When caloric intake is reduced as much as 50%, the effects have been shown to be:
- Longer lifespan.
- Lower incidence of cancer.
- Slower onset of age-related dementia.
- No ovulation (reduced reproductive capacity).
The lack of ovulation is typical when diet is restricted (as in anorexic women). Although the positive effects of caloric restriction are negligible in social animals such as humans, the effects in rodents, insects, and microbes are remarkable. The lifespan of a praying mantis is in some cases doubled when the praying mantis is calorically restricted.
There are two well-respected explanations:
- Since organisms devote most of their energy to reproduction, when the reproductive organs shut off then more energy is available for other functions. This has a positive effect on health.
- When less food is processed, less free radicals are digested and generated. Since free radicals damage mitochondria and reduce efficiency of cells, having less free radicals means that cells will function better and longer. As a result, the being as a whole will be healthier.