gut microbiome diet

Impacts of Lifestyle and Microbiota-Targeted Interventions for Overweight and Obesity on the Human Gut Microbiome: A Systematic Review

10 December 2025

Lee YT, Akan A, Önel DB, Medawar E, Jensen DEA, Villringer A, Witte AV.

Summary

Of course. Here is a summary of the research study for a health-conscious reader. ### **Summary of the Study** **1. Plain-Language Summary** This large review of 87 clinical trials found that while general diet and exercise interventions didn't consistently alter the overall diversity of gut microbes, specific supplements showed more promise. Taking prebiotics effectively boosted beneficial bacteria, while probiotics were linked to modest reductions in body weight and fat. **2. Key Findings** * **Overall Diversity Unchanged:** Most interventions, including broad dietary changes and physical activity, did not cause significant shifts in the overall diversity of the gut microbiome. * **Prebiotics Feed Good Bacteria:** Consuming prebiotics (specific types of fiber) was reliably associated with an increase in beneficial bacteria, particularly *Bifidobacterium*. * **Probiotics Linked to Weight Loss:** Taking probiotic supplements was connected to increased levels of *Lactobacillus* bacteria and, importantly, to small but significant reductions in body weight and body fat. * **Weak Link to Metabolites:** The review found no strong, consistent evidence connecting changes in the gut microbiome to levels of short-chain fatty acids (SCFAs), which are often thought to be a key link between gut health and metabolism. **3. Practical Takeaways for Nutrition and Longevity** For individuals looking to support their gut health for weight management and overall wellness, this study suggests that targeted approaches may be more effective. Incorporating prebiotic-rich foods (like onions, garlic, and asparagus) and probiotic sources (like yogurt, kefir, or supplements) for at least four weeks appears to be a promising strategy. These targeted interventions may offer more direct benefits to the microbiome than general healthy eating alone. **4. Study Limitations** The quality and methods of the studies reviewed were highly inconsistent, making it difficult to draw definitive conclusions. Standardized research is needed to confirm these findings and understand the most effective protocols.

Abstract

Obesity is intricately associated with the gut microbiome, and emerging research suggests that lifestyle interventions, such as dietary changes and active lifestyle, can significantly affect the composition and function of the gut microbiome. However, evidence demonstrating a causal link between these changes and long-term weight loss or metabolic improvements remains limited. This systematic review investigates how overweight- and obesity-targeted interventions, such as dietary modifications, physical activity, supplementation with prebiotics and probiotics, and fecal microbiota transplantation (FMT), manipulate gut microbiome diversity and composition, major metabolites, and weight status. We conducted a systematic literature search and included 87 out of 255 randomized clinical trials with 6086 adults aged 18-84 with a BMI ≥ 25 kg/m<sup>2</sup>. The quality of the included RCTs ranged from very low to moderate risk of bias. Most interventions did not cause any significant changes in microbial alpha or beta diversity, however, positive associations between prebiotic consumption and abundance of Actinobacteria and Bifidobacterium were observed, and intake of probiotics was related to increased levels of Lactobacillus and reduced body weight and body fat. We did not observe strong evidence for associations between SCFA levels, gut microbiome, and obesity. Overall, diversity and heterogeneity in reported outcomes, both in methods and results, were large. Taken together, our findings suggest that overweight- and obesity-targeted dietary interventions of at least 4 weeks, particularly those involving prebiotics and probiotics, have the potential to beneficially alter the gut microbiome, although standardized protocols and harmonized reporting are needed to confirm this through meta-analysis.

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