Intermittent fasting promises improved gut health and weight control

A new study by Arizona State University researchers and colleagues highlights a dietary strategy for significantly improving health and weight control.

Participants who followed an intermittent fasting and protein feeding regimen, which involves consuming protein evenly throughout the day, demonstrated better gut health, weight loss, and improved metabolic parameters. These benefits were significantly greater than those seen with calorie restriction alone.

The findings, published in the journal Nature Communications, could expand our understanding of the links between the gut microbiome and metabolism, and improve strategies to combat obesity.

The researchers compared the effects of two low-calorie dietary interventions: a heart-healthy continuous calorie-restricted diet ( based on USDA recommendations ) and a calorie-restricted regimen that included intermittent fasting and protein feeding.

The trial involved 41 overweight or obese people over eight weeks. Those in the intermittent fasting and protein diet group showed reduced gastrointestinal symptoms and increased gut microbiota diversity compared to the calorie restriction group.

Intermittent fasting increased the number of beneficial microbes in the gut, which are associated with a leaner physique and better overall health. It also increased levels of certain proteins (cytokines) in the blood that are associated with weight loss, as well as amino acid metabolites that promote fat burning.

Intermittent fasting is an eating pattern that alternates periods of fasting and eating. The method has recently become popular due to its potential health benefits, including weight loss, improved metabolic health, and improved brain function.

“Given the location of the gut microbiota and its constant interactions with the GI tract, we have gained a deeper understanding of its key role in dietary responses in recent years,” says Alex Moer, lead author of the new study.

"While the study is limited in time and sample size, this comprehensive study—which included analysis of the gut microbiome, cytokines, faecal short-chain fatty acids, and blood metabolites—highlights the complex interactions between diet, host metabolism, and microbial communities."

Moher led microbiome and molecular research evaluating the composition of gut microbes, inflammatory molecules called cytokines, short-chain fatty acids (SCFAs), and the metabolome.

Moher is a researcher at the Center for Microbiome Health at Arizona State University. Center Director Rosa Krajmalnik-Brown and researchers Devin Bowes, Karen Sveazeya and Corrie Wisner also contributed to the study.

Co-author Paul Anciero of the Department of Physiology and Health Physiology at Skidmore College led the clinical trial, which tracked weight loss and body composition.

The study also included contributions from Arizona State University researchers Paniza Jasby and Judith Klein-Seetharman of the School of Molecular Sciences, and Dorothy Sears and Haiwei Gu of the College of Health Solutions.

Intermittent fasting has been shown to have a positive effect on the gut microbiome, promoting the growth of beneficial bacteria, which may improve overall digestive health. New research shows the benefits of a protein-rich intermittent fasting diet for weight management.

The Digestive System, Microbiome, and Weight Loss

The gut microbiome is the diverse community of microorganisms that live in the gastrointestinal tract, including bacteria, viruses, fungi, and other microbes. These complex ecosystems play an important role in vital body functions and overall health.

The gut microbiome helps break down food, produce vitamins, and facilitate nutrient absorption. It plays a role in the development and function of the immune system, protecting the body from harmful pathogens. Finally, the gut microbiome actively regulates metabolism, influencing body weight, fat storage, and insulin sensitivity.

Calorie restriction, intermittent fasting (restricting food intake to specific time windows), and protein feeding (controlled protein intake during specific meals) have all been shown to impact body weight and body composition, but the impact of these dietary changes on the gut microbiome has remained unclear.

The human gut contains trillions of bacteria and other microbes that together form the gut microbiome. New research is exploring how these diverse microorganisms help regulate weight. Researchers at Arizona State University are studying the effects of an intermittent fasting diet combined with protein distribution on body weight and overall health. Source: Arizona State University Biodesign Institute.

“A healthy gut microbiome is essential for overall health, especially in managing obesity and metabolic diseases,” says Sveazeya, the principal investigator at Arizona State University.

“Gut bacteria influence how we store fat, balance glucose levels, and respond to hormones that make us feel hungry or full. Disruptions in the gut microbiota can lead to increased inflammation, insulin resistance, and weight gain, highlighting the critical role of gut health in preventing and managing metabolic disorders.”

Research and results

The clinical trial included 27 women and 14 men who were overweight or obese. Participants were divided into two groups: one followed an intermittent fasting and protein-rich diet, and the other followed a heart-healthy calorie-restricted diet. Both groups were followed for eight weeks to measure changes in body weight, body composition, gut microbiome composition, and plasma metabolic parameters.

Participants who followed the intermittent fasting and protein-based diet experienced significant reductions in gut symptoms and increases in beneficial bacteria in their gut, particularly those from the Christensenellaceae family. The study also found that these microbes were associated with improved fat oxidation and metabolic health. In contrast, the calorie-restricted group showed increases in metabolites associated with pathways linked to longevity.

Although both groups had similar average weekly energy intake, the intermittent fasting and protein feeding group achieved greater weight loss and fat loss, losing an average of 8.81% of their starting body weight over the course of the study. In comparison, those on the calorie-restricted diet lost an average of 5.4% of their body weight.

Participants following the intermittent fasting and protein diet experienced a decrease in overall body fat, including belly fat and deep abdominal fat, and an increase in the percentage of muscle mass.

The study highlights the potential of intermittent fasting and protein-based diets to improve gut health and weight management. Although further research is needed, these findings offer a promising avenue for developing effective dietary interventions to combat obesity and related metabolic disorders.

“By identifying changes in specific microbes, functional pathways, and associated metabolites, this line of research offers promise for personalized health strategies as we can better tailor dietary regimens to improve gut function and metabolic outcomes,” says Moher.