There is considerable interest in the idea of using very-low-energy diets (VLEDs) in well-motivated people with type 2 diabetes. Significant weight loss occurs and glycaemia can be normalised. So far, however, this has been demonstrated only in studies with fairly small numbers of participants.
In the high-quality systematic review and meta-analysis summarised alongside, the authors looked at all the current literature to describe the efficacy and acceptability of VLEDs in people with type 2 diabetes. Four randomised and five non-randomised studies were identified that met the inclusion criteria. These included a total of 346 participants, with ages ranging from 40 to 70 years and mean BMI ranging from 30 to 51 kg/m2.
Meta-analysis showed that VLEDs (defined as diets comprising ≤800 kcal/day) induced greater weight loss than minimal interventions, standard care or energy-restricted diets (≤1500 kcal/day) at 3 and 6 months. Greater differences in energy prescription between intervention arms were associated with greater differences in weight loss and fasting glucose levels at 3 months. Attrition rates did not differ between the VLED and comparator arms at any measurement point. The attrition rates were low, suggesting either that very well-motivated individuals were recruited; that adhering to VLEDs is no greater challenge than adhering to other weight loss treatments, possibly owing to additional motivation in response to the early experience of considerable weight loss; or a combination of both these reasons.
The conclusion of this review is that VLEDs are effective in causing substantial weight loss among people with type 2 diabetes. Levels of adherence in the studies appear to be high, although behavioural support was often poorly defined. The authors note, however, that most of the trials reported in the analysis were conducted by a small number of research groups.
A large randomised controlled trial of VLEDs in people with type 2 diabetes (DiRECT [Diabetes Remission Clinical Trial]) is currently underway in the UK. The results from this are eagerly awaited.
To read the article summaries, please download the PDF
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