Abstract: Disclosed herein is a preoperative beverage that is formulated to be administered prior to an operation or surgical procedure. In particular, the preoperative beverage is a water-based beverage that is configured to provide a patient with calories and nutrients while also maintaining an osmolality that is suitable for preoperative use The preoperative beverage may have a pH greater than approximately 4.3, one or more carbohydrates to provide at least 200 calories, and an osmolality ranging between 250-300 mOsm to facilitate absorption in less than two hours. The preoperative beverage may also include one or more amino acids, as well as other nutritional supplements to facilitate the health and comfort of the patient before and after the operation or surgical procedure.