Type 5 diabetes: Recognizing a distinct form of malnutrition-related diabetes in the global health landscape

Diabetes mellitus encompasses a heterogeneous group of metabolic disorders characterized by chronic hyperglycemia. While types 1 and 2 diabetes are well-established, emerging evidence supports the recognition of distinct forms that do not fit these traditional classifications. This comprehensive review examines type 5 diabetes, officially recognized in 2025, which affects an estimated 20–25 million people worldwide, primarily young males with low body mass index in low- and middle-income countries. Unlike other forms of diabetes, type 5 is characterized by insulin secretory defects rather than insulin resistance, preserved but diminished C-peptide response, absence of autoimmune markers, and resistance to ketosis despite significant hyperglycemia. Recent metabolic studies have confirmed its unique pathophysiological profile, demonstrating that affected individuals are relatively insulin sensitive despite high insulin requirements. Evidence suggests type 5 diabetes stems from impaired pancreatic development due to early life malnutrition, highlighting important connections between developmental programming and adult metabolic health. This review synthesizes current knowledge on epidemiology, pathophysiology, clinical presentation, diagnostic approaches, and management strategies for type 5 diabetes while identifying crucial research gaps and public health implications. Recognition of type 5 diabetes as a distinct entity represents a significant advancement in understanding the diverse spectrum of diabetes and has important implications for clinical practice and health policy in regions where this condition is prevalent.