There’s no need to throw away all peelings and offcuts.
Eat the skin. Wash and eat apples, pears, peaches, with their skin. Scrub rather than peel the root vegs with a vegetable brush (carrots, potatoes, parsnips, …), especially if you cook them. The highest concentration of nutrients tends to be in and under the skin. And the roasted skin of potatoes is just delicious!
Cook the stalks and leaves. For instance, the stalks and leaves in cauliflowers and broccolis can be used as the florets, even the thick ones (just chop in small pieces). Often the stalks of herbs have a much stronger flavour than the leaves so chop them finely and use them in your dishes. In Thai recipes, the roots and stalks of coriander are often finely chopped and used in the paste, and the leaves are used to finish the dish, like in this Thai green curry paste.
Use citrus peel. Make marmalade, or candied citrus peel recipe, or just dry them and use to flavour all sorts of things, from olive oil and tea to cakes and sugar (allow to dry in the open air on a rack or towel, about three or four days for twists, less for zest; and once dry, store in a clean jar)
Make crisps. Potato and apple peels make a fantastic, crispy snack. Pre-heat your oven to 400 degrees, arrange the peels on a sheet pan, and spray lightly with oil (canola, olive, coconut). Then sprinkle with whatever seasonings you prefer. For potatoes, a combination of salt, pepper, cajun seasoning, or herbs can be delicious. For apples, sugar and cinnamon are fantastic. Place in oven for 10 minutes, stirring around halfway through cook time. No waste, and you get all the nutrients from the skins!
Vegetable Stock. Homemade vegetable stock is easy and far tastier than the cartons from the store. Save up your veggie ends and peelings (potato peels, onion skins, carrot peels, leek ends, fresh herb stems, ect.) in the freezer in a specified container. When full, take it out and boil them together in water for a few hours, or put in a slow cooker and let it do the work. Strain at the end and you’ve got stock!
Add depth of flavor. Cheese rinds almost always get tossed, as they’re too tough to eat. However, they still have a ton of flavor to give if tossed in with stock or braised with tougher greens such as chard or cabbage. Just be sure to remove any wax coating beforehand. Rinds can also be stored in the freezer until ready to use.
It is highly advisable if you are eating veggie skins, tops and other scraps to be sure to buy organic, and local if possible.