The 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 type 2 diabetes mellitus (T2DM) management. Current guidelines emphasize individualized nutrition therapy rather than a single universal dietary approach. This narrative review summarizes current dietary strategies for T2DM and examines moderate carbohydrate restriction and the Japanese LOCABO® approach, which combines meal-based carbohydrate targets (20–40 g/meal), a daily target (70–130 g/day), and limited discretionary carbohydrate intake. Research was identified from major diabetes guidelines and peer-reviewed publications, including randomized controlled trials and long-term observational studies. Evidence supporting moderate carbohydrate restriction in general is substantially broader than evidence specifically evaluating LOCABO®. LOCABO®-specific evidence comprises one small RCT and several observational or uncontrolled studies conducted in Japan. These studies provide preliminary signals regarding glycemic efficacy and longer-term metabolic outcomes and have also examined restaurant availability of compatible meals and renal function. However, validated evidence regarding dietary adherence, acceptability, nutritional adequacy, adverse events, long-term cardiovascular outcomes, and international generalizability remains insufficient. Moderate carbohydrate restriction may therefore be considered one evidence-based option within individualized medical nutrition therapy for T2DM, whereas LOCABO® should be regarded as a pragmatic meal-based implementation that requires independent, multicenter, and long-term validation.