Walnuts

On Eat This, Not That's list of 8 Foods You Should Eat Everyday. Walnuts are richer in heart-healthy omega-3s than salmon, loaded with more anti-inflammatory polyphenols than red wine, and packing half as much muscle-building protein as chicken. Other nuts combine only one or two of these features, but not all three. A serving of walnuts is about one ounce or seven nuts is a good postworkout recovery snack.
Substitutes - Almonds, peanuts, pistachios, macadamia nuts, hazelnuts.
Fit it in - Sprinkle on top of salads, pancake batter, fish or chicken marinade topping.

Source: Eat This, Not That