Most of the time, eating healthier requires a little more work—like cooking your meals at home and diligently inspecting food labels. So this healthy hack will come as a welcome change: Put down the peeler and stop removing the edible skins from your fruits and vegetables.

The colorful peels on the outsides of your produce are often the most concentrated source of vitamins, minerals, and antioxidants. 

Now, this doesn’t mean that all the nutrients are located in the peels alone; experts point out that when you peel a tomato, for example, you won’t lose much of its beneficial lycopene. But there are some peels that offer a unique benefit independent of the fruit or vegetable flesh.

Here are the six you should know about. 

1. Apples

Peeling an apple won’t really rob you of a whole lot of vitamin C, but you will lose out on pectin—a soluble fiber that can help keep you regular and lower your “bad” LDL cholesterol and blood sugar.

Try these awesome Paleo Bacon-Apple Pies For One. Pectin also slows digestion—helping to keep cravings at bay.

2. Carrots

Carrots are rich in polyacetylenes—a chemical compound currently being researched for its potential to kill human cancer cells in test tubes. They may have antifungal, antibacterial, and anti-inflammatory effects, too. \

But these compounds are concentrated just below the skin—so either leave your carrot skins on or go easy with the peeler and remove only a thin strip.

Different varieties of carrots have even more healthy perks. One of the Surprising Health Benefits Of Purple Carrots is that they are rich in anthocyanins—the antioxidant compound that gives blueberries their distinctive color and superfood status.

3. Potatoes

Gram for gram, potato skins have more fiber, iron, and folate than potato flesh. When planting potatoes, choose deeply pigmented purple potatoes and the skin becomes even more important.

Researchers at the University of Maine say the skins of these potatoes contain 5 to 10 times more antioxidants than the flesh.

Related: What Happens When You Stop Eating Fruits and Vegetables?

4. Cucumbers

Peeled cukes have less calcium, magnesium, phosphorous, potassium, vitamin A, and vitamin K than their fully intact counterparts. Plus, nearly all of cucumber’s fiber comes from the peel—the inner flesh is mostly water.

5. Eggplant

Eggplant skin is packed with an antioxidant called nasunin. The compound hasn’t been extensively researched on its own, but one animal study found in the U.S. National Library of Medicine and National Institutes of Health suggests that it could be important in maintaining healthy brain tissue.

Plus, nasunin is part of a larger family of antioxidants known as flavonoids. The more flavonoids you eat, the less likely you are to gain weight over time.

6. Grapes

Although grapes are one of The Worst Summer Fruits because more pesticides are used on grapes than any other fruit, don’t cut them out—or their skin off—just yet.

The skins are where you’ll find all of red grapes’ resveratrol—the phytochemical that seems to benefit heart and brain health and that’s been shown to slow cancer growth in cell and animal studies.

The article 6 Fruits + Veggies You Should Never Peel originally ran on Prevention.com.