Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis

Diabetes Res Clin Pract. 2018 May:139:239-252. doi: 10.1016/j.diabres.2018.02.026. Epub 2018 Mar 6.


Nutrition therapy is considered a key component of diabetes management, yet evidence around the ideal macronutrient composition of the diet remains inconclusive. A systematic review and meta-analysis was performed to assess the effects of carbohydrate-restricted diets (≤45% of total energy) compared to high carbohydrate diets (>45% of total energy) on glycemic control in adults with diabetes mellitus. Six databases were searched for articles published between January 1980 and August 2016. Primary outcome was between-group difference in HbA1c change. Individual effect sizes were standardized, and a meta-analysis performed to calculate pooled effect size using random effects. 25 RCTs involving 2412 participants were included. Carbohydrate-restricted diets, in particular those that restrict carbohydrate to <26% of total energy, produced greater reductions in HbA1c at 3 months (WMD -0.47%, 95% CI: -0.71, -0.23) and 6 months (WMD -0.36%, 95% CI: -0.62, -0.09), with no significant difference at 12 or 24 months. There was no difference between moderately restricted (26-45% of total energy) and high carbohydrate diets at any time point. Although there are issues with the quality of the evidence, this review suggests that carbohydrate-restricted diets could be offered to people living with diabetes as part of an individualised management plan.

Keywords: Carbohydrates; Diabetes; Diet; HbA1c; Weight.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Aged
  • Blood Glucose / metabolism*
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Diabetes Mellitus, Type 2 / pathology
  • Diet, Carbohydrate-Restricted / methods*
  • Dietary Carbohydrates / adverse effects*
  • Female
  • Humans
  • Male
  • Middle Aged


  • Blood Glucose
  • Dietary Carbohydrates