Banana peels are a mainstay of slapstick comedy. Why? Danny DeVito says it's because "you have to give people permission to laugh. That's why they would always cut to the banana peel in the Laurel and Hardy movies."

It turns out that there are a lot more uses for fruit and vegetable peels than finding amusement in another person's minor mishap. They're loaded with phytonutrients that can keep you from slipping into poor health. (Wash the skins very well and use organic produce if you're eating the peel.)

Peach skin delivers almost twice the number of polyphenols as peach flesh — and a lot more fiber. A lab study showed that peach skin helps tamp down oxidative damage in the kidneys, liver, and brain. 

Eggplant skin (that is purple) contains a powerful antioxidant called nasunin, which tamps down inflammation, as well as flavonoids called anthocyanins that promote visual acuity. It addition, eggplant skin may protect against cancers and does protect cardiovascular health.

Apple peels are highly appealing for flavor and crunch — and nutrients. A raw apple with skin on contains up to 312% more vitamin K, 70% more vitamin A, 35% more calcium and potassium and 30% more vitamin C than a peeled apple. Skin a medium apple and you get about 2 grams of fiber; retain the peel and you'll get 4.4 grams.

Watermelon rind is edible raw, pickled, or sautéed, and contains the amino acid citrulline, which boosts libido, improves erectile dysfunction, and dilates blood vessels. The rind also contains fiber that eases digestion.