The Economic Value of Reducing Adult Obesity in Greece: A Prevalence-Based Dynamic Modelling Study

Background/Objectives: Obesity represents a major and growing economic challenge, yet evidence on its long-term economic burden and the potential value of sustained reductions in obesity prevalence remains limited in Greece. This study estimated the future economic burden of adult obesity in Greece and quantified the gross healthcare and societal costs avoided from alternative sustained reductions in obesity prevalence. Methods: A prevalence-based, top–down dynamic model was developed for the Greek adult population over 2026–2055. The analysis adopted a societal perspective and incorporated direct medical costs associated with obesity pharmacotherapy, bariatric surgery, and 36 obesity-related comorbidities, together with productivity losses from absenteeism and presenteeism. Adult population and obesity prevalence were projected using exponential smoothing, while population-attributable fractions (PAFs) linked obesity prevalence to comorbidity-related expenditure. The primary illustrative scenario assumed a hypothetical 5% annual relative reduction in adult obesity prevalence, rather than a 5% reduction in individual body weight. Potential gross costs avoided were estimated by comparing the projected obesity-attributable economic burden under this scenario with the corresponding burden under the status quo trajectory over the 2026–2055 modelling horizon. Costs were expressed in 2025 euros and discounted at 5% annually. Scenario, deterministic, and probabilistic sensitivity analyses were conducted. Results: Under the status quo, adult obesity prevalence was projected to increase from 29.24% in 2025 to 42.87% in 2055, while annual obesity-attributable costs increased from EUR 4.23 billion to EUR 5.11 billion. Direct medical costs accounted for 86.38% of cumulative expenditure. Under the 5% annual prevalence-reduction scenario, obesity prevalence declined to 6.28% by 2055, generating cumulative undiscounted gross costs avoided of EUR 71.12 billion and discounted gross costs avoided of EUR 29.25 billion. Probabilistic analysis produced discounted gross costs avoided of approximately EUR 27.85 billion, with a 95% uncertainty interval of EUR 23.83–31.61 billion. Conclusions: Adult obesity is projected to impose a substantial economic burden on Greece, with the findings illustrating the potential gross healthcare and societal costs avoided under hypothetical, sustained reductions in adult obesity prevalence, rather than the expected economic outcomes of specific interventions. These estimates are conditional on the assumed prevalence trajectories and do not establish the feasibility or cost-effectiveness of achieving such reductions.