Dumping Syndrome: When is Negative a Positive

What is dumping syndrome?

Dumping syndrome is an unpleasant reaction that can occur after gastric bypass surgery in response to eating or drinking certain foods and beverages. Many view dumping syndrome as a benefit because it helps them modify behavior and change food choices, resulting in greater weight loss and better long-term maintenance of weight loss.

After gastric bypass surgery, the movement of food from the pouch to the small intestine may occur very quickly. This can trigger a cascade of physical reactions, referred to as dumping syndrome. Specific food and beverage components are more likely to cause dumping syndrome–added sugars top the list, followed by high fats and occasionally the sugar naturally occurring in dairy products.

Although unpleasant, dumping syndrome, along with hormonal changes that occur after gastric bypass surgery, puts you back in control of what you eat as sweets and high fat foods become less desirable. And sweets are everywhere! Some experts suggest that the type of concentrated sugar found in cakes, pies, cookies, ice cream, pop and other treats affects the pleasure center of the brain in a way similar to the drug cocaine. This can make it difficult for some to break their sugar habit

I have given up a lot of things I used to love, like soda, but the way I look and feel –it is totally worth it.

 –Gastric Bypass Patient Michael H.

Understanding Dumping Syndrome

Dumping syndrome is broken down into two categories, early and late, based upon the reactions going on inside the body. Consume something high in fat and you may encounter early dumping syndrome, but eat something high in added sugar and you may have to deal with both early and late dumping syndrome.

Early Dumping Syndrome

With gastric bypass surgery, food movement between the pouch and small intestine is no longer regulated by a sphincter muscle that opens and closes. Instead, stomach contents empty out via gravity through a small M & M sized opening, called a stoma. When foods with high concentrations of added sugar, fat and occasionally  lactose (milk sugar) enter the small intestine, the body releases water in an attempt to dilute them. In addition, hormones are released that impact blood pressure and speed the transit time through the intestine. These reactions result in symptoms that can include abdominal cramping, diarrhea, nausea, vomiting, sweating, flushing, light-headedness, and a rapid heart rate. Symptoms usually start within 60 minutes after eating and last about an hour.

Late Dumping Syndrome

Late dumping syndrome occurs after ingesting foods or beverages with too much added sugar. When the high sugar concentration reaches the small intestine, not only does early dumping syndrome occur but blood sugar is also impacted. The body quickly absorbs the sugar from the intestine causing the blood sugar level to rise. In response to this flood of sugar, the pancreas over-responds and releases too much insulin. The high insulin load causes the blood sugar level to drop quickly, resulting in low blood sugar (hypoglycemia) that can trigger fatigue, weakness, light-headedness, flushing, sweating, shakiness, dizziness, fainting, loss of concentration, feelings of hunger, and rapid heart rate.

Late dumping usually happens 1 to 3 hours after eating. The symptoms can be mild or severe and last for a short time or remain for several hours. Learning to make changes to food choices and eating behaviors will reduce the risk.

To Avoid Dumping Syndrome

The good news is that dumping syndrome can be avoided. A few small modifications to what and how you eat greatly reduces the risk of having dumping syndrome.

  • Avoid foods and beverages with more than 2 grams of added sugar.

Sugars are either naturally occurring or added to the foods and beverages we consume. It’s important to learn the difference because the body handles the sugars differently. Naturally occurring sugars are found in fresh fruits and vegetables and in dairy products.
These sugars are typically well tolerated and do not cause dumping syndrome.

Added sugars are sugars that we add to foods to make them taste sweeter. These are often “hidden” in many highly processed foods, but also found in expected places, such as soft drinks, ice cream, cakes, pies, and cookies. Consuming added sugars will result in dumping syndrome for most who have had gastric bypass.

To limit added sugars, the diet should be built on healthy unprocessed foods as much as possible. Select low-fat protein sources (lean meat/fish/poultry, low-fat dairy, beans), fresh vegetables, fresh fruits, and whole grains. Barix Clinics recommends that added sugars are limited to 2 grams or less per serving.

Do this by looking at the nutrition facts label on the package to see how much sugar is in a serving. Then check out the ingredient listing below. If the product has more than 2 grams of sugar per serving and you see an “added sugar” term within the first five ingredients listed, put it back. Soon, food labels will include the amount of added sugar right on the label, making it easy to see how much sugar is added and how much is natural.

How Added Sugar Hides on Food Labels 

Below is a list of added sugars: 

agave syrup, brown rice syrup, brown sugar, cane sugar, corn sweetener, corn syrup, dextrose, glucose, high-fructose corn syrup, honey, invert sugar, maltose, malt sugar, maple syrup, molasses, organic brown rice syrup, organic cane syrup, raw sugar, sorghum, sugar, syrup

  •  Avoid high fat and fried foods. 

High fat foods are very concentrated and may empty out of the pouch quickly, resulting in early dumping syndrome.

Limit high fat foods such as high fat dairy (including cheese, cream, butter, sour cream, high fat milk, and high fat cottage cheese), high fat meats (including bacon, sausage, bologna, prime rib, ribs, and others), gravy, salad dressing, mayonnaise, nuts (including nut butters), fried foods, many fast foods and highly processed foods. Eat these foods in limited amounts only.

  • Limit dairy if it causes symptoms.
    Lactose (milk sugar), found in dairy products, can cause gas, cramping, bloating and diarrhea. This intolerance of lactose occurs when the body produces insufficient amounts of the enzyme needed to help digest lactose. Many people experience lactose intolerance throughout their lives. Others find that after bariatric surgery they become lactose intolerant—sometimes this is temporary. Fortunately, you may not have to exclude all milk and milk products from your diet. Small amounts may be tolerated:
  • Add milk to prepared foods, such as casseroles, soups or baked goods. This may slow down digestion, helping the body to handle the lactose more easily.
  • Try small servings of milk.
  • Say cheese. More than half of the lactose is removed when cheese is made—lower fat options are best.
  • Look for cultured milk products, such as yogurt or buttermilk. The friendly bacteria help your body digest lactose.
  • Use FairLife milk which is both lactose free and has 60% more protein.
  • Try soy, rice milk or almond milk—just watch for added sugar.
  • Try Lactase treated milk or caplets to aid in dairy food digestion. These products can be found at local grocery stores or pharmacys.
  • Try Digestive Advantage for lactose intolerance to increase the body’s ability to digest lactose.
  • Don’t eat and drink together.
    Drinking fluids with food causes food to be forced quickly, rather than emptying gently, through the stoma into the small intestine. The body may respond to this concentrated load of nutrients introduced into the small intestine with dumping syndrome. The 5/30 rule is always a good one to follow–stop drinking 5 minutes before eating and don’t resume fluid intake until 30 minutes from the finish of a meal or snack.
  • Small protein-rich meals.
    Meal portions should be ¼ to 1 cup in size. Most meals should include a good source of protein. Pair simple carbs (fruits and grains) with protein or fat to limit blood sugar response. Eating six small protein-rich meals evens blood sugar levels which reduces that chance of dumping syndrome. Some examples of this being put into practice:

    • Include 1 teaspoon of peanut butter or string cheese with ½ of a small apple for a snack.
    • If spaghetti is on the menu, eat a very small (1/4 cup or less) portion of noodles and a larger portion of meat sauce (protein source).
    • Pair cottage cheese with peaches or pineapple.
    • Add fruit to protein smoothies (made with milk, low sugar yogurt and/or protein powder).


  •  Avoid extreme food and drink temperatures.

For some individuals, foods and beverages that are either very hot or very cold can empty into the intestine quickly, causing dumping syndrome. If you experience this, try moderate temperatures to see how your body responds.

How to Treat Dumping Syndrome 

Despite best intentions, if you’re starting to feel the effects of a wrong food choice—what do you do? If you can, lie down and wait for it to pass. Be sure to stay hydrated. If you consumed something high in added sugar, you may want to have something with natural sugar that will help restore blood sugar levels—a small glass of 100% fruit juice, ½ cup of unsweetened applesauce, or a glass of milk. Follow that with a small serving of protein to stabilize blood sugar levels.

The Bottom Line

Not all, but about 80% of gastric bypass patients will experience dumping syndrome if they don’t follow post-surgery eating guidelines. Changing eating habits is key to success with weight loss surgery. The built-in negative reinforcement of dumping syndrome may help to establish better food choices after surgery. Some Barix Clinics patients have found a negative really can be a positive.


About Deb Hart

Deb Hart is a Registered Dietitian Nutritionist. For the last 28 years, she has been helping bariatric surgery patients reach their health and weight goals. She teaches people how to set up a lifestyle that supports a healthy weight. Deb set up her own lifestyle to include lots of long walks with her furry family members, workout classes at her local wellness center, meal prepping, and finding new ways to enjoy foods without added sugar.
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