After reviewing hundreds of studies on nutrition, diseases and longevity in laboratory animals and humans, the optimal diet for longevity has “lots of legumes, whole grains and vegetables; some fish; no red meat or processed meat and very low white meat; low sugar and refined grains; good levels of nuts and olive oil, and some dark chocolate,” reports University of Southern California gerontology professor Valter Longo. According to the literature review he and others authored for Cell, a day’s meals should ideally occur within a window of 11 to 12 hours, allowing for a daily period of fasting. A five-day fast or fast-mimicking diet every three to four months was also suggested to help reduce insulin resistance, blood pressure and other risk factors for those with increased disease risks.