Why You Should Eat Food Scraps, According to Dr. Li

Americans throw away 30 percent of the food we buy. That's bad for the planet—and those tossaway bits have major health benefits, too. Dr. William Li, author of 'Eat to Beat Disease' and Rach's fave health guru, shows how the food you toss could save your life.
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vitamin and supplement jar

“Mother Nature produces a food pharmacy—or, as I like to call it, a food farm-acy,” says Dr. William Li, a Harvard-educated physician and New York Times best-selling author. “Eating more fruits and vegetables can reduce the risk of chronic diseases such as diabetes, obesity, stroke, and cancer.” But it’s not just eating more fruit and veg that matters, he says—it’s eating all of the fruit and veg. 

“If you’ve ever bought broccoli from the farmers’ market, you’ve realized the florets are a small part of the vegetable, that it’s mostly made up of a long stalk. But when we buy broccoli and bring it back to our kitchens, what do we do? We cut off the stalks and throw them away,” says Li. “We’re now discovering that some of the produce parts we often trash might actually be useful for our health. That means you can be more sustainable with your food, and your body will thank you.” 

Fruits and vegetables contain natural chemicals called bioactives, which activate our health defenses, explains Li. For example, broccoli has sulforaphane and carrots have carotenoids. These substances not only help the foods taste better and give them their color, but research has shown they also can cut off the blood supply to bad blood vessels that might lead to cancer. “My co-researchers and I wanted to prove that, so we tested the different food parts,” says Li. “We found that the parts we throw away—the broccoli stalks and carrot greens—have twice the cancer-starving activity as the broccoli florets and the carrot taproots.” More research is needed, says Li, but “this is building the evidence that there’s something powerful in what we’re not eating that can contribute to our health and help our bodies fight off disease.” 

apple peeling

A similar pattern can be found with apples. “People peel them and throw the cores away, but that apple peel contains a chemical called ursolic acid that helps to improve circulation by growing healthy blood vessels,” says Li. It’s the case with mushrooms, too: “We tend to cook with the caps, and the stipes wind up in the trash. Mushrooms have beta-glucan, which helps to activate our immune systems, and while it’s present in the cap, in a 2016 study, researchers found more beta-glucan in the stipes than in the caps for most of the mushrooms they analyzed, including shiitake and white button.” 

Moral of the story? “We should move from the traditional idea that healthy eating is about what you cut out and make healthy eating about what we add in,” says Li. “Let’s reduce food waste and be healthier at the same time.”

Four Tasty Ways To Repurpose Food Scraps

1. Puree broccoli stalks and mushroom stipes in a blender and use them in a soup.

2. Take your favorite pesto recipe and swap out the basil for carrot greens. 

3. Stir-fry broccoli stalks and mushroom stipes along with other veg for a weekday wok.

4. Bake apple peels at 400° for 15 minutes. Sprinkle with cinnamon and sugar. 

This article originally appeared in our Summer 2020 issue. Get the magazine here