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Gastric Bypass Complications: Is Surgery Worth It?

Gastric Bypass Complications: Is Surgery Worth It?

Gastric bypass surgery currently is a second most common bariatric operation in the world. With morbid obesity and obesity-related illnesses on the rise, weight loss surgery is becoming a popular and effective treatment option. However, as with any surgical procedure, gastric bypass complications must be weighed against the benefits of surgery.

What Is Gastric Bypass Surgery?

Gastric bypass surgery is a procedure that changes the anatomy of the digestive tract to help with weight loss. Also called a Roux-en-Y, gastric bypass is a two-part operation. Firstly, the stomach is cut into a smaller pouch that limits the amount of food that you can eat. Secondly, bigger part of the stomach and part of the small intestine is bypassed to limit nutrient absorption.

Gastric bypass surgery is one of the most common bariatric procedures performed in the United States.

Who Qualifies For Gastric Bypass Surgery?

Individuals who qualify for gastric bypass surgery must meet one or more of the following criteria:

  • Body Mass Index (BMI) greater than or equal to 40, or greater than 100 pounds overweight.
  • BMI higher than or equal to 35 and have at least two diseases secondary to obesity. These diseases may include sleep apnea, type 2 diabetes, heart disease, hypertension, high cholesterol, obstructive sleep apnea, stroke, gout, and osteoarthritis.
  • Failure to lose weight through lifestyle and behavioral modification.

Individuals who seek gastric bypass surgery should know that this procedure requires a serious commitment to having a healthier lifestyle. Gastric bypass not only requires lifestyle changes before surgery, such as adhering to a strict pre-op diet, but it also requires dedication to exercise, portion control, and healthy dietary choices. Gastric bypass complications are significant and should be taken into consideration before surgery.

What Are Early Gastric Bypass Complications?

All surgeries pose some risks in the immediate post-operative period, gastric bypass complications are among some of the most significant. After gastric bypass surgery, you will likely be in the hospital for 1-3 days. These first few days are the most critical period for the complications. The most common early gastric bypass complications include:

  • Anesthesia-related complications such as breathing issues
  • Digestive contents leaking into the abdomen at surgical suture lines
  • Nausea and vomiting
  • Infection
  • Intestinal or stomach obstruction
  • Bleeding
  • Thromboembolism or blood clots

What Are Some Late Gastric Bypass Complications After Surgery?

It is important to note that there can be long term gastric bypass complications after surgery. Weight loss surgery has proven to be a successful weight loss tool for overweight individuals. However, it does require that you put in effort and care for the rest of your life to maintain the results from the procedure. The following is a list of late gastric bypass complications after surgery.

  • Low vitamin, iron, and calcium levels - Each patient must adhere to the supplement regime recommended by their provider. Because weight loss surgery patients eat a significantly reduced number of calories, they can quickly become deficient in essential nutrients. Similarly, certain foods may be particularly irritating following surgery, causing patients to avoid them. For example, dairy products can be rich in calcium, but patients may avoid them because of stomach upset. Each patient’s nutrient needs are unique. If you are considering gastric bypass, you must work with your provider and nutritionist to avoid vitamin deficiency or toxicity.
Weight loss surgery patients require vitamin and mineral supplementation throughout their life.
  • Protein deficiency - Due to limited food intake, gastric bypass surgery, patients can be deficient in protein. After surgery, your stomach can only hold about two tablespoons of food at one time. Therefore, the food you eat must be packed with protein. Ideally, gastric bypass surgery patients need to consume between 60-80 grams of protein daily. If you consume enough protein, you can ward off problems related to protein deficiency, including risk for infection, bone fracture, loss of muscle, and hair loss.
Proteins are the building blocks of cells. Eating a protein-rich diet is essential to maintaining your health after gastric bypass surgery. 
  • Dumping syndrome - Also known as rapid gastric emptying, bariatric dumping can be an unpleasant side effect of gastric bypass surgery. Because of the decreased size of the stomach, food contents can get rapidly “dumped” into the small intestine from the stomach. This rapid movement of food can cause diarrhea, nausea, vomiting, abdominal cramps, reactive hypoglycemia, rapid heart rate, and dizziness. While the symptoms are unpleasant and can impact a person’s quality of life, symptoms can be managed with diet and eating behaviors. Furthermore, most cases of bariatric dumping resolve 1-2 years after surgery.
  • Stenosis of the intestines - Stenosis (narrowing) may occur where the intestines were joined during gastric bypass surgery. If the narrowing between the joined areas of the intestine is severe, surgery may be indicated to repair the stenosis in order to prevent the blockage of food passing through the digestive tract.
  • Intestinal obstruction or hernia - After surgery, there is a risk that the small intestine may become blocked due to herniation or obstruction. It is important to seek medical help if you have abdominal cramping or pain, nausea/vomiting, abdominal swelling, loss of appetite, or loss of bowel function.
  • Failure to lose sufficient weight - Gastric bypass surgery is an effective method for weight loss. Most patients lose a significant amount of weight in the immediate post-operative period. However, as time passes, some patients find they are unable to reach their weight loss goals. This inability to lose enough weight can be due to eating and lifestyle behaviors that do not help with weight loss, such as poor diet and lack of exercise. If you find that you are unable to meet your weight loss goals following gastric bypass, meet with your provider to evaluate changes you can make in your lifestyle.
  • Regaining weight - Some patients find that they regain weight after they initially lose a significant amount of weight following surgery. The main culprits for regaining weight are snacking on high-calorie foods and not exercising.
Preventing weight gain and reaching your weight loss goals requires regular physical exercise after gastric bypass surgery.
  • Additional surgery - Because there are some long term complications of gastric bypass surgery, additional surgery may be indicated to correct these complications. For example, gastric bypass reversal can be performed if the results are undesirable or are medically necessary. Similarly, other bariatric procedures may be performed if the patient is unable to lose sufficient weight.  

It is important to note this list is not complete as each person has unique risks for complications based on their individual health. Furthermore, because of obesity-related conditions, there may be further gastric bypass surgery complications years later.

Is Gastric Bypass Surgery Worth It?

The long term benefits of gastric bypass surgery may outweigh the risks of the procedure. Patients who have had success with gastric bypass experience:

  • Long term weight loss - Rapid weight loss occurs in the immediate period following surgery. With a dedication to exercise and diet, patients can continue to lose weight until they reach a desirable, healthy weight.
  • Improved quality of life - This pertains to improvements in all areas of health, including physical, mental, and emotional health.
  • Cures or improvements to obesity-related diseases such as type 2 diabetes, sleep apnea, and hypertension.

As with any surgical procedure, there are complications. However, the risks of obesity and obesity-related diseases may outweigh gastric bypass complications. Each patient is unique. Therefore, meet with your provider to weigh the pros and cons of gastric bypass surgery with the risks of a lifetime struggle with weight.

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Julia Rae Walker, RN, BSN, BA


Julia is an experienced critical care nurse with a background in pediatric and adult patient populations. Her passion is helping patients maximize their quality of life.

Gintas Antanavicius, MD, FACS, FASMBS

Medical Reviewer

Dr. G is a co-founder of BariBuilder. A US-based expert surgeon with over 10 years of bariatric experience, he regularly publishes research in medical journals like SOARD, Obesity Surgery, etc.