Roger, you can try calorie restriction which has proven to extend
lives of some animals by about 50%. Scientific American did an article
about this.

http://www.sciam.com/article.cfm?art...mber=1&catID=2

Excerpt:

Our hunt for cr mimetics grew out of our desire to better understand
caloric restriction's many effects on the body. Scientists first
recognized the value of the practice more than 60 years ago, when they
found that rats fed a low-calorie diet lived longer on average than
free-feeding rats and had a reduced incidence of conditions that
become increasingly common in old age. What is more, some of the
treated animals survived longer than the oldest-living animals in the
control group, which means that the maximum life span (the oldest
attainable age), not merely the average life span, increased. Various
interventions, such as infection-fighting drugs, can increase a
population's average survival time, but only approaches that slow the
body's rate of aging will increase the maximum life span.