Nuts are unique in their position among the healthiest foods. Though technically the “fruit” of the plant, nuts lack the high sugar and water content of most fruits. Instead, they’re dry and savory and have the high amounts of protein usually reserved for meat and dairy products. There are dozens of nut varieties (though the peanut is not one of them), each of which has a unique taste and appearance. So, what are the healthiest nuts?

1. Classifications of Nuts

Nuts vary in appearance, texture, and taste. They are classified by the type of covering they do–or do not–have.

Botanical nuts (or “true nuts”) are hard-shelled and do not split open to release seeds. Hazelnuts and chestnuts are popular botanicals.

Drupes have a fleshy covering over a pit or stone. Almonds, cashews, and walnuts are examples.

Gymnosperm seeds are naked and include pine nuts and ginkgo nuts.

Angiosperm seeds are part of a larger fruit and include Brazil nuts, Macadamias, and peanuts.