The skinny on vegetable skins (Dr. Roizen)

Skinny latte (nonfat milk), skinny jeans (too tight to sit in), skins on the golf course (betting on every hole): The words “skinny” and “skin” get used in a lot of ways. But skins on vegetables — too often they’re just thrown away, even though they’re loaded with healthy nutrients. Around a third of the fiber in a vegetable is in its skin, and inflammation-fighting polyphenols in a fruit’s peel can be 328 times greater than in the pulp.

Apple skins contain far more nutrients than the pale flesh inside. A small, raw apple with skin contains about 3.6 milligrams fiber, 159 milligrams potassium and 8.9 milligrams calcium. Peel it and you get around 1.7 milligrams of fiber, 119 milligrams of potassium and 6.6 milligrams calcium. Three ounces of boiled potatoes without skin — 7.4 milligrams vitamin C; leave the skin on and you get 9.1 milligrams.

What about cucumbers, the scruffy outside of carrots or watermelon rind? The peel and seeds of cucumber are the most nutrient-packed components. About 40% of phytonutrients in carrots are in the outer skin, according to Tufts Antioxidant Research laboratory. Watermelon rind delivers more fiber and potassium than the fleshy part and contains the amino acid citrulline, important for creating another amino acid, arginine, that promotes heart health and strengthens your immune system (and orgasms).

So don’t skin everything — and if you’re concerned about pesticide residue, go organic. Not into organic? Wash skins well and scrub rough outer peels. About 40% of pesticides are removed by washing and twice that through peeling (a reason to go organic).