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Spinach

Good for: Energy

These tasty leaves are a great source of iron (especially if you don't eat meat), which is a key component in red blood cells that fuel our muscles with oxygen for energy.

Researchers in Sweden recently identified another way in which these greens might keep you charged: Compounds found in spinach actually increase the efficiency of our mitochondria, the energy-producing factories inside our cells. That means eating a cup of cooked spinach a day may give you more lasting power on the elliptical machine (or in your daily sprint to catch the bus).

Try this recipe: Asian Spinach Salad

Next: Artichokes