Eating 'Root-to-Tip': Increasing fibre intake, reducing food waste

In August 2024, the ‘Root-to-Tip’ project was one of nine new projects awarded funding in the first round of the One King’s Impact Fund. Led by Dr Rachel Gibson, Senior Lecturer in Nutrition & Dietetics in the Department of Nutritional Sciences, the ‘Root-to-Tip’ project aims to increase fibre intake and reduce food waste in the UK population by using more parts of the plant (i.e. peels and stalks) in recipes.

To do this, the team is using a ‘Living Laboratory’ approach to conduct research across King’s Food venues through the launch of new Root-to-Tip dishes that use more of the plant.

What is dietary fibre?

Dietary fibre is a term used to describe certain carbohydrates found naturally in the plants that we eat. Unlike carbohydrates like sugars and starches that are digested in the small intestine, fibre stays intact until it reaches the large intestine where it is broken down by gut bacteria.

Eating a diet rich in fibre is associated with a lower risk of heart disease, stroke, type 2 diabetes and bowel cancer, however most adults in the UK aren’t meeting the recommended intake of at least 30g of fibre per day¹.

Fibre is mainly found in plant-based foods, including fruits, vegetables, wholegrains and legumes. As fibre tends to be more concentrated in the outer layers of fruits and vegetables (e.g., peels and rinds), the project team hypothesised that eating more of the plant could therefore offer a way to increase fibre intake, while helping to reduce the amount of edible fruit and vegetables that are thrown away. 9.5 million tonnes of food is wasted in the UK each year², and fruit and vegetables account for 35% of edible food waste³.

To develop the new dishes, the team started by identifying suitable fruits and vegetables for Root-to-Tip dining. Under the leadership of King’s Food Executive Chef Graeme Collie, chefs from King’s Food then developed and tested new recipes incorporating the parts of the plants that would usually be thrown away.

There is limited data on the nutritional content of the parts of plants that we don’t usually eat. As part of the project, the researchers in the Department of Nutritional Sciences have measured the amount of dietary fibre in the rinds, stalks and peels of twelve fruits and vegetables that have been used in the new King’s Food dishes. Initial results show that swapping out ‘flesh’ for traditionally discarded parts of plants, such as butternut squash peel, can increase the dietary fibre in a meal by up to 15%.

Putting the ‘Root-to-Tip’ concept to the test

The King’s Food Spring menu offering features 29 unique Root-to-Tip recipes available to staff and students at King’s from now until September.

Over the next couple of months, the team will evaluate sales and acceptability of Root-to-Tip dining within King’s Food. They will survey staff and students to understand what drove them to purchase the Root-to-Tip dishes, their perceptions of Root-to-Tip dining, and plate waste from the Root-to-Tip dishes versus the standard King’s Food dishes.

If the project is successful within King’s Food, the team plans to scale up their plans by securing external funding to test Root-to-Tip dining in other UK universities, as well as in home and retail settings.

“It’s really challenging to change what people eat, particularly at a population level,” adds Dr Gibson. “If we can demonstrate from this project that we can reduce food waste in a way that improves fibre intake and that is acceptable to consumers, we hope that root-to-tip dining could be a low-cost way to work towards higher fibre intakes, improved population health and reduced food waste in the UK.”

References

1. The British Dietetic Association (2021), Fibre. Available at  https://www.bda.uk.com/resource/fibre.html (accessed 1 May 2025).
2. Waste Managed (2025), Food Waste – 2025 Facts & Statistics. Available at https://www.wastemanaged.co.uk/our-news/food-waste/food-waste-facts-statistics/ (accessed 1 May 2025).
3. WRAP (2023), UK Food Waste & Food Surplus – Key Facts. Available at https://www.wrap.ngo/sites/default/files/2024-01/WRAP-Food-Surplus-and-Waste-in-the-UK-Key-Facts%20November-2023.pdf (accessed 1 May 2025).