Dieting Changes Your Gut Microbiome

Every person’s gut microbiome is unique. Many probiotic supplements sold in grocery stores may not effectively bolster gut health for everyone, she says. The researcher, who specializes in the role of the gut microbiome in obesity and cardiometabolic disease, instead points to the importance of enhancing a diverse microbiome.

Research by Stanislawski and others in the CU School of Medicine aims to understand the relationship between changes in diet and the microbiome. Some of this work uncovers possible routes by which alterations in gut microbiota may influence metabolism during a dietary weight loss intervention.

Daily caloric restriction vs. Intermittent fasting

Stanislawski collaborated with CU Department of Medicine associate professor Vicki Catenacci, MD, who led a behavioral weight loss intervention study comparing the effects of two popular weight loss regimens — intermittent fasting and the more traditional approach of daily caloric restriction.

Stanislawski examined the effects of the intervention on the gut microbiota of the participants and found that both approaches have a positive impact on helping diversify the microbiome.

In one group, participants were instructed to fast three non-consecutive days per week. On fasting days, the participants were to eat about 25% of what they normally eat, and on non-fast days they could eat whatever they wanted. In the other group, participants were instructed to reduce calories every day by the same amount, about 30% of their weight maintenance needs. 

Participants were also given behavioral support during the intervention and advised about ways to improve their overall diet quality as well as encouraged to increase their physical activity levels.

The results from the study suggest that, in terms of the microbiome’s diversity, both dietary weight loss strategies are equally successful. Similarly, they saw changes in the overall taxonomic structure of the microbiome composition across all participants in both intervention groups.

“This means that you can choose a dietary weight loss strategy that works for you, and either way your microbiome will likely shift and increase diversity,” Stanislawski says.


Emily B. Hill, Iain R. Konigsberg, Diana Ir, Daniel N. Frank, Purevsuren Jambal, Elizabeth M. Litkowski, Ethan M. Lange, Leslie A. Lange, Danielle M. Ostendorf, Jared J. Scorsone, Liza Wayland, Kristen Bing, Paul S. MacLean, Edward L. Melanson, Daniel H. Bessesen, Victoria A. Catenacci, Maggie A. Stanislawski, Sarah J. Borengasser. The Microbiome, Epigenome, and Diet in Adults with Obesity during Behavioral Weight Loss. Nutrients, 2023; 15 (16): 3588 DOI: 10.3390/nu15163588

University of Colorado Anschutz Medical Campus. (2023, August 17). Data researchers connect diet to changes in the microbiome. ScienceDaily. Retrieved August 17, 2023 from 
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