Everything we eat turns into glucose—the gasoline that keeps our bodies running—but each food’s conversion rate is different. Think of carbs as the hare that runs out of steam before the finish line, while protein and fiber deliver a slow and steady stream. Equal amounts of beans and lentils give you the endurance of a marathoner, even if you can’t huff your way around the block. Perk up with a serving of rice and beans, low-fat chili, edamame or hummus with pita.

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