Low-GI diets help reduce weight in prediabetic, diabetic individuals

Diets with low glycaemic index (GI) appear to be beneficial for glycaemic control and may even reduce body weight in people with prediabetes or diabetes, according to the results of a systematic review and meta-analysis.

The investigators tried to determine whether low-GI diets were indeed superior to other diet types in lowering measures of blood glucose control in people with type 1 or type 2 diabetes or impaired glucose tolerance.

PubMed, the Cochrane Library, Embase and clinical trials registries were searched for published and unpublished studies through 1 March 2019. Fifty-four randomized controlled trials in adults or children with impaired glucose tolerance, type 1 or type 2 diabetes were included in the meta-analysis.

The investigators then synthesized continuous data using a random-effects, inverse variance models and presented these as standardized mean differences with 95 percent confidence intervals (CIs).

A low-GI diet effectively reduced glycated haemoglobin (HbA1c), fasting glucose, body mass index, total cholesterol and low-density lipoprotein. However, it did not have any effect on fasting insulin, high-density lipoprotein, triglycerides, Homeostatic Model Assessment of Insulin Resistance scores or insulin requirements.

The reduction in fasting glucose and HbA1c had an inverse relationship with body weight. Moreover, studies of the longest duration demonstrated the greatest decrease in fasting blood glucose.

“Low-GI diets are thought to reduce postprandial glycemia, resulting in more stable blood glucose concentrations,” the investigators noted.