Aim: Very low-energy diets are a weight loss strategy that utilises severe and controlled energy restriction to induce rapid weight loss. This review aimed to evaluate their use in terms of efficacy and safety, and to identify for whom they may be effective for weight loss.
Methods: English-language papers examining the use of very low-energy diets for weight loss in adults with a body mass index ≥30 kg/m2 and published between March 2003 and March 2010 were retrieved from health and medical databases.
Results: Eight randomised control trials, two cohort and six pre-post studies were eligible for inclusion and were assessed for methodological quality and had data extracted. The greatest initial weight loss was −22 kg, after 16 weeks of a very low energy diet. Greatest weight loss after follow up was −13.1 ± 8.0 kg and 9.1 ± 9.7 kg (7.7 ± 8.1%) after 1 and 2 years, respectively. Studies comparing the effects in males versus females yielded conflicting results. Very low-energy diets are effective for producing short-term weight loss. However not all initial weight loss is maintained long term.
Conclusion: Future studies using very low-energy diets should conduct more rigorous analyses of dietary adherence and physical activity and should be required to document side effects experienced in order to identify how and for whom they are effective in facilitating long-term weight loss in adults.