Will I encounter digestive problems after gastric bypass?

The headlines may sound alarming: “Weight loss surgery tied to lasting digestive issues.” “After gastric bypass surgery, many experience eating difficulties.”  

The stories were in response to a December 2016 study published in the British Journal of Surgery that followed 249 patients who had laparoscopic Roux-en-Y gastric bypass. It found that two years after surgery, gastric bypass patients were far more likely to suffer from digestive problems, such as indigestion, diarrhea and flatulence, as well as an inability to tolerate certain foods than the control group, which did not have the surgery.  

However, these results aren’t that surprising. They simply highlight what we bariatric surgeons already know. Gastric bypass changes the way your body absorbs and processes food. Before surgery, patients spend months learning about the diet and lifestyle changes to which they must commit after surgery to mitigate the effects of how their bodies will change during surgery.  

When you have gastric bypass, the surgeon reduces the size of the stomach and reconnects the small intestine to the new stomach, bypassing the original stomach and several feet of the small intestine. This will make you feel full sooner, meaning you’ll eat less, but it also affects how food is processed and the amount of nutrients including vitamins and minerals that your body absorbs.  

Our patients are usually excited to follow their dietary recommendations to the letter before and immediately after the surgery. However, as they heal and time goes on, some of them fall off the wagon a little. They pay less attention to what they eat or try to push their diet a little further than they should. That’s usually when we begin to see gastrointestinal (GI) problems surface.  

Common side effects of weight loss surgery

Dumping syndrome

This is one of the most common complications patients face after bariatric surgery. Dumping syndrome occurs when food, especially sugar, moves too rapidly from the stomach into the small intestine. This can result in diarrhea, nausea and abdominal cramps.  

Dumping syndrome can be avoided by eating smaller meals and limiting foods high in sugar, as well as not rushing through your meal. We educate our patients about this syndrome, so they can recognize it. Patients often tell us that after it happens once, they learn pretty quickly what triggered it so it doesn’t happen again.  

Small bowel bacteria overgrowth

Everyone has a certain amount of bacteria living in their intestines. However, in rare cases, gastric bypass can cause bacteria to grow unchecked. This excess bacteria may eat up the nutrients your body needs and can cause bloating, cramping, gas and diarrhea.  

In severe cases, small bowel bacteria overgrowth can inhibit the body from properly absorbing nutrients, leading to malnutrition and vitamin and electrolyte deficiencies, such as anemia.  

Small bowel bacteria overgrowth usually can be successfully treated with antibiotics.  

Food intolerance

The study found that 71 percent of gastric bypass patients developed intolerance for fried foods, pastries and carbonated drinks. However, only 14 percent of those people said the intolerance was very bothersome.  

We stress to our patients the importance of avoiding and cutting back on foods high in fat and sugar because the body just doesn’t process them as well after surgery. You’ll still be able to eat these foods, just not as often and in moderation. This is good advice for anyone, not just people who have had weight loss surgery!  

We also see some patients who “develop” lactose intolerance after surgery. They most likely were mildly lactose intolerant before surgery, but the surgical changes caused it to surge. When they switch to lactose-free products, the problems go away.    

How to reduce complications after gastric bypass

In rare cases, complications from gastric bypass, such as small bowel bacteria overgrowth, can result in GI problems. But these problems usually are related to diet.  

Our patients go through on average six months of education before surgery to learn about the diet and lifestyle changes they’ll need to make. In the weeks and months after surgery, they go through a diet progression: from liquids only, to thicker liquids, to soft food, then to solid food.  

The most important thing you can do to prevent gastrointestinal problems is to follow the dietary guidelines. They may seem overwhelming at first, but you’ll likely find they become a part of your daily routine. And don’t rush to advance your diet or experiment with new foods before your dietitian gives you the OK.  

A few general tips:

  • Eat small portions.
  • Eat slowly and chew food thoroughly.
  • Limit foods high in sugar and fat.
  • Keep a journal documenting food and portions.
  • Drink water between meals to avoid dehydration. 

Following dietary guidelines is the best way to prevent gastrointestinal problems after #bariatricsurgery. via @MedStarWHC

We’ll test your vitamin and mineral levels six months after surgery, at a year, then yearly after that. This helps us catch potential nutritional deficiencies early and address them before they become a serious problem.  

If you experience persistent gastrointestinal or eating difficulties, see a doctor. We can check for surgical complications and discuss your dietary habits. This is where a food journal can come in handy. By examining what you’re eating and how much, we usually can pinpoint the culprit and solve the problem. Even if you do experience GI symptoms at some point, for the majority of my patients, the overall benefits of the surgery outweigh them.  

Bariatric surgery is not just about weight loss. It’s about improving your overall health and reducing the risks of life-threatening conditions caused by obesity, such as diabetes, hypertension and high cholesterol. By sticking to a healthy diet and lifestyle, you can reap the many health benefits of weight loss surgery and prevent or reduce potential complications.

Ivanesa Pardo, MD, FACS, is a board-certified general and bariatric surgeon at Medstar Washington Hospital Center. She is an active member of multiple professional societies, including the American Society for Metabolic and Bariatric Surgery (ASMBS) and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), where she sits on the Fundamentals of Laparoscopic Surgery (FLS) committee.

As a fellowship-trained bariatric surgeon, Dr. Pardo specializes in the surgical treatment of obesity through the use of minimally invasive techniques, such as laparoscopy and robotic surgery. She also sees patients for gallbladder disease, reflux disease and other gastrointestinal conditions, hernias, and solid organ surgery.