetes. The incidence of cancer was reduced by 50% in CR animals. Cardiovascular disease was also reduced by 50% in CR animals. Brain atrophy was significantly reduced in CR animals, with preserved gray matter volume in key regions. The study, conducted at the Wisconsin National Primate Research Center, involved 76 rhesus monkeys, with 37% of control animals dying of age-related causes compared to 13% of CR animals. CR animals had a 3-fold higher risk of age-related death than control animals. CR also delayed the onset of age-associated diseases, with control animals showing disease onset at 3 times the rate of CR animals. The study supports the idea that CR may provide long-term health benefits in humans, as similar effects have been observed in long-term CR studies. However, the effect of CR on maximal human lifespan remains unknown. The study highlights the importance of CR in delaying aging and promoting survival in primates.