Guava is an obscure tropical fruit that's subtly acidic, with sweetness that intensifies as you eat your way to the center. Why it's healthy: Guava has a higher concentration of lycopene -- an antioxidant that fights prostate cancer -- than any other plant food, including tomatoes and watermelon. In addition, 1 cup of the stuff provides 688 milligrams of potassium, which is 63 percent more than you'll find in a medium banana. And guava may be the ultimate high-fiber food: There's almost 9 grams of fiber in every cup.
How to eat it: Down the entire fruit, from the rind to the seeds. It's all edible -- and nutritious. The rind alone has more vitamin C than you'd find in the flesh of an orange. You can buy guava in the produce section of higher-end supermarkets or in Latin grocery stores or Guava nectar is widely available in the juice section at most stores.