If you have tried the traditional way of diet and exercise to lose a significant amount of weight but have been unsuccessful in achieving any results, you may need a strong form of medical intervention like bariatric surgery. Gastric bypass and duodenal switch are two of the most effective forms of weight loss surgery performed today but many people are confused about the differences between duodenal switch vs. gastric bypass.
In this article we will look at the similarities and differences between gastric bypass and duodenal switch surgery, what they each involve, what you can expect from each, and we will also answer some frequently asked questions about duodenal switch vs. gastric bypass surgery.
How Do You Qualify for Duodenal Switch vs. Gastric Bypass?
The qualifications to undergo gastric bypass and duodenal switch surgery are similar, but they are not exactly the same.
Both surgeries require that:
- Patients must meet certain basic criteria, including having a BMI of at least 35 and suffering from conditions that are linked to their weight, like high blood pressure or type 2 diabetes.
- The patient has made previous attempts at losing weight using diet and exercise.
- The individual undergoes a psychological evaluation.
- The patient understands and is dedicated to making the lifelong commitment to lifestyle and dietary changes, including taking supplements, that will be needed for them to be successful and maintain their results.
- They are in good health and can tolerate undergoing surgery.
- They have no active substance abuse issues.
BMI Requirements for Duodenal Switch vs. Gastric Bypass
The body mass index (BMI) requirements for these two surgeries differ slightly
Gastric Bypass
This surgery is normally recommended for people who have a BMI of 40 or more, or a BMI of 35 or more plus an obesity-related health problem. Gastric bypass is the next step after gastric sleeve and uses both restrictive and malabsorptive techniques to limit the number of calories your body absorbs and uses.
Duodenal Switch
The biliopancreatic diversion with duodenal switch (BPD-DS), or more commonly called, the duodenal switch, is the most restrictive, invasive, and malabsorptive bariatric surgery and is the least often performed. It is usually used for patients who have a higher BMI, like 50 or higher, and is often considered the best option for patients suffering from super obesity because it provides the largest potential for weight loss. This bariatric surgery also requires the highest level of lifelong commitment to adhering to a strict dietary plan, which includes supplements to ensure you do not develop serious deficiencies.
How Do These Bariatric Surgeries Work
How Gastric Bypass Works
Gastric bypass surgery, if more formally called Roux-en-Y gastric bypass, with the meaning coming from a French term meaning “in the shape of a Y,” which describes the shape your digestive system is arranged into during the surgery.
During the procedure, the surgeon divides your stomach into two sections and creates a small pouch about the size of an egg from the upper portion, and the lower portion is bypassed and is no longer used to store or digest food. The new tiny pouch will only hold a very tiny amount of food, so you will feel full much more quickly, and after only eating a very small amount.
Next, the new stomach pouch is attached directly to your small intestine to make a shortcut that skips most of your stomach and part of your small intestine during digestion. The surgery is most often performed laparoscopically and usually takes between two and three hours. Gastric Bypass surgery prevents your body from absorbing all the calories you eat, significantly reduces fat absorption, and can lead to significant weight loss.
How Duodenal Switch Works
Duodenal switch surgery is much more complicated and is like a combination of gastric sleeve and gastric bypass surgery, and takes between three and four hours to perform.
The surgeon first removes about 80% of your stomach and manipulates the remainder into a much smaller tube-like shape. Then your small intestine is divided into two different parts, with about two-thirds of it arranged so the food you eat will bypass that portion altogether, and leaves just a few feet of intestine where the food mixes with the digestive enzymes so your body is only able to absorb a limited number of calories and nutrients.
Your significantly smaller stomach can only hold a tiny amount of food at the same time, and the portion that was removed also eliminates a large amount of the tissue that produces and releases the hunger hormones, which greatly reduces your appetite and food cravings.
Duodenal switch surgery cuts down the amount of fat your body absorbs by around 70% and results in greater weight loss than gastric bypass.
Main Differences Between Duodenal Switch vs Gastric Bypass:
When comparing duodenal switch vs. gastric bypass, there are many notable differences.
| Gastric Bypass | Duodenal Switch | |
|---|---|---|
| Average Weight Lost After Surgery | About 50 to 80 percent of excess weight lost in the first 12 to 18 months | About 80 to 85 percent of excess weight lost, with even more long term |
| Surgery Duration | Around 2 hours | Between 3 and 4 hours |
| BMI Range | Normally qualify with a BMI between 40 and 49 | Recommended, in most cases for individuals with a BMI of 50+ |
| Stomach Size After Surgery | Leaves you with a very small stomach pouch that limits your meal size | Reduces the size of your stomach but not as much as with gastric bypass, so you can eat larger meals. Weight loss is greater due to how much of the small intestine is bypassed |
| Calorie and Nutrient Absorption | Reduced absorption | Absorption is reduced much more due to a longer intestinal bypass |
| Risk of Nutrient Deficiencies | It is moderate, but it is manageable with supplements | The risk is much higher and requires following very strict lifelong use of supplemental vitamins and nutrients |
| Dumping Syndrome | The pylorus valve is bypassed, which acts like a small gate that controls how fast food leaves your stomach. Without this valve, dumping syndrome can and does occur after eating certain foods and may cause nausea, cramping, and diarrhea | Does not occur because the pylorus valve is not bypassed, which prevents food from emptying too fast into the small intestine |
| Impact on Diabetes and Blood Sugar | Strong improvement for many patients | Around a 90 percent remission rate, and is often more effective than gastric bypass |
| Overall Weight Loss Success | Very effective for many patients | Often produces the greatest and most sustainable weight loss |
Modified Duodenal Switch vs Gastric Bypass
Another type of duodenal switch surgery was created to cut down on surgical time and reduce the complexity of the procedure. The modified duodenal switch is called a single anastomosis duodeno-Ileal bypass with sleeve gastrectomy (SADI-S), which is a variation that makes the surgery faster and easier to perform. Instead of splitting the intestine into two separate paths that later reconnect, the surgeon creates one direct connection between the stomach and the lower part of the small intestine.
The SADI-S surgery takes less time to perform, reduces potential risks, and still offers excellent weight loss potential. It is a great middle ground option for people who need more help than a gastric bypass can give them, but they do not want to undergo the complex traditional duodenal switch.
How Do I Choose Between Gastric Bypass vs. Duodenal Switch Surgery?
The best way to choose the bariatric surgery that fits your needs and circumstances is to work with an expert bariatric surgeon like Brian Sung, M.D., and the team at Newvue in Bellevue, WA. They offer both surgical and medical weight loss options and will help guide you in choosing the best option to help you reach your goals.
The Newvue team will take the time to understand your medical history, current health, long-term goals, and lifestyle so they can create a customized plan that is right for you.
Both gastric bypass and duodenal switch can help you lose a substantial amount of weight that can improve metabolic and mobility issues like type 2 diabetes, high blood pressure, joint pain, etc. Our bariatric program also offers ongoing support before and after surgery, so you will be equipped with the knowledge, tools, and strategies that will help you achieve sustainable weight loss and improve your quality of life.
If you are ready to take the next step and learn about all the options available to you to help you lose weight, set up a consultation today!
Frequently Asked Questions
Can You Have Duodenal Switch After Gastric Bypass?
Yes, you can have a duodenal switch after a gastric bypass. This is called a gastric bypass conversion to duodenal switch, and it is sometimes recommended for individuals who did not lose enough weight or who regained weight after their initial gastric bypass surgery.
What Are the Top 5 Duodenal Switch vs. Gastric Bypass Pros and Cons?
Gastric Bypass
- Helps most people lose between 50 and 80% of their excess weight.
- Has been performed for decades, so typical results are well documented and studied.
- It can improve or even resolve issues like diabetes, high blood pressure, and other weight-related conditions.
- You may experience dumping syndrome, where food moves too fast through the stomach.
- Requires taking vitamins and minerals for life to stay healthy.
Duodenal Switch
- Offers the most weight loss potential of around 80–85% of excess weight.
- It can dramatically improve blood sugar control and help manage or reverse diabetes.
- Leaves a larger stomach than bypass, so you can eat slightly bigger meals.
- Risk is higher for experiencing vitamin and mineral deficiencies and requires strict supplementation of vital nutrients.
- The surgery is more complex and requires a longer recovery time.
What Is the Biggest Difference Between Gastric Bypass and Duodenal Switch?
The biggest difference between gastric bypass and duodenal switch is how much weight loss and nutrient absorption each one of these surgeries provides.
Gastric bypass significantly reduces your stomach size and then bypasses part of the small intestine, which cuts down on the amount of calories your body can ingest and absorb.
Duodenal switch removes more of the small intestine, which can lead to greater and longer-lasting weight loss but also requires stricter lifelong vitamin and mineral supplementation.
