Evaluating the Impact of the Most Popular Diets on Glycemic Control in Type 2 Diabetes Mellitus: A Network Meta-Analysis To evaluate the impact of the most popular diets on glycemic control in type 2 diabetes mellitus patients through a network meta-analysis

Abstract

Introduction: Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterised by insulin resistance, progressive beta-cell dysfunction, and hyperglycaemia, affecting more than half a billion individuals globally. Recent research suggests that dietary modifications can effectively regulate blood glucose levels in individuals with T2DM. Therefore, this study aims to evaluate the effectiveness of the most popular nutritional approaches on glycaemic control in T2DM.

Method: A systematic search was conducted on six databases (PubMed, Scopus, Web of Science, Taylor and Francis, EBSCO, and Cochrane) until March 2025. Eligible randomised controlled trials (RCTs) involving adults with T2DM and reporting outcomes on glycated haemoglobin (HbA1c) or fasting plasma glucose (FPG) were included. Network meta-analysis was conducted using a fixed effect model to pool mean difference (MD) and standard deviation (SD) with corresponding 95% confidence intervals (CI) using MetaInsight.

Results: A total of 24 RCTs encompassing seven dietary patterns (intermittent fasting, Dietary Approaches to Stop Hypertension (DASH), conventional, low-carbohydrate, mediterranean, vegan, and ketogenic diet) were included. Findings of direct comparison revealed the ketogenic diet’s significant effectiveness in reducing HbA1c (%) compared to Mediterranean (MD = -0.90, 95% CI = -1.50 to -0.30) and conventional diet (MD = -0.59, 95% CI = -0.83 to –0.36). DASH diet also presented a substantial improvement in FPG (mg/dL) compared to conventional diet (MD = -27.50, 95% CI = -31.39 to -23.61). SUCRA ranking analysis indicated that the ketogenic diet ranked highest in reducing HbA1c, whereas the DASH diet was most effective in lowering FPG compared to other dietary interventions.

Conclusion: Among the evaluated dietary patterns, the ketogenic diet exhibited superiority in long-term glycaemic control. In contrast, the DASH diet showed greater potential for short-term glycaemic improvement. These findings support the tailored use of specific dietary strategies in managing T2DM based on individualised glycaemic targets.

Keywords: DASH diet, dietary interventions, glycaemic control, ketogenic diet, type 2 diabetes mellitus