Bariatric surgery is currently the most effective, long-term weight loss treatment for obesity, which results in reduced appetite and improved glycaemic regulation due to pronounced changes in the gut-brain axis. People seeking bariatric surgery often display high levels of disordered eating including compulsive eating triggered by stress, which can hinder weight-loss outcomes. Accumulating evidence suggests neuroendocrine alterations after bariatric surgery have favourable implications on reward-related food intake and taste preference changes. However, there is a paucity of research investigating the mechanistic underpinnings of reward-related eating after bariatric surgery. The aim of this study was to investigate the effect of bariatric surgery on reward related eating in a mouse model of vertical sleeve gastrectomy (VSG). Male and female C57BL/6 (n=74) mice were fed a high-fat diet before undergoing VSG or sham surgery. Prior to and after surgery, mice were tested for taste preferences and motivated behaviour towards palatable high-fat, high-sugar food in an operant conditioning chamber. Compared to sham mice, VSG mice had lower preference for sweet-tasting liquid and showed reduced motivation to work for a palatable reward after surgery. Another cohort of male and female mice will receive stereotaxic injections of the dopamine sensor (pAAV-hSyn-GRAB_DA1h) and fibre optic implant into the NAcc for fibre photometry dopamine signal recording during operant testing after VSG or sham surgery. Outcomes from this study will provide valuable insight into the neurobiological underpinnings of motivated eating behaviour in the context of bariatric surgery.