What is dumping syndrome after gastric bypass surgery?

Dumping syndrome after gastric bypass surgery is when food gets “dumped” directly from your stomach pouch into your small intestine without being digested. There are 2 types of dumping syndrome: early and late. Early dumping happens 10 to 30 minutes after a meal. Late dumping happens 1 to 3 hours after eating. Each has slightly different symptoms. 

What causes dumping syndrome after gastric bypass surgery?

Early dumping syndrome can occur because of the dense mass of food that gets dumped into your small intestine at an earlier stage of digestion. The intestines sense that this food mass is too concentrated, and release gut hormones. Your body reacts by shifting fluid circulating in your bloodstream to the inside of your intestine. As a result, your intestines become fuller and bloated. Diarrhea often occurs 30 to 60 minutes later. In addition, certain substances are released by your intestine that affect heart rate and often blood pressure, causing many of the symptoms of early dumping. This can lead to lightheadedness or even fainting.

Symptoms of late dumping happen because of a decrease in blood sugar level (reactive hypoglycemia). Reactive hypoglycemia is low blood sugar caused 1 to 3 hours after a large surge of insulin. You are more likely to have dumping syndrome if you eat a meal heavy in starches or sugars. The sugars can be either fructose or table sugar (sucrose). Insulin levels can increase to high levels, then lower your blood sugar too much.

Who is at risk for dumping syndrome after gastric bypass surgery?

Dumping syndrome can happen in 1 in 5 to 1 in 2 people who have had a part of their stomach removed for any reason. 

What are the symptoms of dumping syndrome after gastric bypass surgery?

Most people have early dumping symptoms. Typical early dumping symptoms can include: 

• Bloating

• Sweating

• Abdominal cramps and pain

• Nausea

• Facial flushing

• Stomach growling or rumbling

• An urge to lie down after the meal

• Heart palpitations and fast heartbeat

• Dizziness or fainting

• Diarrhea

• Feeling full after eating only a small amount of food 

About 1 in 4 people have late dumping symptoms. The symptoms of late dumping syndrome can include:

• Heart palpitations

• Sweating

• Hunger

• Confusion

• Fatigue

• Aggression

• Tremors

• Fainting

How is dumping syndrome after gastric bypass surgery diagnosed?

Your healthcare team will likely diagnose dumping syndrome based on your symptoms and when they occur. Tell him or her which foods or liquids give you symptoms. You may also need to have a glucose tolerance test or hydrogen breath test to help your healthcare provider diagnose you.

How is dumping syndrome after gastric bypass surgery treated?

The main treatment for dumping syndrome is changes in your diet. These include

• Don’t drink liquids until at least 30 minutes after a meal.

• Divide your daily calories into 6 small meals.

• Lie down for 30 minutes after a meal to help control the symptoms.

• Choose complex carbohydrates such as whole grains.

• Avoid foods high in simple carbohydrates, such as those made white flour or sugar.

• Add more protein and fat to your meals.

• Stop eating dairy foods, if they cause problems.

Another option is to slow gastric emptying by making your food thicker. Your healthcare provider may advise adding 15 grams of guar gum or pectin to each meal. But many people don’t tolerate these additions to their food.

If dietary changes don’t help, your healthcare provider may give you some slow-release prescription medicines. In rare cases, these may help, but they often don’t work. In severe cases of dumping syndrome, your healthcare provider may suggest tube feeding or corrective surgery.

Key points about dumping syndrome after gastric bypass surgery

• Dumping syndrome after gastric bypass surgery is when food gets “dumped” directly from your stomach pouch into your small intestine without being digested. There are 2 types of dumping syndrome: early and late.

• Early dumping syndrome can occur because of the dense mass of food that gets dumped into your small intestine at an earlier stage of digestion.

• The main treatment for dumping syndrome is changes to your diet.

• If the dietary changes don't help, you may need to take slow-release prescription medicine.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.