Objective To analyze the spatiotemporal evolution of the global and Chinese burden of Crohn's disease, and to explore the potential causal roles of metabolic remodeling and unhealthy lifestyles accompanying Westernized dietary in the surging incidence of Crohn's disease. Methods Based on data from the Global Burden of Disease Study (GBD) 2023, the epidemiological trends and underlying period effects of Crohn's disease from 1990 to 2023 were dissected by Joinpoint regression and an age-period-cohort model, and the disease burden from 2024 to 2035 was predicted by a Bayesian age-period-cohort (BAPC) model. Meanwhile, multi-phenotype Mendelian randomization (MR) analysis was performed based on the genome-wide association study summary data to evaluate the causal associations of isolated dietary components, alcohol consumption, and secondary body fat distribution traits with Crohn's disease. Results Globally, the incidence of Crohn's disease had plateaued, while the incidence in China was in a rapid ascending phase (average annual percentage change: 2.291%), characterized by a younger age of onset and a marked period-based surge from 2004 to 2013. Primary MR analysis showed that neither isolated dietary components nor overall body mass index (BMI) represented major risk factors for Crohn's disease, whereas elevated trunk fat mass (OR=1.76, P=0.016), higher body fat percentage (OR=2.35, P=0.024), and alcohol consumption (OR=2.45, P=0.040) increased the risk of Crohn's disease. BAPC model projections revealed that the incidence and prevalence of Crohn's disease in China will rebound and grow over the next decade. Conclusion The rapid rise in Crohn's disease burden in China is not only related to improved diagnostic capability, but also more likely to be closely associated with central obesity and gut barrier disruption caused by unhealthy lifestyles. In the future, early prevention and control should be prioritized, particularly body fat management and health education for young adults, to address the upcoming burden of high disease prevalence.