Plain language summary
Surgery for the treatment of morbid obesity has become a very common intervention due to the increased prevalence of disease and relative ineffective comparative therapies. The aim of this study was to evaluate overall changes in body composition in bariatric surgery patients undergoing a very-low-calorie-diet (VLCD). The study is a prospective analysis on patients who underwent a 2-week period of VLCD prior to bariatric surgery. A total of 60 patients were enrolled. This study demonstrated that although VLCD appears to induce considerable weight loss in a short period of time, the majority of this is attributable to lean body mass (62.2%) rather than fat mass (37.6%). Another notable finding is that greater losses in weight occur largely at the expense of lean body mass rather than fat mass. Authors conclude that a 2-week VLCD is an effective tool for pre-operative weight reduction. However, a large amount of the total weight loss is attributed to a loss of lean body mass.
Abstract
BACKGROUND Fatty liver in obese patients increases the technical difficulty of bariatric surgery. Pre-operative weight loss with a very-low-calorie diet (VLCD) is commonly used to facilitate surgery. Few studies have quantified the systemic effect of rapid pre-operative weight loss on body composition. The objective of this study is to evaluate body composition changes in bariatric surgery patients undergoing a VLCD. METHODS Body composition assessments were performed between August 2017 and January 2019 using dual-energy X-ray absorptiometry immediately before and after a 2-week VLCD at St Vincent's Hospital Melbourne. Data collected prospectively pre- and post-VLCD included total body weight, excess body weight, body mass index (BMI), lean body mass (LBM), fat mass (FM) and bone mineral content (BMC). The pre- and post-operative results were compared. RESULTS Forty-four patients completed both the 2-week VLCD and body composition assessments. Following a 2-week VLCD, patients lost a mean of 4.5 kg (range - 0.3 to 9.5) in a total body weight and 8.8% (range - 0.9 to 17.1) of excess body weight, with a mean reduction in body mass index of 1.6 kg/m2 (range - 0.2 to 3.1). Loss of LBM was 2.8 kg and was significantly greater than loss of FM, 1.7 kg (p < 0.05). BMC changes were insignificant. CONCLUSION A VLCD is an effective tool for pre-operative weight reduction. In this cohort, a large amount of the total weight loss was attributed to a loss of lean body mass. The impact of significant lean body mass loss and its relationship to short- and long-term health outcomes warrants further assessment.
Methodological quality
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