Fruit and Vegetable Scraps Contain More Fiber Than Flesh, King’s College London Finds
Most adults do not consume enough dietary fiber, and a significant amount of edible fiber is routinely discarded with fruit and vegetable peels, skins, and cores. New research from King’s College London suggests a simple solution: utilize more of the plant. Researchers found that “root-to-tip” eating – incorporating typically wasted parts of produce – could increase fiber intake and reduce food waste.
5x More Fiber in Pineapple Skin and Core
Pineapple skin and core contain 453.7% more fiber than the flesh of the fruit itself, according to the King’s College London study. Eating just the skin and core from one pineapple provides as much fiber as consuming five portions of the edible flesh. Butternut squash skin and seeds also proved to be a fiber powerhouse, containing 9.25 grams per 100 grams – nearly one-third of the UK’s recommended daily intake of 30 grams. Watermelon rind contains 2.10 grams of fiber per 100 grams, roughly equivalent to a slice of wholemeal bread.
UK Adults Fall Short of Fiber Goals
Only 4% of British adults meet the recommended daily intake of 30 grams of dietary fiber, consuming an average of just 16.4 grams per day, King’s College London reported. This shortfall occurs despite the well-known benefits of fiber for digestive health, reducing the risk of cardiovascular disease, type 2 diabetes, and certain cancers. Simultaneously, approximately 10 million tons of food is wasted annually in the UK, with fresh fruits and vegetables accounting for 36% of that waste.
Root-to-Tip Eating: A Sustainable Approach
Researchers examined whether increasing consumption of discarded plant parts could address both the fiber deficit and food waste issues. Dr. Rachel Gibson emphasized that the goal isn’t to eat large quantities of scraps, but rather to integrate them into everyday meals. King’s College London trialed a “root-to-tip” menu in its canteen in May 2025, featuring dishes like banana skin curry.
Concerns About Digestibility and Contaminants
While promising, the approach isn’t without caveats. A focus group at King’s College London identified “mental discomfort” about eating typically discarded parts and concerns about digestibility. The study noted potential concerns regarding pesticide residues, heavy metals, and naturally occurring toxic compounds.
Focus Group Feedback on Root-to-Tip Eating
Initial trials of the “root-to-tip” approach revealed barriers to consumer acceptance. Participants in a King’s College London focus group expressed concerns about digestibility and a lack of easily accessible nutritional information, particularly on social media. Despite these concerns, the trial showed that “root-to-tip” dishes made up a third of total daily hot menu sales at the university over a nine-week period.
Potential for Cost Savings and Improved Resilience
Integrating discarded parts into meals could also offer financial benefits, according to Dr. Gibson. “You’re effectively throwing away a substantial portion of what you’ve paid for,” she stated. Increasing the utilization of harvested fruits and vegetables could contribute to a more resilient food system in the face of climate change.
Fiber Content Varies by Produce Type
The research from King’s College London analyzed 12 common fruits and vegetables. Of these, 10 showed that the discarded parts contained more fiber than the parts typically consumed. Broccoli stalks, for example, contained fiber, although slightly less than the florets. The study’s findings are detailed in the International Journal of Food Sciences and Nutrition (DOI: 10.1080/09637486.2026.2734852).
FAQ
Is it safe to eat fruit and vegetable peels? Researchers acknowledge the need for further investigation into potential contaminants like pesticide residues and heavy metals.
How much more fiber are we talking about?
Butternut squash skin and seeds contain 9.25 grams of fiber per 100 grams, nearly one-third of the UK’s recommended daily intake. Pineapple skin and core contain 453.7% more fiber than the flesh, meaning five portions of the flesh would be needed to match the fiber content of the skin and core.
Are there any downsides to this approach?
Some individuals may experience digestive discomfort if they rapidly increase their fiber intake. The British Nutrition Foundation cautions against consuming tough stalks or seeds for young children.
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