In order to live longer - eat plenty of fruit and vegetables and cut back on the red meat. It is reassuring to know that we won't have to starve ourselves in order to live longer, as researchers are looking for drugs that imitate the positive effects of calorie-restriction, from PhysOrg.com:
"Physiological changes associated with ageing include cell damage and the emergence of cancer cells. The most important effects of low calorie diets and longevity therapeutics given late in life may not be to prevent this damage, but instead to stimulate the body to eliminate damaged cells that may become cancerous, and to stimulate repair in damaged cells like neurons and heart cells. Low calorie diets drive the body to replace and repair damaged cells. This process usually slows down as we age, but low calorie diets make the body re-synthesise and turn over more cells – a situation associated with youth and good health. Dr. Spindler and his colleagues used their screening method to search for drugs which cause pre-cancerous and cancerous cells to commit suicide and to replace those cells with new, healthy cells. It is thought that the body does this because it normally kills some cells like damaged and rogue cancer cells to provide energy when it is starving. Then it replaces these cells when a meal is eaten."
It occurs to me that a drug that made you feel less hungry would do essentially the same thing, although this could have rather unpleasant side-effects.
It also seems that you should eat a very nutritious diet on top of the calorie-restriction.