Research

Energy balance

Roux-en-Y gastric bypass (RYGB) surgery produces the greatest long-term weight loss and is the most cost-effective intervention for severe obesity (BMI ≥ 35 kg/m2) compared to lifestyle interventions or pharmacotherapy.

For individuals with a BMI of 35 or higher, Roux-en-Y gastric bypass surgery is the most effective and cost-effective treatment for long-term weight loss, significantly outperforming lifestyle interventions and medication like orlistat. While it involves surgery and higher upfront costs, it leads to greater sustained weight reduction.

GoodSupportsHIGH confidence
From RCTs, RYGB produced the greatest long-term weight change [–20.23 kg, 95% confidence interval (CI) –23.75 to –16.71 kg, at 60 months]. ... RYGB was cost-effective compared with no surgery and WMPs, but the model did not replicate long-term cost savings found in previous studies. Conclusions: Roux-en-Y gastric bypass was costly to deliver, but it was the most cost-effective intervention.
Alison Avenell et al. · Health Technology Assessment · 2018

Why this rating

Based on 131 RCTs and a microsimulation model, though limited by generalizability to UK settings and lack of long-term follow-up for some studies.

Source

Bariatric surgery, lifestyle interventions and orlistat for severe obesity: the REBALANCE mixed-methods systematic review and economic evaluation

Alison Avenell et al. · Health Technology Assessment · 2018

DOI 10.3310/hta22680

Meta-analysis · 131 studiesCited 100×
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DOI resolved against Crossref · corpus check 2026-06-10

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