"There's more that we don't know than we do know": Unpacking uncertainty in bariatric surgery.

Bariatric surgery remains the "gold standard" treatment for obesity, according to the American College of Surgeons in 2025; however, while evidence shows that surgery can improve health and increase lifespan for many, most available data focus on short-term outcomes, and high-quality long-term research remains limited. Furthermore, patients and providers seemingly experience uncertainty regarding postoperative outcomes, frequently attributing suboptimal results to each other. To explore these uncertainties alongside broader elements of the surgical experience, we conducted semi-structured qualitative interviews with Canadian women who had received surgery at least 1 year prior and registered dietitians who currently or previously worked in bariatric surgery in Canada, using reflexive thematic analysis and thinking with theory to analyze data. We constructed three themes: (1) Surgical uncertainty and "misplaced" optimism; (2) Promise of certainty through pathologization; and (3) (Dis)honesty: Nondisclosure as uncertainty management. We argue that bariatric professionals must engage more transparently with uncertainty and evidentiary gaps to mitigate medical bias and provide more meaningful support to patients considering or living with the outcomes of the procedure.