What is Weight Loss after Bariatric Surgery Expressed in Percentage Total Weight Loss (%TWL)? An Updated Systematic Review

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Percentage total weight loss (%TWL) is a key metric for assessing outcomes after metabolic and bariatric surgery (MBS).
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The systematic review updates evidence on %TWL following Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and one anastomosis gastric bypass (OAGB).
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A total of 49 studies were included in the analysis, with significant data from registry-based studies involving over 119,000 patients.
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Pooled %TWL values were calculated, showing 35.9% for OAGB, 32.9% for RYGB, and 32.9% for SG within 24 months post-surgery.
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The review emphasizes that pooled values should be interpreted as descriptive summaries rather than formal comparative estimates.

Obesity Surgery

by Rutger Franken, Felix Hers, Redouan El Ajraoui, Kelly Tieken, Ralph de Vries, Dennis Souverein, Max Nieuwdorp, Victor Gerdes, Arnold van de Laar
June 12, 2026

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