Avoiding carbs for six months may cut risk of type 2 diabetes, research suggests

A new study suggests doctors might consider short-term strict low-carbohydrate diets for managing type 2 diabetes, as Jane Dalton explains.

A higher intake of carbohydrates is linked to type 2 diabetes (Getty Images/iStockphoto)

Patients with type 2 diabetes who follow a strict low-carbohydrate diet for six months may have greater rates of remission than if they go on other recommended diets without adverse effects, researchers have found.

Dietitians say carbohydrates – which range from bread and potatoes to sweets and fruit juices – are an important part of a healthy balanced diet. 

But the new study published by The BMJ suggests doctors might consider short-term strict low-carbohydrate diets for managing type 2 diabetes.

Type 2 diabetes, the most common form of diabetes worldwide, is treated largely through diet. But experts say uncertainty remains about which diet to choose, and previous studies have reported mixed results.

The international researchers admit most of the benefits of the six-month diet diminished after 12 months, but say it could be a useful tool as well as monitoring and adjusting medication.

The scientists compared the effectiveness and safety of low-carbohydrate diets (LCDs) and very low-carbohydrate diets (VLCDs) for people with type 2 diabetes, compared with control diets, which were mostly low-fat.

Their findings were based on analysis of 23 randomised trials involving 1,357 participants whose average ages were 47-67.

The researchers found that patients on low-carbohydrate diets achieved better diabetes remission rates after six months than those on control diets.

On average they had a 32 per cent drop in “absolute risk” reduction, meaning that after six months, for every 100 patients, an extra 32 patients found their diabetes had gone into remission.

The low-carb diet also increased weight loss, led to less medication use, and better body fat concentrations at six months.

However, the effects shrank at 12 months, a finding consistent with previous reviews, and some evidence even showed higher cholesterol levels at 12 months and “worsening of quality of life”.

Low-carbohydrate diets were defined as having less than 26 per cent of daily calories from carbohydrates and very-low-carbohydrate diets had less than 10 per cent of daily calories from carbohydrates for at least 12 weeks.

The authors of the peer-reviewed study said their findings were based on “moderate to low certainty” evidence.

Last year, official figures revealed that more than a quarter of all NHS patients who died after being infected with Covid-19 had diabetes.

Dan Howarth, of charity Diabetes UK, said: “For some people with type 2 diabetes, losing weight through a low-calorie weight-loss programme can put their type 2 diabetes into remission. This research shows that weight loss is key to remission and that a low-carbohydrate diet is one of many ways to achieve weight loss, but we need to understand more about the long-term effects of low-carb diets, particularly on quality of life and other aspects of health.”