Macronutrient Intake and Dietary Patterns in Indian Adults with and without Type 2 Diabetes: Findings From the Multicentric I-STARCH-1 Study

The I-STARCH (Indian Study to Assess Real-World CarboHydrate Consumption) investigation quantified decadal changes in macronutrient intake and carbohydrate quality among Indian adults by benchmarking a 2025 multicentric cross-sectional survey against STARCH 2014. A total of 1,104 adults were enrolled from twenty-nine healthcare centres across fourteen Indian states. Each participant completed three non-consecutive 24 h dietary recalls, harmonised using the ICMR-NIN Food Composition Tables. Temporal contrasts treated 2014 cohort means as fixed benchmarks. In 2025, carbohydrates contributed 62.1% of total energy (2014: 65.8%), fat 25.1% (2014: 21.4%), and protein 12.8% (2014: 12.8%). Carbohydrate quality declined, with simple sugars comprising 20.3% of total carbohydrate (2014: 10.5%) and fibre providing only 1.8% of energy. Across all geographic zones including north, south, east, and west, macronutrient patterns remained suboptimal, indicating persistent dietary imbalance regardless of regional cereal dominance. Adults with type 2 diabetes reported lower carbohydrate intake (61.0%E) than those without diabetes (64.1%E), although both exceeded the recommended 50-55%E range. The composite Diet-Quality Index (protein%E + fibre%E - simple carbohydrate%E; higher = better) was lower in 2025, reflecting refined carbohydrate substitution without improvements in fibre or protein density. A secondary Protein-Fat Quality Index (PFQI = Protein % E / Fat % E) was also computed to assess balance between protein and fat energy. These findings indicate a continuing nutrition transition in India, characterised by persistent carbohydrate predominance, higher dietary fat, and declining carbohydrate quality. Region-specific dietary policies and clinical practices that promote fibre and protein-rich foods, complex carbohydrate sources, and balanced macronutrient quality are needed to support better metabolic health in India.