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If you like sweet potatoes, try butternut squash.

Why it's so good for you
Both are excellent sources of vitamins A and C, nutrients that keep your immune system in cold- and flu-fighting shape, says Babb, author of Anti-Inflammatory Eating for a Happy, Healthy Brain. But squash has less than half the calories.

How to enjoy
Roasting gives squash a caramelized sweetness, says registered dietitian and chef Jessica Swift. Cube and toss with oil, then roast at 400 degrees for 30 minutes. Mix with pomegranate seeds, chopped scallion, lemon zest, crushed pistachios and a drizzle of balsamic vinegar.