Research
Mixed
Bariatric surgery, specifically gastric bypass, significantly alters gut microbiota composition, often increasing Bacteroides/Prevotella and decreasing Firmicutes, which may contribute to sustained weight loss.
For morbidly obese individuals, bariatric surgery can lead to favorable changes in gut microbiota, such as increased Bacteroides/Prevotella, which may support weight loss maintenance. This is a last-resort option for those who have not succeeded with lifestyle changes.
GoodSupportsHIGH confidence
The investigation established that after surgery the levels of Bacteroides/Prevotella were higher than they had been prior to surgery. This increase brought the Bacteroides/Prevotella more closely in line what that observed in the lean controls.
Why this rating
Multiple studies are cited showing consistent changes in microbiota post-surgery.
Source
The gut microbiota and its relationship to diet and obesity
Siobhan F. Clarke et al. · Gut Microbes · 2012
DOI 10.4161/gmic.20168
narrative_reviewCited 460×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Dietary interventions, particularly those involving calorie restriction, high protein, or specific macronutrient compositions, can alter gut microbiota composition, with changes often correlating with weight loss outcomes.Good
- Obesity is associated with a gut microbiota composition characterized by a lower proportion of Bacteroidetes and a higher proportion of Firmicutes compared to lean individuals, a pattern observed in both murine models and human studies.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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