The worldwide incidence of obesity, defined as a BMI ≥ 30 kg/m2, has more than doubled during the past four decades. Bariatric/metabolic surgery provides the largest and most sustainable degree of weight loss. This review briefly summarises the emerging randomised evidence of the superiority of these procedures over conventional treatment, in achieving glycaemic control and inducing remission in patients with type 2 diabetes as well as the observational evidence suggesting improvements in the long-term risks of cardiovascular outcomes and mortality.