That seems rather short sighted. Much of the increase in mean lifespan from 150 years ago comes from lower number of deaths at infancy (aka doctors washing thei

That seems rather short sighted. Much of the increase in mean lifespan from 150 years ago comes from lower number of deaths at infancy (aka doctors washing their hands). You can probably attribute most of the rest to improved nutrition and antibiotics. The philosophy behind "paleo" and various fasting regimens (as well as different modalities of physical training) is that living close to what our primate ancestors lived like is probably something like optimal. Starving yourself from time to time, something which is actually practiced by almost all agricultural societies as a form of religious devotion, is probably a good idea. The whole "3 square meals" thing is mostly a product of marketing departments rather than any scientific research.