The SM-BOSS randomized trial compared laparoscopic sleeve gastrectomy with Roux-en-Y gastric bypass in patients with severe obesity and followed them for five years. The study is valuable because it evaluates two widely used procedures within the same randomized framework rather than comparing separate patient populations. At five years, excess BMI loss was not significantly different between the two groups after adjustment for multiple comparisons. However, the procedures differed in their effect on gastro-oesophageal reflux. Reflux remission was more frequent after gastric bypass, while reflux symptoms worsened more often after sleeve gastrectomy. For surgeons, the practical message is that procedure choice should extend beyond weight-loss expectations. Baseline reflux symptoms, anatomical considerations, metabolic comorbidities, patient preferences and tolerance of long-term medication all contribute to deciding which operation is most appropriate. The study supports the view that sleeve gastrectomy and gastric bypass are both effective metabolic procedures, but they are not interchangeable. Their long-term physiological effects differ, especially around reflux. Shared decision-making is therefore essential. A patient with significant pre-existing reflux may have a different risk-benefit profile from a patient without reflux, even if both procedures appear broadly comparable in weight outcomes.