Hypoglycemia After WLS

Weight Regain With Symptoms of Hypoglycemia After WLS

September 2, 2020

Hypoglycemia After WLS & Weight Regain

Obesity is a progressive and expensive disease, with associated chronic, multisystemic clinical conditions such as diabetes, high blood pressure, obstructive sleep apnea, and cardiovascular disease. Bariatric surgery has been a well-established and durable long-term solution for obesity management.

Both the sleeve gastrectomy and gastric bypass surgery are commonly performed weight-loss procedures and have been effective in controlling glucose levels in a rapid and reliable manner. However, weight regain and symptoms of hypoglycemia are common complications after the surgery.

Weight regain often occurs due to a lack of dietary compliance, lack of exercise, and psychosocial factors. Hypoglycemia after weight loss surgery is recognized as a complication, and disruptive eating patterns adopted to avoid its symptoms may lead to weight regain. This article will discuss how to recognize the symptoms of hypoglycemia and manage and prevent weight regain.

Hypoglycemia After WLS

Hypoglycemia in post-bariatric surgery patients is defined as having blood glucose levels of < 60 mg %. Hypoglycemic symptoms include shakiness, palpitations, sweating, hunger, and anxiety.

Neuroglycopenic symptoms, caused by low levels of glucose in the blood go to the brain and nervous system, present with flushing, weakness, drowsiness, blurred vision, seizures, and loss of consciousness.(1)

Hypoglycemia is diagnosed when the patient exhibits these symptoms accompanied by low plasma glucose levels, both of which can be relieved by ingesting carbohydrates.(2)

Postprandial hypoglycemia is more prevalent in patients who undergo gastric bypass than sleeve gastrectomy.

Hypoglycemia after gastric bypass surgery is mediated by the rapid emptying of the gastric pouch into the small bowel, followed by an increase in insulin secretion.(3,4)

Dumping Syndrome

Dumping syndrome is a commonly recognized metabolic complication of weight loss surgery and is classified into early and late phases depending on the time of onset after a meal.

Early dumping syndrome develops within 15 minutes after eating and is characterized by abdominal pain, diarrhea, nausea, and excessive bowel sounds.

Late dumping syndrome occurs 1-2 hours after the ingestion of a meal and the symptoms are due to hypoglycemia. It usually occurs at the initial stages after surgery upon resumption of diet. It is often mild in nature, but some patients experience severe life-threatening hypoglycemia associated with seizures and loss of consciousness, which may result in motor vehicle accidents.

Post-bariatric surgery hypoglycemia (PBSH) is also known as late dumping syndrome, occurs one year after surgery and is predominantly associated with neuroglycopenic symptoms. The reported incidence in the literature of post-bariatric surgery hypoglycemia varies from 0.1% to 34%.(5,6,7)

Diagnosis is established by the presence of neuroglycopenic symptoms, normal fasting blood glucose, insulin, and C-peptide levels. A pattern of hyperglycemia within 30 minutes of a high-glucose meal, followed by significant hypoglycemia on continuous glucose monitoring, is highly suggestive of PBSH.

Maladaptive Eating

Maladaptive eating to mitigate the hypoglycemic symptoms causes weight regain, which is considered significant when it exceeds 10%. According to Varma et al,(7) more than 50% of individuals with weight regain of under 20% experience symptoms of Post-Bariatric Surgery Hypoglycemia (PBSH), and there is a decrease in the frequency of symptoms in those who gained the most weight. Insulin-induced low blood sugar, as in PBSH, enhances glucose uptake by tissues and stimulates the appetite with subsequent caloric intake to prevent symptoms of hypoglycemia.

The presence of PBSH symptoms, poor adherence to nutritional advice, and more time elapsed since surgery were associated with significant weight regain of more than 10%.(7)

Dietary modification is the most essential part of management, and it includes reducing the consumption of carbohydrates per meal, adding proteins and fats to balance the meal, and eating in small quantities.

Increasing the frequency of meals to 5-6 times per day will aid in effective digestion, along with substituting non-fructose base carbohydrates with fructose and avoiding foods with a high glycemic index.

Maintaining a food journal is an effective way to keep track of food intake and overeating. In the case where these methods are not effective, medical or surgical interventions can be implemented to reduce carbohydrate absorption.

What is Acarbose?

Acarbose is an antidiabetic medication which inhibits Alpha-glucosidase, an enzyme found in the lining of the intestines that functions by breaking down starch to glucose.(8) This will prevent starch breakdown to glucose and is effective in treating hypoglycemia after gastric bypass by preventing fluctuations in blood glucose levels.(9) Diazoxide, a potent blood pressure medication which inhibits insulin secretion, will increase blood glucose levels as well.(10)

Other medications that are used to treat dumping syndrome are octreotide,(11) glucagon and investigational drugs like Exendin 9-3.(11,12) For refractory post-gastric bypass hypoglycemia, the surgical options include placing a feeding tube in the remnant stomach, reversing the gastric bypass, or conversion of bypass to sleeve gastrectomy to maintain weight loss.

Post-bariatric surgery hypoglycemia is a well-recognized and serious complication that can cause weight regain due to maladaptive eating behavior.

Early recognition of symptoms and diagnosis is critical to successfully manage this condition and prevent life-threatening complications and weight regain. Patient education and awareness, in conjunction with a multidisciplinary team approach involving nutritionists and endocrinologists, are essential in this regard.


  1. Laferrere B, et al Effect of weight loss by gastric bypass surgery vs hypocaloric diet on glucose and incretin levels in patients with type 2 diabetes J Clini endocrinology and metabolism 2008 Jul;93(7)2479-85.
  2. Braghetto I et al Scintigraphic evaluation of gastric emptying in obese patients submitted to sleeve gastrectomy compared to normal subjects Obesity Surg 2009 Nov; 19(11):1515-1521
  3. Flegal KMKruszon-Moran Trends in Obesity among adult in the United States 2005-2014 JAMA 2016;315(21)2284-91
  4. Whipple AO Adenoma of islet cells with hyperinsulinism a review- Annals of Surgery1935
  5. Towler DA, Havlin CE Mechanism of awareness of hypoglycemia
  6. Sarwar H Chapman WH Hypoglycemia after RYGB the BOLD experience Obesity Surg 2014;24(7) 1120-4
  7. Lee CJ Risk of post-gastric bypass surgery hypoglycemia in non-diabetic individuals single-center experience Obesity 2016 Jun;24(6):1342-8
  8. Varma et al Weight regain in patients with symptoms of post-bariatric surgery hypoglycemia Surg Obes Relat Dis.2017 Oct:13(10):1728-1734
  9. Valderas D Acarbose improves hypoglycemia following gastric bypass without increasing Glucagon like peptide 1 levels; Obesity Surg 2012 Apr22(4): 582-6
  10. Spanakis E et al successful medical management of post-RYGB hyperinsulinemic hypoglycemia Obes Surg 2009 Sep; 19(9):1333-4,
  11. Rogers C Post gastrectomy nutrition Nutrition clinic Pract 2011;26:126
  12. Craig CM Subcutaneous exendin 9-39 effectively treats post-bariatric hypoglycemia //9 Diabetes 2016: 65 supplement 1
  13. Mulla C automatic event-based for prevention of post-bariatric hypoglycemia using mini dose of stable Glucagon Endocrine Rev 2017; 38 Issue 2 supplement
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Venkata kella


Venkata Kella, MD is a member of the bariatric team at NYU Winthrop Surgical Associates. Dr. Kella is a board-certified general surgeon with a specialization in minimally invasive / laparoscopic and robotic bariatric surgery. Dr. Kella passes on that knowledge to subsequent generations of surgeons as a clinical Assistant Professor at the NYU Department of Surgery.