Long‐term Low‐carbohydrate Diets and Type 2 Diabetes Risk: A Systematic Review and Meta‐analysis of Observational Studies

Abstract

Objective: Low‐carbohydrate diets have favorable short‐term effects on body weight and risk factors for cardiovascular disease. However, they are potentially associated with an increased long‐term risk of mortality. Our objective was to elucidate their effects on the incidence of diabetes. Methods: Several databases (MEDLINE, EMBASE, ISI Web of Science, Cochrane Library, and ClinicalTrials.gov) were searched for relevant articles that were published prior to May 2015. Cohort studies with a follow‐up period of at least one year were included. Identified articles were systematically reviewed, and those with pertinent data were selected for inclusion in a meta‐analysis. The pooled risk ratio (RR) with 95% confidence interval (CI) for the incidence of diabetes was calculated using the random‐effects model with inverse‐variance weighting. Results: We included 13 studies in a systematic review, followed by a meta‐analysis using pertinent data. Among the 440,669 people that were included in 11 cohort studies, 27,887 (6.3%) cases of diabetes were documented. The risk of incident diabetes among individuals with a low‐carbohydrate diet was not significantly different from that of individuals with a high‐carbohydrate diet: the pooled RR was 1.03 (95% CI, 0.91–1.16). Conclusion: Low‐carbohydrate diets did not show any benefit on the risk of diabetes. However, this analysis is based on limited observational studies, and large‐scale trials examining the complex interactions between low‐carbohydrate diets and long‐term outcomes are needed.