A new study by researchers at Arizona State University and their colleagues highlights a nutritional strategy for significant health improvement and weight management.
Participants who followed an intermittent fasting and protein-boosting regimen, where protein intake was evenly spaced throughout the day, saw better gut health, weight loss and metabolic responses. These benefits were significantly greater than those of simple calorie restriction.
The findings, reported today in the journal Nature communicationcould increase our understanding of the relationship between the gut microbiome and metabolism and improve obesity management strategies.
The researchers compared the effects of two low-calorie dietary interventions: a heart-healthy, continuous calorie-restricted diet (based on USDA nutritional recommendations) and a calorie-restricted regimen with intermittent fasting and protein stimulation.
The trial was conducted with 41 overweight or obese individuals over a period of eight weeks. Individuals in the intermittent fasting and protein boosting group showed a decrease in symptoms of gastrointestinal problems and an increase in the diversity of the gut microbiota compared to those in the calorie restriction group.
The intermittent fasting protocol increased beneficial microbes in the gut that have been linked to a lean body type and improved overall health. In addition, it increased the levels of certain proteins (cytokines) in the blood that are linked to weight loss, as well as amino acid byproducts that promote fat burning.
Intermittent fasting is an eating pattern that alternates between periods of fasting and eating. The method has recently become popular for its potential health benefits, including weight loss, improved metabolic health and improved brain function.
“Given the location of the gut microbiota and its constant interaction with the gastrointestinal tract, in recent years we have gained a deeper understanding of its critical role in nutritional responses,” said Alex Mohr, lead author of the new study. “Although limited in duration and sample size, this comprehensive study – which included analysis of the gut microbiome, cytokines, fecal short-chain fatty acids and blood metabolites – underlines the intricate interplay between diet, host metabolism and microbial communities.”
Mohr led the microbiome and molecular research, evaluating the microbial composition of the gut, inflammatory molecules called cytokines, SCFAs (metabolites derived from dietary fiber, important for regulating energy balance) and the metabolome.
Mohr is a researcher at the Biodesign Center for Health Through Microbiomes at ASU. Rosa Krajmalnik-Brown, director of the center, and researchers Devin Bowes, Karen Sweazea and Corrie Whisner are also contributing to the study.
Corresponding author Paul Anciero of the Department of Health and Human Physiological Sciences at Skidmore College led the clinical trial, which monitored weight loss and body composition.
The study also included contributions from ASU researchers Paniz Jasbi and Judith Klein-Seetharaman, from the School of Molecular Sciences, and Dorothy Sears and Haiwei Gu, from the College of Health Solutions.
Diet, microbiome and weight loss
The gut microbiome refers to the diverse community of microorganisms residing in the gastrointestinal tract, including bacteria, viruses, fungi, and other microbes. This complex ecosystem contains many trillions of organisms and plays a crucial role in essential bodily functions and overall health.
The gut microbiome helps break down food, produce vitamins and promote nutrient absorption. It plays a role in the development and function of the immune system by protecting the body against harmful pathogens. Finally, the gut microbiome sharply regulates metabolism, which influences body weight, fat storage, and insulin sensitivity.
Calorie restriction, intermittent fasting (limiting food consumption to certain times on certain days), and protein stimulation (controlled protein intake at specific meals) have been shown to influence body weight and composition, but the effect of these dietary modifications on the gut microbiome has been demonstrated to date unclear at the time.
“A healthy gut microbiome is essential for overall health, especially in managing obesity and metabolic diseases,” said Sweazea, the ASU principal investigator of this Isagenix-funded study. “The gut bacteria influence the way 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, underscoring the critical role of gut health in preventing and managing metabolic disorders.”
Study and findings
The clinical trial involved 27 female and 14 male participants who were overweight or obese. The participants were divided into two groups: one followed the intermittent fasting and protein stimulation regimen, and the other followed a heart-healthy, calorie-restricted diet. Both groups were monitored for eight weeks for changes in weight, body composition, gut microbiome composition and plasma metabolomic characteristics.
Participants who followed the intermittent fasting and protein stimulation regimen experienced a significant reduction in gut symptoms and an increase in beneficial gut bacteria, especially from the Christensenellaceae family. The study also found that these microbes are associated with improved fat oxidation and metabolic health. In contrast, the calorie-restricted group showed an increase in metabolites linked to longevity-related pathways.
Despite both groups having similar average weekly energy intake, the intermittent fasting and protein stimulation group achieved greater weight loss and fat reduction with an average loss of 8.81% of their initial body weight during the study. In comparison, those who followed a calorie-restricted diet lost an average of 5.4% body weight.
Participants who followed the intermittent fasting and protein stimulation diet experienced a reduction in total body fat, including abdominal fat and deep abdominal fat, and saw an increase in percentage of lean body mass.
The study underlines the potential of intermittent fasting and high-protein diets in improving gut health and weight management. Although further research is needed, these findings provide a promising opportunity for creating effective nutritional interventions for obesity and related metabolic disorders.
“By identifying shifts in specific microbes, functional pathways, and associated metabolites, this work holds promise for personalized health strategies as we can better tailor nutritional regimens to improve gut function and metabolic outcomes,” says Mohr.
Other institutions contributing to the research: Systems Precision Engineering and Advanced Research (SPEAR); Center for Translational Sciences, Florida International University; Isagenix International LLC; and the School of Health and Rehabilitation Sciences, Department of Sports Medicine and Nutrition, University of Pittsburgh.
