Ozempic – known generically as semaglutide – has taken the weight-loss market by storm, promising to help people shed pounds quickly. Though many use the drug to reduce body weight, it is mostly prescribed for treating type 2 diabetes in adults and carries a high price without insurance coverage. But what if you could achieve weight loss and improved glucose control without medication?

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New research led by Frank Duca, associate professor in the University of Arizona Department of Animal and Comparative Biomedical Sciences in the College of Agriculture, Life and Environmental Sciences, suggests that consuming foods rich in beta-glucan, a type of fiber found in oats and barley, can reduce body weight and obesity. The study, published in The Journal of Nutrition, analyzed the impact of different fibers on gut microbiota – the community of tiny microbes living in the digestive system that are responsible for breaking down the food we eat.

"We know that fiber is important and beneficial; the problem is that there are so many different types of fiber," Duca said. "We wanted to know what kind of fiber would be most beneficial for weight loss and improvements in glucose homeostasis so that we can inform the community, the consumer and then also inform the agricultural industry."

Not all fiber is created equal

The researchers looked at the effect of five different plant-based fibers in rodent diets: pectin, beta-glucan, wheat dextrin, starch and cellulose. Only beta-glucan resulted in reduction of body weight and fat, as well as improvements in glucose homeostasis. Beta-glucan is a unique fiber that is found in many foods, including oats, barley, mushrooms and yeasts, and future studies will examine how different sources of beta-glucan could differ in their effectiveness.

Changes in metabolites – the molecules produced when gut bacteria interact with fiber – seemed to be responsible for the weight-loss effects,  particularly a specific metabolite called butyrate. Butyrate is a key fuel source for colon cells, promoting a healthy gut barrier to reduce systemic inflammation. Butyrate also induces the release of gut peptides, or messengers that regulate the functions of the gut, such as the glucagon-like peptide-1, or GLP-1.

Drugs like semaglutide are synthetic versions of GLP-1, which stimulate insulin and can also help people feel full. One key difference of naturally occurring GLP-1 is its rapid degradation near the intestine, whereas semaglutide is made to last longer and target the brain.

"Part of the benefits of consuming dietary fiber is through the release of GLP-1 and other gut peptides that regulate appetite and body weight," Duca said. "However, we don't think that's all of the effect. We think that there are other beneficial things that butyrate could be doing that are not gut peptide related, such as improving gut barrier health and targeting peripheral organs like the liver."

Duca is researching other types of fiber that can be beneficial for weight reduction. In a previous study, the Duca Lab discovered that barley flour was the most effective in promoting weight loss compared to several other commercially available flours. Other studies involving oligofructose have also demonstrated beneficial effects. In the future, Duca hopes to collaborate with other researchers to develop enhanced fibers that can optimize the release of butyrate.