reactive hypoglycemia after wls 3

Reactive Hypoglycemia After WLS: Causes, Symptoms & Nutrition Tips

October 30, 2017

Have you ever felt lightheaded, dizzy, shaky, sweaty, weak, tired or disoriented one to four hours after eating? Maybe you even fainted or lost consciousness. If so, you may have experienced reactive hypoglycemia, also known as late dumping syndrome or hyperinsulinemic hypoglycemia.

These are all just fancy ways of saying you had low blood sugar after eating. This happens when sugar quickly enters the intestine and then rapidly gets absorbed into the bloodstream. This causes the pancreas to over-react and release too much insulin, resulting in low blood sugar.

The brain uses sugar as fuel. That is why having a low blood sugar can cause some of the scary symptoms mentioned earlier. If you experience reactive hypoglycemia after weight loss surgery, you are not alone. Up to 34% of people have reported symptoms of reactive hypoglycemia at least one time in their life after gastric bypass and sleeve gastrectomy.  The same changes in gut hormones that help induce remission of diabetes after weight loss surgery may also cause some people’s pancreas to release too much insulin. However, there is good news! A few changes to your diet can help prevent episodes of reactive hypoglycemia.

10 Nutrition Tips To Prevent Reactive Hypoglycemia

Limit or avoid sugar and refined sources of carbohydrates. Refined sources of carbohydrate include sugar, juice and refined grains, like white rice, white pasta, white bread or pastries. These foods quickly spike your blood sugar, which then leads to hypoglycemia. When choosing a food, look at the “Nutrition Facts” label on the back of the package. Choose items that are low in sugar and high in fiber.

Check the ingredient list. If sugar or a refined grain is one of the first few ingredients, avoid it or limit the portion. Any flour or grain without the word “whole” in front of it is likely refined. Some common names for refined grains on the ingredient list are enriched wheat flour, unbleached wheat flour, wheat flour and rice flour.

Hidden names for sugar include any word ending in “ose” (sucrose dextrose, fructose, etc.), anything ending in syrup (corn syrup, brown rice syrup, maple syrup, etc.), and anything with the word “cane” in it (ex. evaporated cane juice). There are also a few “natural” sweeteners that are mostly sugar. These include honey, agave, molasses, fruit concentrate and coconut sugar. Small amounts of calorie-free sweeteners are fine and are not likely to cause reactive hypoglycemia. These include sucralose (Splenda©), aspartame (NutraSweet©), saccharin (Sweet’N Low©) and stevia.  Check out the table at the end of the article for alternatives to food with lots of sugar or refined grains.

Eat 5-6 small meals with less than 30g of carbohydrate per meal. To put this in perspective, a small piece of fruit, 1 cup of milk or 1/3 cup of brown rice has about 15g of carbohydrate. Eating smaller portions of carbohydrate foods will prevent your blood sugar from rapidly rising and falling. One study showed that eating 6 meals a day with less than 30g of carbohydrate per meal prevented episodes of reactive hypoglycemia by 85%.
Choose carbohydrate foods with soluble or viscous fiber. The soluble fiber found in beans, oats, barley and certain fruits and vegetables are vicious. This means the fiber has a thickening effect, which slows the digestion of carbohydrate. Foods with viscous fiber are known as “low glycemic index” carbohydrates because they don’t spike your blood sugar. Choose low glycemic index foods to help keep your blood sugar steady. You can check out more about the glycemic index, high and low glycemic foods.
Include a good source of protein at every meal. Protein helps keep you full and satisfied with smaller amounts of carbohydrate. It also tends to digest slower than carbohydrate, which may help keep your blood sugar steady. You don’t need to go too crazy on the protein. 10-30g of protein per meal or snack is plenty. Choose slower digesting protein from whole foods, like meat, poultry, fish, dairy, eggs, beans, and soy when possible.
Include a healthy source of fat at each meal. Moderate amounts of fat will keep you satisfied with smaller amounts of carbohydrate. Some sources of fat, like nuts and avocado, are also great sources of fiber. To keep your heart healthy, choose fats from plants and fish, limit animal fat and stay away from trans-fat in processed foods, vegetable shortening and stick margarine.
Wait at least 30 minutes after eating to drink. Fluid may push down on the food in your pouch. This may cause the food to empty faster into the intestine, thus resulting in a rapid rise and fall in blood sugar.
Relax, slow down and enjoy your meal. Chewing your food well and taking 30 minutes to finish a meal will help you eat less. This also prevents food from entering the intestine too quickly. Try not to eat while distracted. Eating in front of the TV, computer or mobile device often prevents people from realizing how fast they are eating. Instead, focus on the color, flavor, aroma, and texture of the food. Many people find they eat slower when using smaller plates and utensils.
Keep a food journal. Most people should track what they eat and drink after weight loss surgery, but this is even more important if you are having symptoms of low blood sugar. Writing down what you eat and how you feel will help you identify foods or portion sizes that make your symptoms worse or better. Popular mobile apps, like Baritastic© and MyFitnessPal©, can also help you see if you are meeting your carbohydrate, fiber, protein and fat goals.
If the previous tips didn’t work, try adding guar gum or pectin to meals. These types of fiber help thicken the digested food as it travels down the intestine. This slows everything down, resulting in a steady blood sugar. Several small studies have shown that 5g of guar gum or 15g of pectin with meals can improve symptoms of dumping syndrome.

Psyllium is a more commonly available fiber supplement that may have a similar effect, but it hasn’t been specifically tested for reactive hypoglycemia. It is important to note that many people find it impractical to add 5-15g of fiber to meals. Fiber powders and capsules are easier to take with liquids, but weight loss surgery patients should avoid drinking while eating. Additionally, some people may experience gas, bloating, diarrhea or abdominal discomfort with large amounts of fiber supplements. Remember to drink plenty of water throughout the day. Taking fiber supplements while dehydrated may cause constipation.

Keep in touch with your bariatric surgery program. They can customize a treatment plan that works specifically for you. If you are unable to keep in contact with your bariatric surgery program, seek out a licensed health care provider familiar with reactive hypoglycemia after weight loss surgery.

Carbohydrates: Refined and Alternatives

Refined Carbohydrate High Fiber Alternative Low Carb Alternative
White bread Sprouted whole grain flourless bread (ex. Ezekiel Bread©), toasted
100% whole wheat bread, toasted
Lettuce Wrap
Steamed collard green wrap
Flour Tortilla Whole wheat tortilla
Corn tortilla
Low carb tortilla
Lettuce wrap
White Rice Brown rice
Wild rice
Whole wheat couscous
Barley or faro
Riced cauliflower
Riced Broccoli
Riced carrot
Riced squash
Pasta Whole wheat pasta
Lentil pasta
Black or garbanzo bean pasta
Spaghetti Squash
Zucchini noodles
White flour or breading Whole wheat flour
Brown rice flour
Ground oats
Almond flour
Coconut flour
Parmesan cheese
Regular crackers, pretzels or chips Stone ground whole wheat crackers,
roasted chickpeas
Parmesan cheese crisps
Sliced cucumbers
Regular cereal, instant oatmeal or cream of wheat/rice Old fashioned or steel cut oats
Hot oat bran cereal
Whole wheat cream of wheat
Low sugar bran or whole grain cereal
Homemade granola made with only roasted nuts, seeds, spices, and calorie-free sweeteners
Baked or fried potato Boiled potato, chilled
(increases resistant starch)
Yam or sweet  potato
Roasted carrots
Cauliflower puree
Chayote squash
Regular sweets Whole fruit (not juice)
Pastries made with whole wheat flour or ground oats and calorie-free sweetener
Sugar-free Jell-O
Low-carb protein shake
Sugar-free meringue cookies
Baked goods made with almond flour and Calorie-free sweetener


Jason Holden has been a registered dietitian at Loma Linda University Health since 2009. He completed his bachelor’s degree in clinical nutrition at University of California, Davis in 2008 and his dietetic internship at Brigham & Women’s Hospital in 2009. After working at Loma Linda University Medical Center for several years, he went on to earn a master’s degree in nutrition education from Framingham State University in 2015.

Read more articles from Jason!