In the past, obesity was erroneously viewed primarily through the lens of personal responsibility. The flawed prevailing belief was simple: eat less, move more, and weight loss would follow. Today, that understanding has fundamentally changed. Obesity is increasingly recognized as a complex, chronic, relapsing disease influenced by genetics, environment, psychology, and the social determinants of health.¹,³

One of the most important advances in obesity science has been that obesity is not simply the result of poor lifestyle choices. Twin and family studies suggest that genetic factors account for 45–75% of variation in body mass index (BMI).¹ While genetics alone cannot explain the dramatic and rapid rise in obesity rates over recent decades, researchers have linked this increase to significant environmental and societal changes, including greater consumption of highly processed foods, reduced physical activity, disturbed sleep, chronic stress, and socioeconomic disparities.¹

There has also been an evolution in scientific thinking beyond the limitations of BMI as the sole measure of obesity. A recent expert consensus recommends that BMI should primarily be used as a screening tool and supplemented with measures of adiposity, such as waist circumference or waist-to-height ratio, when assessing an individual’s health risk.¹,³ The 2025 Lancet Commission introduced the concepts of clinical obesity and pre-clinical obesity, distinguishing between excess adiposity that is already causing organ dysfunction and excess adiposity that primarily confers future health risk.³ This represents a significant shift toward defining obesity by its impact on health and function rather than body size alone.

Treatment options have evolved just as rapidly. Recent obesity management medications can achieve levels of weight loss that historically were only achievable through procedural interventions.² At the same time, metabolic bariatric surgery (MBS) has evolved to a safe, well-established and highly effective treatment, delivering substantial and durable improvements in weight, metabolic health, and obesity-related complications.⁴ The long-term effectiveness of MBS has been demonstrated across a wide range of obesity-related outcomes, including diabetes, cardiovascular risk, and quality of life.⁴

Increasingly, the future of obesity care is being framed not as a competition between medications and surgery, but as a coordinated approach to chronic disease management. Experts advocate combining and sequencing therapies according to patient need, similar to approaches used in oncology, cardiology, and diabetes care.⁴,⁵ The International Federation for the Surgery and Other Therapies of Obesity and Metabolic Disorders (IFSO) recently stated that medical therapy and surgery should be viewed as complementary rather than mutually exclusive treatment options.⁴ Emerging evidence also suggests that combining surgery with structured lifestyle support, pharmacotherapy, or other adjunctive approaches may improve outcomes compared with single-modality treatment alone.²,⁵ Cohen et al. further develop this concept into a stage-adapted model in which behavioral, pharmacological, endoscopic, and surgical interventions are selected and sequenced according to disease severity, comorbidity profile, risk of progression, treatment response, and patient preference.⁶

This evolution in science has important health policy implications. Yet many healthcare systems continue to rely heavily on BMI-based eligibility criteria, despite growing recognition that BMI alone is an inadequate measure of obesity-related disease burden.¹,³ Access to effective treatment remains constrained by reimbursement restrictions, inadequate infrastructure, and persistent misconceptions about the causes of obesity.¹ Weight stigma also continues to influence attitudes among patients, healthcare professionals, payers, and policymakers, creating additional barriers to diagnosis and treatment.¹

Policy discussions often remain heavily focused on prevention, while overlooking the needs of the millions of people already living with obesity.¹ Obesity is increasingly recognized not only as a health challenge, but also as an economic one, with major consequences for healthcare expenditure, workforce participation, productivity, and national economic performance.¹ This growing health and economic burden highlights the importance of evaluating obesity treatments not only by their upfront costs, but also by their potential long-term clinical and health-system value within a multimodal care pathway.¹˒⁴ 

If obesity science has undergone a paradigm shift, policy must do the same. Future obesity strategies should recognize obesity as a chronic disease, move beyond BMI alone, support equitable access to evidence-based therapies, and enable integrated care pathways that combine prevention, behavioral support, pharmacotherapy, surgery, and long-term follow-up.¹,⁴,⁵,⁶

The question is no longer whether obesity deserves treatment. The question is whether our healthcare systems are prepared to align policies with science.¹,³

References:

1. Miras AD, Kokkinos A, Tahrani A, et al. The Future of the Obesity Management Landscape: Challenges, Opportunities and Solutions. Obesity Science & Practice. 2026.
   
   
2. Brown WA, Sumithran P, Cowley M, et al. The Future of Obesity Care: Exploring Synergies Between Metabolic Bariatric Surgery, Interventional Endoscopy and Pharmacotherapy. Obesity Surgery. 2026.
   
   
3. Rubino F, Brown WA, Schauer PR, Pattou F, Cohen RV. From BMI to Disease Diagnosis: What Clinical and Pre-clinical Obesity Mean for Surgeons. Obesity Surgery. 2025.
   
   
4. Cohen RV, Prager G, le Roux CW, Lingvay I, Salminen P. International Federation for the Surgery of Obesity Statement on Metabolic Bariatric Surgery After Pharmacotherapy-Induced Weight Loss in Clinical Obesity. Lancet Diabetes & Endocrinology. 2025.
   
   
5. De Luca M, Belluzzi A, Angrisani L, et al. Meta-analysis of Randomized Controlled Trials for the Development of the IFSO-EC Guidelines on Multimodal Strategies for the Surgical Treatment of Obesity. Diabetes, Obesity and Metabolism. 2025.
   
   
6. Cohen RV, Salminen P, Ponce J, Prager G. Where Does Surgery Fit in the Era of Effective Obesity Pharmacotherapy? Positioning Metabolic Bariatric Surgery Within Multimodal Obesity Care. International Journal of Obesity. 2026. doi:10.1038/s41366-026-02215-y.