Research
Mixed
Fecal Microbiota Transplantation (FMT) from lean donors does not result in significant weight loss or improved metabolic health in humans with obesity, despite showing benefits in some animal models.
Do not pursue FMT for weight loss at this time, as human trials have not shown benefit. Focus on dietary interventions which are more accessible and have stronger evidence for long-term health.
GoodRefutesHIGH confidence
two placebo-controlled pilot studies in humans with obesity found that treatment with FMT capsules from lean donors did not result in significant weight loss or improve metabolic health.
Why this rating
Based on multiple placebo-controlled human trials showing null results for weight loss.
Source
The Role of the Gut Microbiota in the Gut–Brain Axis in Obesity: Mechanisms and Future Implications
Jamie van Son et al. · International Journal of Molecular Sciences · 2021
DOI 10.3390/ijms22062993
narrative_reviewCited 80×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Gut microbiota dysbiosis in obesity contributes to low-grade inflammation and increased fat storage through mechanisms including increased gut permeability (leaky gut), systemic lipopolysaccharide (LPS) circulation, and altered signaling of satiety hormones (GLP-1, PYY, ghrelin) via the gut-brain axis.Moderate
- Short-chain fatty acids (SCFAs) produced by gut microbiota from dietary fiber can influence satiety, energy expenditure, and glucose metabolism, but human trials on oral SCFA supplementation have shown mixed or null results for improving glucose metabolism or vagal tone.Moderate
Related findings · Mixed
- Bariatric surgery (VSG and RYGB) is the most effective and sustainable treatment for obesity, producing marked and sustained weight loss that non-surgical interventions cannot match.Strong
- Severely protein-deficient diets (2–3% energy) induce lean body mass loss and metabolic imbalance, whereas adequate protein intake (0.66 g/kg/d minimum) is a prerequisite for maintaining muscle, bone, and physiological function.Strong
- For patients with Class III obesity (BMI >39.9 kg/m2), metabolic bariatric surgery (MBS) is significantly more effective than any currently approved medication, with BilioPancreatic Diversion (BPD) showing the highest estimated weight loss.Strong
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