The report from the Scientific Advisory Committee on Nutrition (SACN), co-chaired with Diabetes UK, suggests that a diet lower in carbohydrates is an effective option up to 6 months for adults living with type 2 diabetes and overweight or obesity.
The report is based on a robust assessment of existing evidence around weight change, blood sugar management, blood fats and medication use.
SACN concludes that for adults living with type 2 diabetes and overweight or obesity, there are beneficial effects of a lower carbohydrate diet for up to 6 months for some of the outcomes considered, including improving blood sugar management.
People on lower carbohydrate diets lost more weight than those on higher carbohydrate diets in the first 3 months but not after, so it's unclear if the benefits of a lower carbohydrate diet are due to this early weight loss.
Overall, the quality of the evidence wasn't strong enough to recommend a lower carbohydrate diet for longer than 6 months.
Douglas Twenefour, co-chair of the joint working group and Deputy Head of Care of Diabetes UK, said:
We know that for most people with type 2 diabetes, managing their weight is key to managing their condition.
Health professionals should support any evidence-based dietary approach that helps achieve long-term weight reduction, and this can include a lower carbohydrate diet.
It is vital that people get the support of their healthcare team, so that any impact on diabetes management or medications can be closely monitored.
Dr Alison Tedstone, Chief Nutritionist at PHE, said:
SACN and Diabetes UK have thoroughly analysed the evidence around this complex issue.
It's not clear whether a lower carbohydrate diet is effective in the longer term. We also don't know whether it would work for all adults living with type 2 diabetes, and not just those living with overweight or obesity.
Adults living with type 2 diabetes choosing a lower carbohydrate diet should aim to include wholegrain or higher fibre foods, a variety of fruits and vegetables and limit saturated fats.
In the short-term studies, reported diets were classed as lower-carbohydrate if they were made up of around 37% carbohydrates, compared to 50% for higher carbohydrate diets.
