Clinical effectiveness of very low calorie diets. Systematic review and meta-analysis of randomised controlled trials

Abstract

Very low calorie diets (VLCDs) are an option for the management of obesity, but are not used in primary care. This abstract presents an ongoing review to examine whether VLCDs could be an effective option for GPs to manage obesity. Literature databases were searched from database inception to February 2013. Studies were included if they were randomised controlled trials that recruited overweight or obese adults, with or without comorbidities. The intervention needed to incorporate a VLCD and comparator could be a no intervention control or an intervention that could be given in primary care. The primary outcome was weight change at 12 months from baseline. Secondary outcomes were HbA1c, lipids, and blood pressure and we recorded adverse events. We included 11 studies in the analysis which randomised 425 participants to VLCD and 349 participants to a comparator. Compared with a behavioural weight loss programme, VLCDs achieved an additional −4.1 kg (−7.3 to −0.8) greater weight loss at 12 months. Using baseline observation carried forward (BOCF), the differencewas −3.4 kg (−6.7 to −0.05). The difference in weight loss using BOCF at 18–24 months was −1.6 kg (−3.3 to −0.01) and at 42–60 months was −1.5 kg (−4.0 to 1.0). Data on secondary outcomes, adverse events and subgroup analyses will be available for an updated abstract and be presented at the conference. We will conclude on whether VLCDs appear safe and effective and hence a useful option for achieving weight loss in primary care.