Lean Mass Seen as Factor in Maintaining Weight Loss After Gastric Bypass

November 4, 2017

By Kerry Young

OXON HILL, Md -- November 4, 2017 -- Boosting both the amount of energy the body burns at rest and its lean mass may help people maintain weight loss after Roux-en-Y gastric bypass (RYGB), according to a study presented here at Obesity Week 2017, the joint Annual Meeting of the American Society for Metabolic & Bariatric Surgery (ASMBS) and The Obesity Society (TOS).

A study of 30 people who had undergone RYGB found rates of higher resting energy expenditure (REE) and lean mass (LM) among patients who had succeeded in keeping the weight off, reported Prapimporn Shantavasinkul, MD, Ramathibodi Hospital of Mahidol University, Bangkok, Thailand.

All participants all had achieved at least a 50% reduction of their excess weight at the 1-year mark. The researchers then checked on how these participants fared at least 2 years following their operations, classifying the participants as falling into either the weight-regain (WR) group or the sustained-weight loss (SWL) group, based upon whether weight regain was equal to or greater than 15% of postoperative lowest weight.

All patients were matched by age, sex, preoperative body mass index, preoperative diabetes status, and time since RYGB surgery.

Dr. Shantavasinkul said that some patients gained weight despite strict adherence to medical recommendations, raising questions about how metabolism plays a role in maintaining weight loss.

Compared with the SW group, the WR group had significantly lower REE (15.5 + 2.7 kcal/kg/day vs 21.4+3.1 kcal/kg/day; P< .001) on a weight-adjusted basis, lower % lean mass (%LM; 53.2 + 5.0% vs 63.9 + 8.1%; P< .001), and a greater percentage of fat mass (%FM; 44.8 + 5.2% vs 33.1 + 8.2%; P< .001).

Dr. Shantavasinkul said the findings highlight the importance of protein in the diet, referring to research beyond the scope of the study she presented at Obesity Week.

“Normally the way that we can increase our resting energy expenditure is to increase our lean mass, and the way that we can increase our lean mass is try to increase protein intake along with increased physical activity,” she said.

The study excluded people who had a prior history of surgical failure, who were currently taking weight-loss medications, and were pregnant or lactating. Dr. Shantavasinkul cited the small sample size as a drawback of the work.

[Presentation title: Energy Expenditure and Body Composition Contributed to Weight Regain After Roux-en Y Gastric Bypass Surgery. Abstract A130]

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