Gastric Bypass vs Duodenal Switch Surgery: Which One Is Best?

Obesity is an ever-increasing epidemic in the United States today with over 75% of the adult population weighing in as overweight or obese. Sometimes diet and exercise are not enough to help patients reach a healthy BMI level and doctors will recommend bariatric surgery.

Bariatric weight loss surgery is an effective tool that can facilitate substantial weight loss for obese patients.

The three standard bariatric procedures are

  • Gastric bypass, which has been around the longest;
  • Gastric sleeve is the surgical reduction of the patient’s stomach and is step one in both the gastric bypass and duodenal switch surgeries;
  • Duodenal switch offers the greatest weight loss potential but is also the most invasive.

The gastric sleeve has gained popularity in recent years because it is the fastest and easiest form of bariatric surgery. Today we are going to compare gastric bypass vs duodenal switch surgeries.


The First Step In Gastric Bypass or Duodenal Switch Surgery

Gastric bypass and duodenal switch surgeries are both multi-step procedures with the first step being surgically reducing the patient’s stomach size (often through what is known as gastric sleeve surgery).

During this first step, a surgeon cuts away and permanently removes about 75-80% of a patient’s stomach. The edges are then brought together and closed with surgical staples. This type of bariatric technique is known as “restrictive” because it limits the amount of food a patient’s stomach can hold.

Gastric bypass and duodenal switch surgery will both promote significant weight loss but there are differences between the two that will be a factor in which procedure your bariatric surgeon may choose for your circumstances.

A patient’s BMI will be considered when determining between gastric bypass vs duodenal switch surgery. Gastric bypass surgery is normally used for patients who have a BMI in the mid-40s to 50 and anyone above 50 is normally a candidate for the duodenal switch.

How Do Gastric Bypass and Duodenal Switch Differ?

An Overview Of Duodenal Switch Surgery

The medical term for this procedure is the biliopancreatic diversion with duodenal switch (BPD-DS) but is most often referred to as the duodenal switch for short.

The duodenal switch is the most restrictive, invasive, and malabsorptive, bariatric surgical procedure and is the least often performed. It is usually reserved to treat super obese individuals with higher BMI numbers.
How the duodenal switch works for weight loss

Duodenal switch surgery begins with a gastric sleeve procedure where the patient’s stomach is permanently made smaller by surgically removing a large portion. Next, two portions of the small intestine are re-routed to bypass approximately 3⁄4 of the digestive tract. When the ingested food skips most of the digestive process it limits the number of calories that can be absorbed and this is called the malabsorptive technique.

The Duodenal switch offers both reduced stomach capacity and the bypassing of most of the normal digestive processes which work together making both metabolic and hormonal changes that promote tremendous weight loss.

An Overview Of Gastric Bypass Surgery

Gastric bypass surgery (also called Roux-en-Y) has been around since the late 50s but the laparoscopic version we use today was first done in 1994. It has proven effective and is widely used by bariatric surgeons all over the world to help treat obesity.

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During gastric bypass surgery, the patient’s stomach is made smaller and the anatomy of the intestine is altered to change the path of food that is ingested. Approximately ⅔ of the digestive process is “bypassed” so the number of calories absorbed by the body is greatly reduced.

The smaller stomach helps patients feel full faster after eating smaller portions and the reduction in stomach size eliminates a large portion of the hunger-creating hormone ghrelin which is produced by the body to signal the brain that it is time to eat.

Gastric Bypass vs Duodenal Switch Comparison Chart

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the entire table

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Gastric Bypass Duodenal Switch
Suitable for Patients with this BMI 40-50 50+
Duration of Surgery 2 hours 4 hours
Excess Weight Loss Expectation 60-85% 75-90%
Malabsorption and Nutrition Stomach size is reduced by 75% Intestines rerouted once to skip approx ⅔ of the digestive process Stomach size is reduced by 75% Intestines are rerouted in 2 places to skip approx ¾ of the digestive process
  • Most often performed surgery;
  • Is considered Gold Standard;
  • High %EWL.
  • Higher %EWL;
  • Most effective for super obese patients;
  • Highest %EWL.
  • Moderate risk for complications;
  • Dumping Syndrome is common;
  • Not Reversible;
  • Some life-long nutritional supplementation is necessary;
  • Risk of gallstones.
  • Higher risk of Complications;
  • Not reversible;
  • Higher risk of long-term malnutrition results in the lifelong necessity for vitamin/mineral supplements;
  • Loose runny stinky stools, and gas;
  • Risk of gallstones;
  • Fewer doctors possess the expertise to perform this surgery.
Resolution of:

  • Type 2 diabetes
  • Hypertension
  • Sleep Apnea

  • 75%;
  • 45%;
  • 77%.

  • 95%;
  • 67%;
  • 92%.

Excess Weight Loss Expectations Gastric Bypass or Roux-en-Y vs Duodenal Switch

“Excess weight” refers to the difference between what the patient weighs now and how much they should ideally weigh (goal weight) If a patient currently weighs 300 pounds and their ideal or goal weight is 150, that patient has 150 lbs of excess weight. Excess weight loss (EWL) is calculated as a percentage of a patient’s excess body weight.

When comparing the duodenal switch vs Roux-en-Y for excess weight loss (EWL) potential the duodenal switch is more effective in helping patients achieve a higher percentage of EWL. On average, patients who undergo duodenal switch surgery normally lose between 75-80% of their excess body weight, and surgeons normally reserve this procedure for higher BMI patients.

Patients who undergo gastric bypass (Roux-en-Y) typically lose an average of 60-85% of their excess body weight which is higher than for a gastric sleeve procedure but not as much as the duodenal switch.

Duodenal Switch vs Gastric Bypass Nutrition and Malabsorption

Because both duodenal switch and gastric bypass surgeries involve alterations to the patient’s digestive system, these procedures put patients at a higher risk of complications due to malnutrition. The duodenal switch poses a higher risk because the alterations to the digestive system bypass a greater majority of the normal digestive process.

Gastric bypass patients experience dumping syndrome with more frequency than those who undergo the duodenal switch procedure (diarrhea and severe nausea with vomiting resulting from eating sugary or highly processed foods).

Patients who undergo either procedure will need to supplement their diet forever with certain vitamins and minerals and they will need to ensure they eat the correct foods and in the correct order. Patients who undergo gastric bypass surgery vs duodenal switch will need to ensure they supplement vitamins with a complete multivitamin, iron, Vitamin C, calcium, Vitamin D, Vitamin B12, etc.

More supplements are necessary after duodenal switch surgery including a multivitamin, calcium, iron, B-complex, fat-soluble vitamins A, D, E, and K, Copper, Zinc, etc. Most patients also need to take a daily probiotic.

Gastric Bypass vs Duodenal Switch For Overall Health Improvements

Losing weight has been proven to eliminate or reduce comorbidities related to obesity. Both these procedures are effective in improving patient health due to the drastic weight loss results they offer.

After undergoing significant weight loss, patients experienced a reduction or remission of type 2 diabetes with a 75% remission rate for individuals who underwent gastric bypass surgery and a 95% remission rate for duodenal switch patients.

The instances of sleep apnea, pain and mobility issues from their joints, rates of depression, and risks for many other serious health conditions were drastically reduced for patients who underwent both gastric bypass and duodenal switch surgeries. The type of surgery was less relevant and results were commiserated with the amount of weight lost. Duodenal switch surgery is performed on individuals who have more weight to lose and therefore also have more weight-related health issues making the percentages for improvement slightly higher.

Which Surgery Is Best For Me, Duodenal Switch vs Gastric Bypass?

Both gastric bypass and duodenal switch surgeries are effective in helping patients lose a tremendous amount of weight. Both also prompt hormonal and metabolic changes that help reduce hunger, slow digestion, and improve or eliminate weight-related health problems.

One of these surgeries may be right for you or perhaps an alternative to bariatric surgery would be best. A consultation with IBI Healthcare Institute will help determine the best weight loss program for your circumstances.

During your consultation, we will be able to get an understanding of your medical history, weight loss attempts, associated weight-related conditions, and your weight loss goals so we can tailor a successful personalized weight loss plan. Contact us today to learn more about weight loss options that would be right for you.