People following a 5-2 diet would eat lean protein and non-starchy vegetables two days a week. Heather Rousseau/NPR hide caption

itoggle caption Heather Rousseau/NPR

A typical Swedish meal of fried herring and lingonberries includes some of the local ingredients of the healthy Nordic diet prescribed in a new study. iStockPhoto.com hide caption

itoggle caption iStockPhoto.com