Role of a Moderately Low-Carbohydrate Diet (LOCABO®) in Glycemic Control and Type 2 Diabetes Management: Current Evidence and Future Perspectives

Medical nutrition therapy is a cornerstone of the prevention and management of type 2 diabetes mellitus (T2DM). Current international guidelines recommend several dietary patterns, including Mediterranean, vegetarian, low-carbohydrate, and Nordic diets, while emphasizing individualized nutrition therapy rather than a single universal die-tary approach. Among these strategies, carbohydrate restriction has consistently demonstrated favorable effects on glycemic control, although concerns remain regard-ing long-term adherence, safety, and applicability across diverse populations. Moderate carbohydrate restriction has emerged as a practical approach that seeks to balance metabolic efficacy with long-term sustainability. LOCABO®, a moderately low-carbohydrate dietary approach developed in Japan, incorporates three key design principles: meal-based carbohydrate targets (20–40 g per meal), daily carbohydrate targets (70–130 g per day), and dietary flexibility through discretionary carbohydrate intake. These features are intended to reduce postprandial glycemic excursions while maintaining nutritional adequacy and facilitating long-term adherence. This narrative review summarizes current evidence regarding dietary strategies for T2DM, discusses the rationale for moderate carbohydrate restriction, and reviews the clinical evidence supporting LOCABO®, including randomized controlled trials, long-term observational studies, implementation research, and safety evaluations. We also address current controversies related to saturated fat intake, non-sugar sweeteners, long-term clinical outcomes, generalizability, and personalized nutrition. Rather than proposing a single optimal dietary pattern, current evidence supports in-dividualized medical nutrition therapy tailored to patients' metabolic characteristics, nutri-tional status, cultural background, and personal preferences. Within this framework, moder-ate carbohydrate restriction represents a practical, evidence-informed, and sustainable op-tion for the management of T2DM and metabolic health. By integrating clinical evidence with pathophysiological mechanisms underlying postprandial glycemic regulation, this review provides a conceptual framework for positioning moderate carbohydrate restriction within contempo-rary personalized nutrition therapy.