Citrus peel
“Rather than throwing away that lemon, orange, or even grapefruit peel, I use every piece of it as a zest for marinades, homemade salad dressings, and baked goods!” says Angie Asche, MS, RD, a sports dietitian in Lincoln, NE. “Citrus peels contain vitamin C and fiber, making them both a flavorful and nutritious food scrap.”