Adherence to the <scp>EAT</scp> ‐Lancet Diet, Genetic Susceptibility and Risk of Obesity and Obesity‐Related Morbidities: A Prospective Cohort Study

AIMS: The EAT-Lancet diet integrates nutritional benefits with environmental sustainability, yet its associations with obesity and obesity-related morbidities (ORMs), and potential interaction with genetic susceptibility, are not fully explored. MATERIALS AND METHODS: This prospective cohort study included 171 561 participants from the UK Biobank. Adherence to the EAT-Lancet diet was quantified using two validated indices (Stubbendorff and Knuppel) derived from 24-h dietary recalls. Genetic risk was characterised using polygenic risk scores (PRS) for body mass index (BMI) and waist-to-hip ratio (WHR). Multivariable logistic and Cox proportional hazards models were used to assess associations of the EAT-Lancet diet index with obesity prevalence and incident ORMs, respectively. RESULTS: During a median 11.9-years follow-up, 48 853 incident ORMs cases were documented. Higher EAT-Lancet diet adherence was associated with a lower prevalence of obesity, irrespective of genetic risk. In fully adjusted models, a higher Stubbendorff EAT-Lancet diet index was associated with a significantly lower risk of ORMs (HR for extreme quartiles = 0.85; 95% CI 0.83-0.87). A significant interaction was observed between the diet index and BMI-PRS (p for interaction = 0.014), with the lowest risk among participants with low BMI-PRS and high diet adherence (HR = 0.70; 95% CI 0.66-0.74). Similar interaction patterns were observed for WHR-PRS, with the lowest risk also found among individuals with low genetic risk and high diet adherence. Results were consistent for the Knuppel index and robust across all subgroup and sensitivity analyses. CONCLUSIONS: Greater adherence to the EAT-Lancet diet is associated with lower obesity prevalence and reduced risk of ORMs. This dietary pattern may partially attenuate genetic susceptibility to obesity, highlighting its potential as an effective strategy for preventing obesity and its related complications.