Effectiveness of low-carbohydrate diets on type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials in Eastern vs. Western populations

Low-carbohydrate diets (LCDs) have emerged as a potential dietary intervention for managing glycemic control, but their effectiveness across different cultural contexts remains unclear. To evaluate the efficacy of LCDs in managing type 2 diabetes, with attention to cultural context, and to clarify how variability in carbohydrate definitions affects interpretation. We searched PubMed, Embase, and Scopus from inception to 1 August 2024 for randomized controlled trials (RCTs) ≥ 12 weeks in adults with type 2 diabetes. We conducted exploratory analyses by Eastern versus Western setting and dose-response meta-regression using actual carbohydrate intake at the follow-up. Twenty-seven RCTs (n = 2,870; 7 Eastern, 20 Western) were included. Across analyzed time points, no arm sustained carbohydrate intake < 10 % of total energy; therefore, findings generalize to low-to-moderate carbohydrate rather than very-low-carbohydrate. LCDs improved glycemia short-term: HbA1c - 0.29 %, with the largest effect at 3 months. Fasting blood glucose decreased overall (-7.12 mg/dL). Weight loss was greatest at 3 months and attenuated thereafter. At 3 months, lower actual carbohydrate intake was related to larger HbA1c and weight reductions. LCDs offer modest, short-term metabolic benefits for type 2 diabetes management, but benefits diminish over time. Cultural context may shape responses, underscoring individualized, culturally tailored care.