Reactive hypoglycemia post–gastric bypass

Reactive hypoglycemia (RH) may occur in patients one year or more after their bariatric surgery. Symptoms include shakiness, hunger, dizziness, cold sweats, confusion, anxiety and possible loss of consciousness. The further out from surgery you are, the more tuned in to your body and reactions to food you become.

Definition: RH is low blood sugar typically 1.5 to 3 hours following a meal. You probably will begin to recognize the signs and symptoms of low blood sugar. This is not related to a diabetes insulin reaction or even a former diagnosis of diabetes prior to surgery. RH is simply a side effect of gastric bypass that happens in a minority of patients. Pre-surgery excess weight leads to excess insulin production and insulin resistance. Additionally, the bypass surgery leads to certain hormone level increases that also increase insulin production. After surgery, patients become more sensitive to insulin, more rapidly clearing sugars from the blood stream and this is why low blood sugars, or RH, can occur.

Treatment: The way to treat symptoms is based on how severe they are. If it is time for the next meal, simply eat your normal meal. If you begin to feel like you are having a somewhat low blood sugar—a little weakness and shakiness—and it is not time for a meal, simply have a small carbohydrate (5g) choice with a small protein food, for example, five crackers with a string cheese, 1 lite Greek yogurt or a half piece of toast with peanut butter. On the other hand, if you have more serious symptoms such as nearly fainting and sweating profusely then it is time for a quick sugar hit. Have 4–6 ounces of regular juice or two glucose tablets as a rescue dose of glucose. Be cautious as this may lead to another low later on as your body processes this dose of sugar. If you are able, take a blood sugar reading with a glucometer. Aim for a reading between 70–100mg/dL.

Prevention: What can be done to reduce the likelihood of RH? Maintaining a constant blood sugar level throughout the day is the goal. Make sure you are eating balanced meals or snacks 3 to 4 times daily, spaced 3 to 4 hours apart. Include a lean protein and high-fiber grains, fruits and vegetables. Avoid sugary foods. The sweets will trigger the over-secretion of insulin, resulting in the blood sugar drop. Also, avoid alcohol. Alcohol inhibits blood sugar regulation in the liver and can contribute to low blood sugar. It also inhibits our decision making in general, leading to poor eating choices.

Pay attention to your body and treat low blood sugar before it gets too serious. When you eat a meal, have the protein food first, then the vegetable and eat the starch last. Typically, post-op patients eat a low-carb diet because it is best tolerated. If you find you are struggling with these issues, please contact Anne Bechtel, clinic dietitian, at or call the clinic at 952-442-7820.