Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 33441384 · doi:10.1136/bmj.m4743
What was done
A systematic review and random-effects meta-analysis of 23 randomized controlled trials (1,357 adult participants with type 2 diabetes) was conducted to evaluate low-carbohydrate diets (LCDs; <130 g/day or <26% total energy) and very low carbohydrate diets (VLCDs; <10% calories from carbohydrates) lasting at least 12 weeks. Primary outcomes included diabetes remission (HbA1c <6.5% or fasting glucose <7.0 mmol/L, with or without medication), weight loss, glycemic markers, and adverse events assessed at 6 and 12 months.
What was found
At 6 months, patients on LCDs achieved significantly higher rates of diabetes remission defined as HbA1c <6.5% compared to control diets (57% vs 31%; risk difference 0.32, 95% CI 0.17 to 0.47; 8 studies, n=264). When remission was defined as HbA1c <6.5% without medication, effect sizes were smaller and non-significant. Remission benefits were markedly lower in trials enrolling insulin-treated patients. Large improvements in weight loss, triglycerides, and insulin sensitivity at 6 months mostly diminished by 12 months, where remission data were sparse. At 12 months, participants on LCDs experienced a clinically important, but non-significant, worsening of LDL cholesterol and quality of life.
Why it matters
This review shows that while low-carbohydrate diets can promote diabetes remission and metabolic improvements in the short term (6 months), these clinical advantages attenuate substantially by 12 months, likely mediated by reduced long-term dietary adherence.
Limits
Only 40.6% of assessed outcomes were judged to be at low risk of bias. Long-term (12-month) data were sparse, dietary adherence waned over time, and efficacy depended heavily on whether diabetes remission was defined with or without concurrent glucose-lowering medication use.
Cited by
- partial Metabolic therapies can cure type 2 diabetes and eliminate hypertension.