Researchers have confirmed that the stems and skins of fruits and vegetables frequently possess higher fibre content than the edible flesh.
Rachel Gibson and her colleagues at King’s College London analysed the fibre levels of 12 different produce types, including broccoli, kiwi fruit, watermelon, and bell pepper. The study revealed that in 10 of those 12 varieties, the components typically discarded by consumers contain more fibre than the parts usually eaten.
Butternut squash skin and seeds were found to contain 9.25 grams of fibre per 100 grams, while the flesh of the same vegetable contained only 2 grams per 100 grams. The core and skin of a pineapple were found to have 450 per cent more fibre than the fruit's flesh.
Christian Reynolds at City St George’s University of London described the research as an "exciting investigation". The average adult currently consumes approximately 15 grams of dietary fibre daily, yet only 4 per cent of British adults reach the recommended minimum of 30 grams.
Rachel Gibson said, "We’ve really got to shift our purchasing habits to buy whole fruits and vegetables, and then use all of the fruits and vegetables in dishes." The research team suggested that home cooks and caterers should start using squash peel, watermelon rind, and pepper stalks to increase public fibre intake.
Gibson noted that caterers could use these findings to create fibre-rich meals from produce that would otherwise be wasted.
The King’s College London canteen launched a "root to tip" menu in May 2025, which featured a West African peanut stew made with kale stalks, leek tops, and whole butternut squash. The menu also included a salad made with pickled watermelon rind.
Gibson stated that consuming a larger portion of harvested produce will also strengthen the resilience of the food system against climate shocks.
Gibson added, "Everything we pull out of the ground that we can eat, we should be eating."
