Weight loss surgery patients require unique vitamin supplements before and after their procedures. Which supplements they need often depends on the type of surgery they had. Because bariatric surgery limits the amount of food a patient can eat and, in some cases, changes the way food is processed, weight loss surgery patients need to give added attention to getting enough bariatric vitaminsand nutrients — often through specially formulated supplements — to avoid certain surgical risks. In particular, after a malabsorptive operation, such as gastric bypass surgery, the patient is no longer able to absorb nutrients in the same way, even through generic supplement pills.