The growing obesity epidemic with simultaneous escalation of the type 2 diabetes pandemic1 followed by the increasing number of bariatric and metabolic surgery2 further emphasize the demand and need for evidence-based assessment of all effective therapeutic approaches. The status of bariatric surgery as the most effective treatment in promoting substantial and sustainable weight loss with improvement of obesity-related comorbidities has been thoroughly established at short-term follow-up confirmed also by recently reported longer-term follow-up results.3-7 The beneficiary effects of bariatric surgery are mainly associated with weight reduction varying between the different procedures, but there is also mounting evidence indicating weight-independent effects of bariatric surgery on glucose homeostasis improvement beyond reduced food intake and body weight.8 However, body weight in terms of either weight loss or weight regain after bariatric surgery is a key outcome closely associated with the desired effects of bariatric or metabolic surgery on weight-related comorbidities. Both the increasing obesity health crisis and the associated increased demand for bariatric surgery highlight the importance of using uniform standardized definitions for weight loss and weight regain to provide optimal clinical guidance in the scientific literature, and this important issue has also been addressed by the American Society for Metabolic and Bariatric Surgery guidelines.9