Low energy diets using formula meal replacements are the most effective for weight loss in type 2 diabetes, University of Otago researchers have discovered.
Led by Otago adjunct Professor of Medicine Mike Lean, along with Dr Andrew Reynolds and researchers from Thailand and the United Kingdom, the team analysed published data on 19 different diets covering Mediterranean, vegetarian, vegan, high fat, and low carbohydrate ketogenic diets to determine which was best for achieving and then maintaining weight loss in type 2 diabetes.
They found that a range of low energy diets were suitable for weight loss, but that the greatest weight loss was achieved with total diet replacement for eight to 12 weeks. They led to an average 6.6kg more weight loss compared with food-based low-energy diets.
Dr Andrew Reynolds.
Dr Reynolds, a Research Fellow in the Department of Medicine, says awareness of the benefits of weight loss for type 2 diabetes is high, but both patients and healthcare practitioners need clearer guidance on how to achieve this.
“This research is important to inform choice for those looking to lose weight. We see 1,001 diets advertised for weight loss, but it can be hard to know which ones work.
“I hope this research informs discussions with physicians that are flexible to what the patient wants. So, if they want to lose weight on a plant-based diet, or a higher protein diet, or a meal-replacement diet, then they are supported to do so.”
In Aotearoa, more than one million people are affected by type 2 diabetes – about 7 per cent of the population has the chronic disease and a further 18 per cent have prediabetes.
Low carbohydrate diets were no better than higher carbohydrate diets for weight loss, with the macronutrient content having little impact compared with the energy intake.
While the research was undertaken to inform European guidelines for diabetes management, it has world-wide applications, Dr Reynolds says.
“These guidelines are written for physicians, to given them clear, factual information to share and discuss with their patients. Patients may choose to discuss weight loss with their GP, so it is important they have up-to-date, evidence-based advice on what works.”
But the work does not stop there. Successful long-term maintenance of weight may require different behavioural strategies. Few trials have reported data beyond 12 months.
“Well-conducted research is needed to assess longer-term impacts on weight, blood sugar control, clinical outcomes and diabetes complications,” he says.
“I think that this research gives us great freedom to work with patients to find weight loss diet that are sustainable and work for them, so long as it is low in energy and meets the requirements for nutrients such as protein and fibre.”