Diet, exercise, cognitive behavioral therapy and pharmacotherapy are some of the means of assisting patients to lose weight, with bariatric surgery being the most effective. Over the last two decades, the increased awareness of the systemic benefits of bariatric surgery, as well as the improved safety and the wider use of the laparoscopic approach, has made bariatric surgery flourish. In the United Kingdom, the adjustable gastric band (10%), vertical sleeve gastrectomy (37%) and Roux-en-Y gastric bypass (45%) are the three most common procedures. Obesity-associated mortality and co-morbidities such as type 2 diabetes, hypertension, dyslipidemia, obstructive sleep apnea, renal dysfunction and depression improve significantly with bariatric surgery. The mechanisms of weight loss extend beyond restriction and malabsorption and include changes in hunger and satiety, food preferences, and possibly energy expenditure. Despite its safety and efficacy, bariatric surgery is underutilized as less than 1% of adults with obesity receive it. In view of the evolution of obesity into a global threat, access to bariatric surgery should be increased, whilst developing safer and less invasive weight loss treatments.