Dumping syndrome happens when food moves too quickly from your stomach into the first part of your small intestine (duodenum) after you eat. This causes symptoms like cramps and diarrhea within a few minutes to a few hours after you’ve eaten. You can get dumping syndrome after you have surgery to remove part or all of your stomach, or if you have stomach bypass surgery for weight loss.

There are two types of dumping syndrome. The types are based on when your symptoms start:

  • Early dumping syndrome. This happens 10-30 minutes after you eat. About 75 percent of people with dumping syndrome have this type.
  • Late dumping syndrome. This happens 1-3 hours after you eat. About 25 percent of people with dumping syndrome have this type.

Each type of dumping syndrome has different symptoms. Some people have both early and late dumping syndrome.

Early symptoms of dumping syndrome include nausea, vomiting, abdominal cramping, and diarrhea. These symptoms usually start 10 to 30 minutes after you eat.

Other early symptoms include:

  • bloating or feeling uncomfortably full
  • flushing of the face
  • sweating
  • dizziness
  • fast heart rate

Late symptoms appear one to three hours after you eat. They’re caused by low blood sugar and can include:

  • dizziness
  • weakness
  • sweating
  • hunger
  • fast heart rate
  • fatigue
  • confusion
  • shaking

You might have both early and late symptoms.

Typically when you eat, food moves from your stomach into your intestines over several hours. In the intestines, nutrients from food are absorbed and digestive juices break down the food even more.

With dumping syndrome, food moves too quickly from your stomach into your intestine.

  • Early dumping syndrome happens when the sudden influx of food into your intestine causes a lot of fluid to move from your bloodstream into your intestine as well. This extra fluid causes diarrhea and bloating. Your intestines also release substances that speed your heart rate and lower your blood pressure. This leads to symptoms like a fast heart rate and dizziness.
  • Late dumping syndrome happens because of an increase in starches and sugars in your intestines. At first, the extra sugar causes your blood sugar level to rise. Your pancreas then releases the hormone insulin to move sugar (glucose) from your blood into your cells. This extra rise in insulin causes your blood sugar to drop too low. Low blood sugar is called hypoglycemia.

Surgery that reduces the size of your stomach or that bypasses your stomach causes dumping syndrome. After surgery, food moves from your stomach into your small intestine more quickly than usual. Surgery that affects the way your stomach empties food can also cause this condition.

Types of surgery that can cause dumping syndrome include:

  • Gastrectomy. This surgery removes part or all of your stomach.
  • Gastric bypass (Roux-en-Y). This procedure creates a small pouch from your stomach to prevent you from eating too much. The pouch is then connected to your small intestine.
  • Esophagectomy. This surgery removes part or all of your esophagus. It’s done to treat esophageal cancer or damage to the stomach.

You may be able to relieve symptoms of dumping syndrome by making a few changes to your diet:

  • Eat five to six smaller meals throughout the day instead of three big meals.
  • Avoid or limit sugary foods like soda, candy, and baked goods.
  • Eat more protein from foods like chicken, fish, peanut butter, and tofu.
  • Get more fiber in your diet. Switch from simple carbohydrates like white bread and pasta to whole grains like oatmeal and whole wheat. You can also take fiber supplements. The extra fiber will help sugar and other carbohydrates get absorbed more slowly in your intestines.
  • Don’t drink fluids within 30 minutes before or after meals.
  • Chew your food completely before you swallow to make it easier to digest.
  • Add pectin or guar gum to your food to thicken it. This will slow the rate at which food moves from your stomach to your intestine.

Ask your doctor whether you need a nutritional supplement. Dumping syndrome can affect your body’s ability to absorb nutrients from food.

For more severe dumping syndrome, your doctor can prescribe octreotide (Sandostatin). This drug changes how your digestive tract works, slowing down the emptying of your stomach into your intestine. It also blocks the release of insulin. You can take this drug as an injection under your skin, an injection into your hip or arm muscle, or intravenously. Some side effects of this drug include changes in blood sugar levels, nausea, pain where you get the injection, and foul-smelling stool.

If none of these treatments help, you can have surgery to reverse gastric bypass or fix the opening from your stomach to your small intestine (pylorus).

Dumping syndrome is a complication of stomach bypass or stomach reduction surgery. Other complications related to this surgery include:

  • poor nutrient absorption
  • weakened bones, called osteoporosis, from poor calcium absorption
  • anemia, or a low red blood cell count, from poor absorption of vitamins or iron

Early dumping syndrome often gets better without treatment in a few months. Dietary changes and medicine may help. If dumping syndrome doesn’t improve, surgery many be needed to relieve the problem.