In addition to losing weight, intermittent fasting changes the composition of the intestinal bacterial flora and modifies brain activity in areas associated with appetite and addictions: this is shown by a study of 25 obese patients conducted in China under the coordination of Qiang Zeng. People’s Liberation Army General Hospital in Beijing. The findings, published in the journal Frontiers in Cellular and Infection Microbiology, could lead to new strategies to fight obesity and promote good weight control.
Intermittent energy restriction “changes the axis of the human brain, gut, and microbiome,” Qiang Zeng explains. His team found this out by following 25 obese people of both sexes with an average age of 27 and a body mass index between 28 and 45 for two months. For the first 32 days, the patients were given personalized meals with a calorie content that they gradually reduced to a quarter of their initial energy intake. For the next 30 days, they were instead given a list of recommended foods totaling 500 calories per day for women and 600 calories per day for men.
At the end of the study, their body weight decreased by an average of 7.6 kilograms (or 7.8%). As expected, they saw a reduction in body fat and waist circumference. Blood pressure, fasting plasma glucose, cholesterol, and major liver enzymes also decreased similarly: these data suggest that the diet helps reduce obesity-related comorbidities such as hypertension, hyperlipidemia, and liver dysfunction.
Through functional magnetic resonance imaging, the researchers observed that after intermittent fasting, activity in brain regions involved in the regulation of appetite and addiction decreases. At the level of the intestinal microbiome, however, the bacteria Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacterokles uniformis are increasing, while the occurrence of Escherichia coli is decreasing. Further analysis showed that the abundance of E. coli, Coprococcus, and Eubacterium hallii was negatively associated with the activity of a brain region known for its key role in executive functions, including the desire to lose weight. In contrast, the abundance of P. distasonis and Flavonifractor plautii bacteria was positively correlated with the activity of brain areas associated with attention, motor inhibition, emotions, and learning.
Another goal of the researchers will be to understand the mechanism that connects the gut microbiome and the brain in obese people, including during dieting and weight loss.