For most of us, a vegetable peeler is an essential kitchen tool. And while it’s definitely handy at times (looking at you, mangos!), do we ever stop to consider how often we actually need to use it? Or how much time, energy, and valuable nutrition we’re wasting when we strip off a vegetable's outer layer of organic goodness and toss it in the trash?

According to Dr. Amy Lee, Head of Nutrition for Nucific, the skins of many of these fruits and vegetables actually contain valuable fiber, antioxidants, and other vitamins: irreplaceable nutritional resources that we often completely ignore. Here are five fruits and vegetables you should keep away from your peeler.

1. Potatoes

Whether we’re peeling them for our favorite Thanksgiving side or roasting them whole for twice-baked potatoes, the skins of our spuds are often destined for the garbage. But according to Dr. Lee, these same skins can contain “significant amounts of potassium” along with “lots of fiber.” Discarding the skins wastes approximately half of the dietary fiber that the potato has to offer, along with 25 percent of its potassium. Plus, a ton of time messing around with a slippery potato and your peeler. Loaded potato skins, anyone?

2. Eggplant

Italian nonna wisdom would have us believe that those purple skins are bitter and tough, but when was the last time you ate a slice of eggplant parm and thought “wow, these skins are really dragging this down?” The reality is that the eggplant’s skin often helps to keep the slices intact as the interior cooks and softens, making dishes like eggplant cutlets and eggplant manicotti possible. Additionally, according to Dr. Lee, the skin also contains an anthocyanin called nasunin that's a valuable nutrient that helps to protect brain cells and facilitate blood flow to the brain.

3. Apples

Whether or not you used to eat packaged peeled apple slices in preschool, those days are long gone. While it’s true that the interior of the apple contains a ton of valuable nutrients, including vitamins A and C, potassium, and calcium, the peels contain significantly larger quantities and in more concentrated levels. Peeling is not only a waste of time, but a big waste of nutrients. And even if you absolutely must peel your apples (perhaps because you’re parenting a child who absolutely refuses to eat apples with the skins on?), don’t throw them away! Toss those peels with a little cinnamon sugar and throw them in the oven for a batch of “skin-ny” apple chips.

4. Peaches and Kiwi

The fuzz on these fruits might be a deal-breaker for some, but according to Dr. Lee, that fuzzy skin is loaded with fiber and vitamins that can have a big impact on our digestive health and immunity. Kiwi skin, according to Dr. Lee, is particularly high in Vitamin E, a key antioxidant that promotes immunity. Now, if you’re picky about texture, chances are you don’t care how many valuable nutrients are buried in the fuzz. But before you chuck the entire idea into the trash (along with the peels), just stop and consider: Do you really notice that texture when it’s been cooked down in a peach cobbler? Or when it’s been chopped up into bite-sized pieces and mixed into a salsa? There might be some cases where you can leave the peeler behind.

5. Citrus

Okay, so you usually have to peel citrus fruits, but you should definitely think twice before just throwing out the peels. While they can’t be eaten raw, lemon, lime, and orange peels are great for rubbing into sugar, infusing into simple syrup or—as the holidays approach— candying to make your own homemade fruitcake or mince pies. When all else fails, save peels for your 6 o’clock negroni or old fashioned and boast to your friends about the new-found health benefits of your cocktail hour, brought to you courtesy of your antioxidant-rich cocktail garnishes.

A few last words...

If you (like me) are inspired to embark on a skin-eating crusade—sounds weird, but just go with it—there are a couple of things to keep in mind. Dr. Lee advises that if you’re prone to digestive issues, it’s smart to be aware and introduce extra fiber slowly. Also, make sure you’re watching out for cleanliness. “Wash your fruits [and vegetable] thoroughly before consumption,” Dr. Lee recommends, reminding us that “pesticides or chemicals” sprayed onto the produce may leave “residue on the skin.” Citrus fruits are sometimes even waxed—and you don’t want to be eating that!