BackgroundRamadan is considered to be the holiest month of the Islamic religion. Hundreds of millions of Muslims practice the commitments of Ramadan, which include the abstinence from eating and drinking during daylight hours. While there are exemptions to fasting for medical reasons, there is very limited guidance in terms of the safety of fasting in the post-operative period following bariatric surgery. ObjectivesTo assess outcomes and impact of fasting on patients who underwent bariatric surgery within the year leading up to Ramadan 2023. SettingCommunity Hospital health system MethodsRetrospective review of medical records and direct patient contact for 376 study participants ResultsOut of the 376 participants who underwent bariatric surgery in the year prior to Ramadan, only 8 patients (2.1%) reported they did not intend to fast during Ramadan. Patients who ended up having to break fasting were closer to their surgery date, at 4.3 months from surgery, than patients who were able to fast for the entire month of Ramadan, who were 5.1 months out from surgery. There was no difference between the number of patients needing to break fasting based on what type of bariatric surgery they had performed. The number of patients needing to go to the emergency department and receive intravenous fluids were small at 11 patients (2.9%) each, and were also closer to surgery than those not needing to go to the ED or receive IVF. Side effects experienced during Ramadan including abdominal pain, nausea/vomiting, and hypoglycemia were more common in patients that were closer to their surgery, notably within 4 months of their surgery date. Patients that lost weight during Ramadan were closer to their surgery date at 4.9 months from surgery compared to those who maintained or gained weight, who were 7.0 months out from surgery. ConclusionsThere are a limited number of studies examining the safety and patient outcomes in those who fast for religious purposes following bariatric surgery. In this study, 376 participants who were within one year of undergoing surgery were followed throughout the month of Ramadan. Patients closer to surgery were more likely to break fasting, present to the emergency department, and experience side effects. However, the overall rate of complications was low, suggesting that fasting in the setting of a religious tradition in the carefully chosen patient with counseling and supervision may be a safe option.