Improved Glycemic Control and Adiposity With Low Glycemic Index, Load Diets Among Patients With Diabetes

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Investigators conducted a systematic review and meta-analysis to assess the effect of low glycemic index and low glycemic load diets on glycemic control and cardiovascular risk among individuals with diabetes.

For patients with moderately controlled diabetes, a systematic review and meta-analysis found that low glycemic index (GI) and low glycemic load (GL) diets improve glycemic control, adiposity, and lipid profiles. These findings were published in BMJ.

Researchers from the University of Toronto in Canada searched publication databases through May of 2021 for studies of low GI or low GL diets among patients with diabetes. A total of 29 trials comprising 1617 participants were included in this analysis.

The trials consisted of 47% women, 90% had type 2 diabetes, and 93% were adults. Baseline median body mass index (BMI) was 31 kg/m2 and median glycated hemoglobin (HbA1C) was 7.7%.  Hyperglycemia medications were used by 69% of study participants, insulin by 14%, and both treatments by 7%.

The investigators reported a median difference in GI of 12 (range, -32 to -1) and in GL of 29 (range, -77 to 5) between the intervention and control diets. The average intervention and control diets were made up of 49% and 48% carbohydrates, 20% and 19% protein, 32% and 32% fat, 8.2% and 8.6% saturated fat, and 30.7 g/d and 26.3 g/d fiber, respectively.

The low GI/GL diets were associated with a reduction in HbA1C (-0.31%; 95% CI, -0.42% to -0.19%; P <.001).  The low GI/GL diets were also associated with significant reductions in non-high-density lipoprotein cholesterol (-0.20 mmol/L; P <.001), low-density lipoprotein cholesterol (-0.17 mmol/L; P <.001), apolipoprotein B (-0.05 g/L; P =.03), triglycerides (-0.09 mmol/L; P =.04), body weight (-0.66 kg; P <.001), BMI (-0.38 kg/m2; P =.003), fasting blood glucose (-0.36 mmol/L; P <.001), and C-reactive protein (-0.41 mg/L; P =.03).

Among the 10 trials that included data about medication changes after dietary intervention, 2 studies reported a significant reduction after switching to the low GI/GL diet and 4 studies observed a nonsignificant reduction.

This analysis was limited as most comparisons included significant study heterogeneity.

These data supported existing recommendations for individuals with type 1 or type 2 diabetes to consume a low GI/GL diet as these diets were found to be associated with significantly reduced HbA1C, fasting blood glucose, adiposity, and lipid levels.  In addition, some individuals were able to decrease their intake of diabetic medications.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Chiavaroli L, Lee D, Ahmed A, et al. Effect of low glycaemic index or load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: systematic review and meta-analysis of randomised controlled trials. BMJ. 2021;374:n1651. doi:10.1136/bmj.n1651