Efficacy and acceptability of very low energy diets in overweight and obese people with Type 2 diabetes mellitus: a systematic review with meta-analyses.

Abstract

To explore the efficacy and acceptability of very low energy diets in overweight or obese adults with Type 2 diabetes. Controlled trials and qualitative studies of individuals with Type 2 diabetes that compared very low energy diets with standard care, minimal interventions, other weight loss interventions, less intensive very low energy diet interventions and very low energy diets with additional components were eligible for inclusion. Meta-analyses of changes in weight, blood glucose levels and attrition rates were performed. Acceptability of very low energy diets was assessed by attrition rates, number and severity of side effects, and by qualitative evaluations of the interventions. Four randomized, five non-randomized controlled trials and no qualitative studies (21 references, 9 studies, 346 participants) were identified. Meta-analyses showed that very low energy diets induced greater weight losses than minimal interventions, standard care or low energy diets at 3 and 6 months. No conclusive evidence for differences in outcomes between very low energy diets and Roux-en-Y gastric bypass surgery was found. Greater differences in energy prescription between intervention and comparator arms were associated with greater differences in weight loss and fasting blood glucose levels at 3 months. Attrition rates did not differ between the very low energy diets and the comparator arms at any measurement point. Very low energy diets are effective in substantial weight loss among people with Type 2 diabetes. Levels of adherence to very low energy diets in controlled studies appear to be high, although details about behaviour support provided are usually poorly described.