5 (tie): MIND diet

The MIND diet, which claimed the No. 3 spot last year, focuses on foods that help your brain — specifically those said to prevent neurological diseases like Alzheimer's. Berries, olive oil, nuts, and dark, leafy greens are staples of the diet, based on large-scale studies of cognitive decline.

The plan is a hybrid version of the Mediterranean and DASH diets (both of which ranked higher), and focuses on the aspects of those two diets that have to do with the brain.

[Photo via @bluediamond]

7 of 11