Researchers from the Quadram Institute in Norwich and Imperial College London showed that foods made with chickpea flour prepared in a way to keep the plant cells intact trigger a much healthier metabolic response during digestion than nutritionally identical foods made with conventional milled flour.

The findings show the importance of considering how processing affects the structure in assessing how healthy foods or diets are, and how preserving the natural structure is crucial in developing health-promoting ingredients.

Modern diets are behind a growing wave of obesity and diet-related conditions. Ultra-processed foods have recently become synonymous with this epidemic, but the term isn’t tightly defined and many of these foods are also high in known risk factors for diseases, like fats, sugars and salt.

What is often overlooked is the contribution “processing” itself plays on the microstructure of food, and how this affects digestion and the release of nutrients and sugars into the blood.

This is important as it changes how the body responds with signalling hormones, and pharmaceuticals that mimic these hormones have shown success for weight control and diabetes.

Could modern diets containing foods with more optimal structure for health also have similar effects?

To understand this, researchers from the Quadram Institute and Imperial College London designed porridge meals made from chickpeas that were nutritionally identical, apart from how the chickpeas themselves were processed.

In one porridge the chickpeas had been processed, breaking down the natural cellular structure, as happens when making conventional chickpea flour. In the other, a different process was used to ensure cells remain intact was used.

Previous studies in laboratory models of digestion have shown how preserving the intact cell structure protects the cells’ contents from attack by digestive enzymes, slowing down their breakdown and the release of sugars.

In humans, this would be expected to trigger the gut hormone feedback system to signal that the body is full and reduce appetite.

Model systems can’t recreate this feedback, but recent human studies have found that people eating intact whole cell chickpea flour products feel fuller for longer.

This new pilot study, published in the journal Nature Metabolism, provided direct evidence of this feedback mechanism in action.

Ten adult participants resided as in-patients for four days at the NIHR Imperial Clinical Research Facility. They were each fitted with two enteral feeding tubes to enable the collection of samples from their stomach and upper-small intestine- every 15 min over 180 min period- for measuring how food is digested and how it influences gut metabolites. Blood samples were collected in parallel to measure blood sugar, insulin, and gut hormones involved in regulating satiety. The ten healthy volunteers ate porridge meals made with either broken or intact cell chickpea flour.

The porridge made with the extensively processed “broken cell” chickpeas was digested more rapidly and increased the glucose peak in the participants’ blood two to four times more than porridge made with intact chickpea cells.

The porridge made with intact cells was digested more slowly and produced a prolonged release of the appetite-suppressing hormones GLP-1 and PYY. The participants also reported higher feelings of fullness.

“Although the foods in the study would have the same food label, because they contain the same ingredients and nutrient composition, we’ve shown how processing-induced changes to the structure leads to significant effects on hormone and blood sugar responses” said Dr Cathrina Edwards from the Quadram Institute, corresponding author.

Simple changes to processing that consider structure could deliver foods that consumers still enjoy, but which avoid some of the negative health effects associated with intensive processing.

First author, Dr Mingzhu Cai of Imperial College London’s Department of Metabolism, Digestion and Reproduction, explained: “The knowledge we’ve gained in understanding the release of metabolites in the gut will help us ultimately design food better so that it can have a greater impact on how full, or satisfied, we feel.”

She continued: “There’s a lot of discussion at present about GLP-1 agonists such as Ozempic. While natural levels of GLP-1 will never reach that level of pharmaceutical dose, by understanding how and where it is released, we have a better chance of increasing the doses that our bodies can produce.”

Professor Gary Frost, Chair in Nutrition and Dietetics at Imperial College London, added: “Changing food structures could ultimately help to protect the population from chronic diseases such as type two diabetes, and that’s why this research is so exciting. It’s all building up the knowledge in this area which will be essential for improving foods in the future.”

The study was supported by the Biotechnology and Biological Science Research Council, part of UKRI.

By using an alternative milling process, a unique, patent-protected flour, called PulseON, has been developed containing high proportions of intact cells. This is now being developed for commercial use by a spin-out company: PulseON Foods Ltd.

Reference: Upper-Gastrointestinal Tract Metabolite Profile Regulates Glycaemic and Satiety Responses to Meals with Contrasting Structure, Nature Metabolism DOI: https://www.nature.com/articles/s42255-025-01309-7