Intermittent Fasting For Gut Health And Weight Management

The researchers set out to advance the understanding of the relationship between the gut microbiome and metabolism and improved strategies for managing obesity by comparing the effects of 2 calorie dietary interventions: a heart-healthy continuous calorie-restricted diet (based on USDA recommendations), and a calorie-restricted regimen incorporating intermittent fasting and protein pacing (involving evenly spaced protein intake throughout the day).

Intermittent fasting eating patterns cycle between periods of eating and fasting. These methods are gaining popularity for their potential health benefits including weight loss, enhanced brain function, and improved metabolic health. These protocols have been shown to also increase the population of beneficial gut microbes and levels of certain proteins in the blood that are linked to a lean body type, fat burning, and overall improved health. 

The gut microbiome is a diverse community of microorganisms in the gastrointestinal tract that plays crucial roles in essential bodily functions and overall health such as helping to break down food, producing vitamins, and promoting absorption of minerals. It also has important roles in the development and function of the immune system, and regulating metabolism that impacts body weight, fat storage, and insulin sensitivity. 

"Given the gut microbiota's location and its constant interaction with the GI tract, we have been gaining a deeper understanding of its pivotal role in dietary responses these last several years," says Alex Mohr, lead author of the new study and a researcher with the Biodesign Center for Health Through Microbiomes at ASU. "While limited in duration and sample size, this comprehensive investigation -- which included the analysis of the gut microbiome, cytokines, fecal short-chain fatty acids, and blood metabolites -- underscores the intricate interplay between diet, host metabolism, and microbial communities."

"A healthy gut microbiome is essential for overall health, particularly in managing obesity and metabolic diseases," says Sweazea, the ASU principal investigator of this Isagenix-funded study, who is also a researcher with the Biodesign Center for Health Through Microbiomes at ASU. "The 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, underscoring the critical role of gut health in preventing and managing metabolic disorders."

This study involved 41 participants who were overweight or obese who were placed in one of the 2 dietary intervention groups over a period of 8 weeks. The participants were monitored for changes in body weight, body composition, gut microbiome composition, and plasma metabolomic signatures. According to the researchers, those in the intermittent fasting and protein-pacing group showed a decrease in symptoms of gastrointestinal problems and an increase in diversity of the gut microbiota compared with those in the calorie-restriction group.

Those in the intermittent fasting and protein pacing group had an increase in beneficial gut bacteria, particularly from the Christensenellaceae family, which were found to be associated with improved fat oxidation and metabolic health. In comparison, those in the calorie-restricted group experienced increases in metabolites linked to longevity-related pathways. 

While both groups had similar average weekly energy intake, those in the intermittent fasting and protein pacing group experienced greater weight loss and fat reduction with an average loss of 8% compared to those in the calorie-restricted group’s average loss of 5.4% body weight. 

Additionally, those in the intermittent fasting and protein pacing group experienced reductions in overall body fat, which includes belly fat as well as deep abdominal (visceral) fat, and they also saw an increase in their percentage of lean body mass. 

"By identifying shifts in specific microbes, functional pathways, and associated metabolites, this line of work holds promise for personalized health strategies as we can better tailor nutritional regimens to enhance gut function and metabolic outcomes," Mohr says.

While additional research is required, these findings highlight the potential of intermittent fasting and protein pacing in improving gut health and weight management as a promising path for creating effective dietary interventions to tackle the obesity epidemic and the related metabolic disorders.