A New Book Examines Why and How We Age
Research on mice, flies, and other animal models has shown that following an extremely low-calorie diet can increase their life span by as much as 35 percent. Does this mean that people could extend their lives by eating less?
This is being addressed right now in various studies of human volunteers. One thing is clear; if you are obese and diabetic, then exercise and diet are really important. Whether someone who is in good health would benefit from a severe calorie restrictive diet isn't clear. There are also risks with becoming too thin. Just look at anorexia nervosa.
Is there a maximum limit on how long humans can live?
It's an open question. All I can say is that there's been this remarkable increase in the last 200 years of survival to advanced ages. Demographic studies don't seem to indicate any slowing in this increase, at least in favored populations.
On the other hand, there are global deteriorations in the environment. The amount of airborne pollutants is increasing everywhere, and there are direct relations between the rate of vascular disease and the level of air pollutants. It's by no means certain that the lifespan increases of the last 200 years will continue at the same rate or be available to all people. My own hunch is that lifespan could increase considerably more, but it may depend on finances and access to top-level medical resources.