A systematic review and meta-analysis of 23 trials suggest adhering to a low carbohydrate diet for a 6-month period could facilitate remission of diabetes and lead to reductions in body weight.
Insights from a systematic review and meta-analysis of published and unpublished trial data provide clinicians with an overview of the safety and efficacy of low and very-low carbohydrate diets for remission of type 2 diabetes.
Results of the analyses, which included data from nearly two dozen randomized trials, suggest patients adhering to a low carbohydrate diet for 6 months could lead to remission of diabetes without increasing risk for adverse events, but investigators also noted this association appeared to fade at the 12-month mark.
“Moderate to low certainty evidence suggests that patients adhering to LCDs for six months may experience greater rates of remission of diabetes without adverse consequences compared with other diets commonly recommended for management of type 2 diabetes (for example, low fat diets),” wrote study investigators.
With an interest in developing a greater understanding of how specific diets influence development and remission of diabetes, a team led by investigators from the Department of Nutrition at Texas A&M University designed the current study as a meta-analysis and systematic review of trials of the CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception through August 25, 2020. For the current study, investigators hoped to include all randomized clinical trials evaluation low carbohydrate diets and very low carbohydrate diets for at least 12 weeks in patients with type 2 diabetes.
For the purpose of analysis, low carbohydrate diets were defined as fewer than 130 grams per day or less than 26% of a 2000 kilocalorie per day diet and very low carbohydrate diets were defined as less than 10% of calories from carbohydrates. The primary outcomes of interest were the remission of diabetes, weight loss, HbA1c, fasting glucose, and adverse events. Investigators defined remission of diabetes as an HbA1c less than 6.5% or a fasting glucose of less than 7.0 mmol/L. Secondary outcomes of interest included health-related quality of life and biochemical laboratory data. All outcomes were indecently screened, exacted, and assessed for risk of bias and GRADE certainty of evidence at 6 and 12 months of follow-up.
The investigators’ search returned 15,759 citations, which resulted ini the identification of 23 trials for inclusion in their systematic review and meta-analysis. These 23 trials included 1357 participants and 40.6% of outcomes within these trials were judged to be at low risk of bias.
When assessing outcomes at 6 months, low carbohydrate diets were associated with higher rates of diabetes remission than control diets (Risk Difference, 0.32; 95% CI, 0.17-0.47; 8 studies, n=264, I2=58%). Investigators pointed out a smaller, non-significant association was found when assessing remission without medication use.
When assessing outcomes at 12 months, investigators noted data on remission was sparse and observed effects on remission were small or indicated trivial increase in risk of diabetes. Investigators pointed out large improvements were seen when examining weightless, triglycerides, and insulin sensitivity at 6 months, but these effects declined when assessed at 12 months. In an analysis of subgroup assessments, investigators determined very low carbohydrate diets were less effective than low carbohydrate diets for weight loss at 6 months, but noted this effect was explained by diet adherence.
“Considering this and a recent systematic review of cohort studies suggesting that long term LCDs are associated with increased mortality, clinicians might consider short term LCDs for management of type 2 diabetes, while actively monitoring and adjusting diabetes medication as needed,” wrote investigators.
This study, “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,” was published in The BMJ