Spinach

Calorie for calorie, leafy green vegetables like spinach with its delicate texture and jade green color provide more nutrients than any other food. Although spinach is available throughout the year, its season runs from March through May and from September through October when it is the freshest, has the best flavor, and is most readily available. Spinach has the bitterness of beet greens and the slightly salty flavor of Swiss chard that makes them delicious as a soup basis or filing to a pie.