Discordance between percentage of excess weight loss and body composition outcomes after bariatric surgery: a retrospective observational study.

Authors

Maite Aguas-Ayesa, Patricia Yárnoz-Esquíroz, Laura Olazarán, Camilo Silva, Piero Portincasa, Javier Gómez-Ambrosi, Gema Frühbeck

Published in

The American journal of clinical nutrition. Pages 101469. Aug 08, 2026. Epub Aug 08, 2026.

Abstract

Percentage of excess weight loss (%EWL) is one of the most commonly used criteria for assessing outcomes after bariatric surgery (BS). However, this measure is based on weight and does not provide information on body composition.
Our aim was to evaluate the achievement of different anthropometric objectives 12 months after BS, to analyze the concordance between %EWL and fat mass percentage (FM%) and waist-to-height ratio (WHtR) as well as to explore the differences in body composition and biochemical variables between and within groups of %EWL.
583 participants (160 males/423 females) who underwent BS (109 sleeve gastrectomy/474 Roux-en-Y gastric bypass) were included in a retrospective observational study. %EWL, FM% and other anthropometric and biochemical variables at 12 months post-surgery were analyzed using chi-square test and one- or two-way ANOVA.
95% of the cohort achieved a %EWL ≥50% while 63% achieved a %EWL ≥75%. However, one-third of patients with %EWL ≥75% had a FM% still corresponding to obesity, and 65% had a WHtR ≥0.50. Patients with "High %EWL and High FM%" had higher body mass index, FM%, waist-to-hip ratio, WHtR, trunk fat percentage, visceral adiposity and relative fat mass than those with "High %EWL and Low FM%" group (P < 0.001). Patients with "High %EWL and Low WHtR" had lower levels of uric acid, blood pressure, and triglyceride-glucose index, as well as higher levels of quantitative insulin sensitivity check index than patients with "High %EWL and High WHtR" (P < 0.05).
Body composition variability within groups remains high with a significant number of patients who, despite reaching the %EWL threshold, still exhibiting a high FM% and WHtR. Complementing the %EWL with body composition measures allows for better characterization of patients as well as identification of those with a more unfavorable metabolic state not only at diagnosis but also at follow-up.

PMID:
42570866
Bibliographic data and abstract were imported from PubMed on 09 Aug 2026.

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