The STAMPEDE randomized trial compared intensive medical therapy alone with bariatric surgical procedures plus medical therapy in patients with obesity and poorly controlled type 2 diabetes. The study included gastric bypass and sleeve gastrectomy and assessed whether surgery could achieve better long-term glycaemic outcomes. At one year, substantially more patients in the surgical groups achieved the study's stringent glycaemic target without conventional diabetes medication than those receiving medical therapy alone. The surgical groups also achieved greater weight loss, highlighting that the metabolic benefits of bariatric surgery extend beyond the simple mechanical effect of reducing food intake. For clinicians, STAMPEDE changed the way metabolic surgery is viewed. Bariatric procedures can function as disease-modifying interventions in appropriate patients, particularly when obesity and type 2 diabetes remain difficult to control despite intensive medical treatment. The decision to operate still requires individualized assessment of BMI, diabetes severity, comorbidities, operative risk, nutritional considerations and the patient's ability to engage in long-term follow-up. The broader lesson is that obesity and diabetes management should not be separated from surgical options when appropriate. STAMPEDE remains a landmark study demonstrating that surgery can achieve meaningful metabolic disease control rather than serving solely as a weight-reduction intervention.