Multiple large scale studies consistently demonstrate that healthy diets consisting of whole foods [not processed or sugar foods] rich in fruit, vegetables, nuts and legumes reduces the risk of mortality [i.e. all causes of death].
Victoria Miller, Andrew Mente, Mahshid Dehghan, et al. Fruit, vegetable, and legume intake, and cardiovascular disease and deaths in 18 countries (PURE): a prospective cohort study. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)32253-5/fulltext?elsca1=tlpr