New research that compared three popular diets found that 5:2 intermittent fasting brought the best improvements in blood sugar and insulin response in people with type 2 diabetes and obesity.
In the first study of its kind, researchers compared how effective three different dietary interventions are in managing type 2 diabetes with obesity: intermittent energy restriction (IER), time-restricted eating (TRE) and continuous energy restriction (CER).
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Intermittent energy restriction (5:2) is when someone eats normally for five days a week and significantly reduces their calorie intake for two days, while time-restricted eating is when eating is restricted to a 10-hour window.
Continuous energy restriction is continuous calorie cutting.
While all three diets were shown to improve blood sugar levels and body weight, the absolute decrease in HbA1c and body weight was most significant in the 5:2 fasting group.
Haohao Zhang, from The First Affiliated Hospital of Zhengzhou University in China, said: “The research fills a gap in directly comparing 5:2 intermittent energy restriction with a 10-hour time-restricted eating in patients with obesity and type 2 diabetes.
“The findings provide scientific evidence for clinicians to choose appropriate dietary strategies when treating such patients.”
The study was carried out between November 2021 and November 2024, with 99 patients assigned to one of the three diets with supervision from nutritionists.
From the initial group, 63 patients completed the study.
The final group was made up of 18 females and 45 males, with an average age of 36.8 years, a mean diabetes duration of 1.5 years, a baseline BMI of 31.7, and an HbA1c of 7.42%.
The IER group saw significant reductions in fasting blood glucose and triglycerides, alongside increased Matsuda index, which is a measure of insulin sensitivity.
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Mild hypoglycaemia was seen in two patients in the IER group and the TRE group, and three patients in the CER group.
More people stuck to the IER diet (85%), followed by the CER group at 84% and the TRE group at 78%.
