Here are half a dozen studies on diet (see below for all abstracts and links). The first three are about the benefits of healthy lifestyle. Trichopoulou & colleagues evaluated the contribution of nine widely accepted components of the Mediterranean diet (high intake of vegetables, fruits and nuts, legumes, fish, and cereals; low intake of meat and dairy; high ratio of monounsaturated to saturated lipids; and moderate intake of ethanol) in the inverse association of this diet with all cause mortality. They concluded that "The dominant components of the Mediterranean diet score as a predictor of lower mortality are moderate consumption of ethanol, low consumption of meat and meat products, and high consumption of vegetables, fruits and nuts, olive oil, and legumes.