A healthy diet is rich in fruits, vegetables, fiber, lean protein and "good" monounsaturated and polyunsaturated fats in moderation.

What's more, participants' whose diets were highest in polyunsaturated fats from fish as well vegetable oils reduced their risk for dementia.

Unsaturated fats such as mono-and polyunsaturated fats should be the headline here, as they support satiety, boost cognitive function and promote cardiovascular health.