Extending your lifespan may be as easy as eating less.  

Calorie

A chronic caloric restriction has been suggested by several studies as a means to reduce the aging process and extend life.  Most of these have been in mice or rats and more primitive species.  There is a bountiful amount of research to show that prolonged calorie restriction increases lifespan in rodents.  It is suggested that either a prolonged calorie restriction affects biomarkers of longevity or markers of oxidative stress or reduces metabolic rate beyond that expected from reduced metabolic mass and thus it reduces the stress not he body and extends life.  The has been limited research performed in humans or other primates.  

A recent study in lemurs study appears similar results in a primate species.  In the study, researchers exposed a group of mouse lemurs or Microcebus murinus to moderate chronic caloric restriction with 30% fewer calories than their peers consuming a normal diet[1].   This lemur study was performed on early adults already past their growth and development of childhood.  The scientists followed the populations for ten years, and longevity, age-related pathologies, cognitive abilities, motor skills and cerebral atrophy were then followed until their natural death.  The lifespan of the test subjects increased by almost 50%, and the group appeared to lose more grey matter buy less white matter than the control group.  The lost of grey matter has an unknown significance.  The median survival is 9.6 years as opposed to 6.4 years for the control group.  This change was significant statistically.  

One prior study looked at markers of human aging in caloric restriction, but it did not look at the effects of aging[2].  The study was only six months long, so it was insufficient to determine true effects on aging.  

The bottom line: The results of this study indicate that chronic caloric restriction is currently the most effective way to extend maximum lifespan.  It is unclear what sort fo results we might see in human, but we expect them to be similar.   A delay the aging process could have a significant impact on health care costs in the United States.  Human trials are needed, but this is one more reason to consider losing weight.