After bariatric surgery, the new and very small stomach will often only hold about an ounce. For the first week after surgery, the patient will only be able to tolerate nutritious liquids. During the second week, pureed, high-protein foods such as cottage cheese, yogurt, and soft-cooked eggs may be added. After that, the patient may add one solid food at a time, such as well-cooked vegetables, fish, or chicken. It is crucial that the patient chew this more solid food very carefully, eating only a few tablespoonfuls at a sitting.

Post-surgery, patients should avoid high carbohydrate foods such as chips, pretzels, breads, rice, and pasta, as hey expand and can cause a potentially dangerous blockage. Lactose is also difficult to digest and may cause nausea, cramps, gas, or diarrhea. Patients who love milk should wait to reintroduce it until the third week post-procedure.

Protein is a vitally important nutrient, so a good rule of thumb is to eat protein first, then follow with fruits and vegetables. This will ensure that the daily minimum of 60 grams of protein is consumed. Patients may still need to take extra protein in the form of a liquid, powder, or protein bars. Additionally, patients will have a lifelong regimen of vitamin and mineral supplements post-surgery.

Failure to follow these dietary guidelines after bariatric surgery could lead to potentially serious complications. Early dumping syndrome, which is generally by overfilling the pouch, can cause minor symptoms such as nausea, cramps, diarrhea, and abdominal rumbling or more serious ones like low blood pressure, faintness, sweating, and anxiety. Late dumping syndrome, when food enters the intestine too rapidly, can cause hypoglycemia, sweating, rapid pulse, anxiety, and occasionally confusion.