The diet for Roux-en-Y gastric bypass surgery patients consists of liquids and soft foods for the first six weeks. Eat small frequent meals throughout the day and drink only in sips. In the first few weeks following surgery, gas and constipation is expected. Applesauce, pureed Prunes or over the counter medications are often recommended. A foul-smelling discharge at the incision site, unusual pain in the chest, legs or abdomen, temperature higher than 101 degrees or passage of dark stool should be reported to the physician's office. A bright red or dark brown liquid vomit requires an emergency room visit.