A new study from Imperial has shown that the physical structure of food influences the hormones released as part of digestion.
These hormones include glucagon-like peptide-1 (GLP-1), GIP and PYY, as well as other post-meal responses like blood sugar, insulin and satiety hormones.
Researchers say the findings could potentially lead to ways to hack our diet – by designing or preparing food in certain ways to make us feel more full.
In the pilot study, researchers at Imperial College London and the Quadram Institute used chickpea meals prepared with contrasting cellular structures—intact cells versus broken cells—and measured various physiological responses in healthy human participants.
The findings revealed that meals with broken cell structures led to a rapid increase in blood glucose, insulin, and the gut hormone GIP. But intact cell structures resulted in a prolonged release of GLP-1 and PYY, promoting a greater sense of fullness.
This was because different hormones were released as the food components, or metabolites, reached different parts of the gastro-intestinal tract. GIP was released from higher parts of the tract, while GLP-1 was released from cells much lower down, or further on the food journey.
The study highlights the critical role of food structure in metabolism and its implications for understanding and combating diseases like obesity and type 2 diabetes.
Dr Mingzhu Cai, from 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 added: "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."
In the study, 10 adult participants resided as inpatients 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.
Over the following three mornings, participants were given one of three specially prepared test meals in a randomised order. After each meal, blood samples, intestinal content, and appetite scores (using visual analogue scales) were collected for up to three hours.
All test meals were made from freshly cooked chickpea porridge, flavoured with low-sugar blackcurrant jam and raspberry jelly2, and had identical nutrient content, but were processed differently resulting in different cellular structures. These structural variations included nutrients being either entrapped in cell clusters ('Intact-C'), within isolated single cells ('Intact-S'), or in a broken cell form ('Broken').
These structural differences were confirmed by light microscopy and were also shown to affect starch susceptibility to digestion in vitro, with the 'Broken' cell meal demonstrating the greatest release of starch digestion products.
Dr Cathrina Edwards of the Quadram Institute, said: "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".
Professor Gary Frost, Chair in Nutrition and Dietetics at Imperial College London, added: "Changing food structures could ultimately help to protect the population from communicable 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."
Upper-Gastrointestinal Tract Metabolite Profile Regulates Glycaemic and Satiety Responses to Meals with Contrasting Structure: A Pilot Study by Mingzhu Cai, Gary Frost et al is published in Nature Metabolism. DOI: 10.1038/s42255-025-01309-7
