Calorie restriction and aging: a life-history analysis

Area of Science:

• Evolutionary biology
• Gerontology
• Life-history theory

Background:

• The disposable soma theory posits aging results from natural selection favoring reduced investment in somatic maintenance.
• Calorie restriction in rodents extends lifespan and retards aging, suggesting an adaptive response.

Purpose of the Study:

• To test the hypothesis that calorie restriction's life-extending effects are an adaptive response involving resource allocation shifts.
• To model how shifts in resources between reproduction and somatic maintenance influence aging and survival.

Main Methods:

• Developed a mathematical life-history model of dynamic resource allocation.
• Modeled senescence as a state change dependent on maintenance resources.
• Assumed individuals allocate resources to maximize total descendants.

Main Results:

• The evolutionary hypothesis is plausible under specific conditions.
• Two key factors favor this adaptive response: reduced juvenile survival during famine and an energetic cost for reproduction.
• Without these factors, there is no evolutionary advantage to prioritizing maintenance over reproduction.

Conclusions:

• The model supports the idea that resource allocation shifts can explain life extension under calorie restriction.
• The findings suggest that the benefits of calorie restriction may extend to other species, including humans.
• This research provides a framework for evaluating the evolutionary basis of aging and lifespan extension.