Many people believe that the peels of fruits and vegetables possess special nutritional value, and now scientists have confirmed this. Researchers have found that these parts of the produce often contain significantly more fiber than the flesh we typically consume. The results of this new study were published in the International Journal of Food Sciences and Nutrition.
This discovery means that by discarding seeds, peels, and stems when preparing food, we are—unintentionally—getting rid of parts that are rich in fiber.
According to the researchers, both home cooks and professional chefs should adopt a “root-to-tip” approach to using produce. For instance, incorporating ingredients like pumpkin peels, watermelon rinds, or bell pepper stems into dishes can help increase dietary fiber intake.
“It is high time we changed our habits: buying whole fruits and vegetables and then using them in their entirety,” says Rachel Gibson of King’s College London.
Gibson and her colleagues analyzed the fiber content in 12 types of fruits and vegetables, including butternut squash, kiwi, watermelon, broccoli, and bell peppers. The scientists compared the amount of fiber found in the parts we usually eat with the parts that most often end up as waste.
It turned out that for 10 out of the 12 items studied, the parts typically discarded contained more fiber than the edible flesh. For instance, the seeds and peel of a butternut squash contain 9.25 grams of fiber per 100 grams, whereas the flesh contains only 2 grams. Similarly, the peel and core of a pineapple contain 450% more fiber than the flesh. While these parts can often be tough, researchers point out that they can be blended, grated, or roasted—processes that make them quite palatable.
Only 4% of adults in the UK consume the recommended daily intake of dietary fiber (30 grams); on average, an adult gets only about half that amount.
Rachel Gibson suggests that food service establishments could use these findings to create fiber-rich dishes by incorporating parts of produce that are typically discarded. According to her, this would not only reduce food waste and kitchen costs but also boost fiber consumption. In May 2025, a canteen at King’s College London launched a pilot “root-to-tip” menu. The offerings included a West African-style peanut stew made with squash, cabbage stalks, and leek tops, as well as a watermelon salad featuring pickled watermelon rind.
Gibson notes that consuming more of the fruits and vegetables we harvest would also make the food system more resilient to climate-related shocks. “Everything we take from the earth that is edible, we should eat.”
Christian Reynolds, from City St George’s, University of London, describes the research as “exciting.” But he notes that meat and dairy products are the most carbon-intensive food waste. Therefore, reducing fruit and vegetable waste is “part of the solution, but not the only thing we need to do,” he says.
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