A recent study published in Nature Communications has revealed that intermittent fasting combined with protein pacing leads to a more diverse gut microbiota compared to a calorie-restricted, heart-healthy diet. This finding may significantly influence our understanding of the relationship between the gut microbiome and metabolism, potentially informing new strategies for managing obesity.
The gut microbiome, a complex community of microorganisms residing in the intestines, plays a crucial role in controlling body weight and overall health. Scientists know that nutrient availability can significantly influence this balance.
While both calorie restriction and intermittent fasting (limiting food consumption to certain windows on some days) are known to impact body weight, their effects on gut microbiota have been less clear until now. Protein pacing (spreading protein intake throughout the day rather than consuming it in one meal) also contributes to this dietary impact.
The Study
In this small trial, researchers compared two dietary interventions over eight weeks involving 41 overweight or obese individuals. One group followed a Mediterranean-style, calorie-restricted diet based on U.S. dietary guidelines. The other group adhered to a calorie-restricted regimen that included intermittent fasting and protein pacing (known as the IF-P diet).
Key Findings
Greater Gut Microbiota Diversity: Individuals in the IF-P group experienced a greater diversity of gut microbiota compared to the calorie-restricted group.
Reduced Gastrointestinal Symptoms: Participants on the IF-P diet reported fewer gastrointestinal issues.
Loss of Visceral Fat: The IF-P group showed a more substantial reduction in visceral fat.
Increased Lean-Associated Gut Microbes: The IF-P diet increased certain gut microbes associated with a leaner body type.
Boost in Circulating Proteins and Amino Acids: This group also saw an increase in proteins and amino acids linked to weight loss and fat oxidation.
Dr. Duane Mellor, dietitian and spokesperson for the British Dietetic Association and honorary academic fellow at Aston University, commented on the study: “While it is an interesting study, suggesting protein pacing and intermittent fasting help to support weight loss, as shown in a study published in 2023, in this analysis this appeared to be linked to improved gut bacteria levels.”
Considerations and Limitations
Dr. Mellor noted that it’s unclear whether the observed effects are due to higher protein levels in the IF-P diet, the intermittent fasting itself, higher fiber content, or a combination of these factors. He added that the higher fiber content in the IF-P diet at least partly explains the differences in gastrointestinal health and gut microbiota.
Despite the study’s careful design, Mellor emphasized its limitations, including its small sample size and the use of supplements provided by the study funder, Isagenix, a supplement manufacturer. This could make the diet challenging to replicate using readily available foods.
Future Implications
Despite these constraints, the findings could support further studies examining the complex metabolic interactions between diet and the gut microbiome. Understanding these interactions may lead to more effective dietary strategies for managing obesity and enhancing overall health.
About the Expert
Dr. Duane Mellor is an award-winning registered dietitian and science communicator (BDA Media Spokesperson of the Year 2021) and a visiting academic for Aston Medical School. His research interests focus on improving nutrition and health by working with communities to celebrate their heritage through food and help tackle barriers resulting from societal inequalities.