FADIS: Fast-food attributed diabetes index study: An ecological State-level exploration of nutritional transitions and diabetes burden in India.

Background and objectives India's rapid urbanisation, economic liberalisation, and rising fast food consumption are driving a nutritional transition that parallels the growing epidemic of non communicable diseases, particularly type 2 diabetes mellitus. This study examines the association between fast food expenditure and diabetes prevalence across 18 Indian States, stratified by gender and urban-rural residence. Methods The fast-food attributed diabetes index study (FADIS) utilised publicly available State-level data to evaluate correlations between fast food spending and diabetes prevalence. A novel framework, DIAGRAM (diabetes and intake gradient analysis model), was applied to parse these associations across urban and rural men and women. The WEIGHT (women's elevated intake and glucose-health evaluation tracker) model assessed the prevalence of overweight as a predictor of diabetes in women. Results We found a strong positive correlation between fast food expenditure and diabetes prevalence among urban populations, specifically urban men (r=0.653, P=0.003) and urban women (r=0.619, P=0.0062). Rural patterns were less consistent and weaker. The WEIGHT model identified the prevalence of overweight as a significant contributor to diabetes risk among women. Interpretation and conclusions In this ecological analysis, we found that fast-food expenditure had a strong correlation with diabetes prevalence, particularly among urban men and women. In women, overweight prevalence rather than fast-food expenditure emerged as the significant predictor in multivariable analyses. These findings highlight the need for gender-sensitive and region-specific public health strategies to address India's evolving nutritional transitions and diabetes burden.