Very low-energy and low-energy formula diets: Effects on weight loss, obesity co-morbidities and type 2 diabetes remission - an update on the evidence for their use in clinical practice

The role of formula very low-energy diets (VLEDs, <800 kcal/day) and low-energy diets (LEDs, 800-1200 kcal/day) within clinical practice has regained attention over the last few years. Formula diets can achieve clinically significant weight reduction in the short-term (3-5 months) and new evidence demonstrates that long-term weight loss maintenance (up to 4 years) is achievable. Weight reductions of between 10% and 15% bodyweight have been reported, which is associated with clinically meaningful health outcomes in a number of obesity-related co-morbidities including type 2 diabetes (T2D), obstructive sleep apnoea and osteoarthritis. Recent evidence indicates that using a formula LED with a weight loss maintenance programme can help people with overweight or obesity and T2D achieve remission. Despite this, few healthcare professionals in the UK routinely use LEDs. Concerns about adherence, risk of precipitating eating disorders, safety, cost and long-term efficacy may, in part, contribute to their under use. To help inform healthcare professionals on the use of formula diets within clinical practice, this review examines the current evidence for the use of VLEDs and LEDs for weight loss and weight loss maintenance, and in the treatment of obesity-related co-morbidities, including T2D, osteoarthritis, psoriasis, obstructive sleep apnoea and secondary coronary prevention, with a particular focus on T2D remission.