The Mediterranean diet, listed second for overall healthiness by U.S. News (but formally ranked as tied with DASH), fares little better on the evidence. Highly popular since its formal introduction in 1993 by the Harvard School of Public Health and selected by the U.S. Department of Agriculture in 2015 as one of its three recommended "dietary patterns," the diet has principally been studied in one 2013 trial, on about 7,500 subjects in Spain. After five years, those on the diet had reduced their risk of cardiovascular events by an underwhelming 2%, in absolute terms. Moreover, the diet had no impact on overall mortality or weight loss. And the trial itself was flawed; it didn't have an adequate, comparative control group.

Source: Los Angeles Times January 28, 2018 12:11 UTC