Hypoglycemia or low blood sugar after gastric bypass surgery can cause mild to severe symptoms. Some patients experience it during or shortly after meals, a condition called early dumping syndrome. Others experience late or delayed hypoglycemia several hours after meals. Hyperinsulinemic hypoglycemia, a rare complication, occurs one to two years after successful surgery and appears to be related to an increase in insulin production. Treatment varies according to the cause, frequency and severity of symptoms. See your doctor if you suspect you are experiencing hypoglycemia.
Patients lose weight rapidly after gastric bypass surgery because the procedure reduces the stomach to an egg-size pouch and reroutes the digestive system to block some calorie absorption. To facilitate and maintain weight loss, patients must make long-term dietary changes including increasing protein intake, avoiding sugary and fatty foods, and forgoing beverages containing caffeine, carbonation or alcohol.
Late Dumping Syndrome
Dumping syndrome, a long-term complication of gastric bypass surgery, occurs in about 10 to 15 percent of gastric bypass patients, according to a study published in 2006 by "Current Opinion in Endocrinology & Metabolism." Early dumping syndrome -- nausea, vomiting, gas, diarrhea and abdominal cramping during or shortly after a meal high in sugar -- results from undigested food emptying rapidly from the stomach into the intestine. Late dumping syndrome may occur up to two hours after eating, producing symptoms such as dizziness, weakness, sweating, palpitations and confusion related to hypoglycemia.
While symptoms of dumping syndrome can occur shortly after surgery, post-bypass hyperinsulinemic hypoglycemia begins a year or two after the procedure. Symptoms caused by an increase in insulin secretion may include tremors, palpitations, sweating, hunger or anxiety, as well as more severe symptoms of fatigue, confusion, seizures and loss of consciousness. Attacks generally occur within one to three hours after meals and increase in frequency and severity as time goes on.
Medical Nutrition Therapy
Treatment depends on the severity and frequency of the symptoms. The first step should be eating small, frequent meals to reduce insulin secretion. Eating complex carbohydrates such as vegetables and whole grains, as well as protein and fat at every meal, can slow the digestive process, reducing the symptoms of hypoglycemia. In severe cases, hospitalization and tube feedings can reverse the course of the condition according to a study published in 2010 by "The Journal of Clinical Endocrinology & Metabolism."
Life-threatening cases of delayed hypoglycemia have been treated surgically by reversing the gastric bypass or removing part of the pancreas to inhibit insulin production. Even after partial pancreatectomy, however, some patients continue to experience hypoglycemic symptoms, so even a complete pancreatectomy may be required. The syndrome may result from altered nutrition rather than pancreatic dysfunction, so gastrostomy feedings may be the better treatment.