Body Composition Changes Following a Very-Low-Calorie Pre-Operative Diet in Patients Undergoing Bariatric Surgery
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.
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.
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.
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.
KeywordsBody composition Very-low-calorie diet Fat mass Lean body mass Bariatric
Compliance with Ethical Standards
Approval for the study was obtained from the St Vincent’s Human Research Ethics Committee in June 2017. This study was conducted according to the guidelines from the National Health and Medical Research Council. Informed written consent was obtained from each participant after discussing the objectives and nature of the study.
Conflict of Interest
The authors declare that they have no conflict of interest.
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