Although many patients have few problems after bariatric surgery, there is the potential for complications, both small and large, just as there is with any surgical procedure. Minor complications can include dietary intolerance, hair loss, dry skin, menstrual irregularities, or pain. Other complications that may occur include dumping, stenosis, a narrowing of the gastric pouchs outlet, vitamin or mineral deficiencies and anemia, gallstones, and vomiting caused by stretching the pouch.

More serious risks, ones that may need emergency attention, include bleeding, blood clots, infection, leakage of stomach acids, bowel obstructions, or hernia. Additional surgeries may be needed to correct any health problems that occur because of these complications. Of course, death is a risk as well, although the risk is less than one percent. Patients with a very high BMI and/or severe medical conditions are at the highest risk, but death can also occur in any patient.

Although significant weight loss occurs for nearly all bariatric surgery patients, regaining the weight is also a risk. Patients who do not maintain their lifestyle changes and eating behaviors may fall back into old habits and find that the scale is beginning to creep back up. Although significant weight gain after the initial weight loss is fairly infrequent, those who do experience it may have feelings of failure and depression.