17/12/2025
Fasting-style diets rewire your brain–gut connection — and help you shed serious weight.
Intermittent energy restriction (IER), a fasting-style diet involving carefully controlled calorie intake and regular low-intake days, appears to trigger dynamic changes in both the gut and the brain of people with obesity.
In a 62-day study of 25 adults with obesity, participants lost an average of 7.6 kilograms (about 7.8 percent of their body weight) while researchers tracked alterations in brain activity and gut microbiome composition.
Using functional MRI, the team observed changes in several regions tied to appetite control and addiction, including the inferior frontal orbital gyrus, an area central to executive function and willpower around eating. At the same time, stool and blood analyses revealed that shifts in specific gut bacteria were tightly linked with activity in these brain regions, suggesting a closely coupled brain–gut–microbiome response to dietary restriction.
The findings point to a two-way communication system in which the gut microbiome produces neurotransmitters and other molecules that can reach the brain via nerves and circulation, while the brain, in turn, shapes eating behavior and thus nutrient supply to gut microbes. Certain bacterial groups, such as Coprococcus comes and Eubacterium hallii, showed negative associations with activity in brain areas governing self-control, hinting that microbial changes may influence how strongly the brain responds to food-related cues.
Although the precise mechanisms remain unclear, this work supports the idea that targeting specific gut microbes or brain circuits could eventually help improve weight-loss outcomes and long-term weight maintenance in the more than one billion people worldwide living with obesity.
References (APA style)
Nield, D. (2025, December 8). *A fasting-style diet seems to result in dynamic changes to human brains*. ScienceAlert.
Wang, X., Wang, L., Zeng, Q., et al. (2023). Weight loss changes gut microbiota and is associated with altered activity in obesity-related brain regions. *Frontiers in Cellular and Infection Microbiology, 13*, 1269548.