How Does Gastric Bypass Work?

Do you have a lot of weight to lose and have tried everything? Are you thinking about getting gastric bypass surgery? Gastric bypass is a surgery that helps you to lose weight by changing how your stomach and small intestine handle your food intake. This surgery has been successful for many, so how does gastric bypass work?

Below, you will find information on the surgery and how it works. 

How Does Gastric Bypass Work?

What is Gastric Bypass Surgery?

Gastric bypass is a surgery that aids in weight loss. During the surgery, the doctor will make changes to your stomach and small intestine. This changes the way your stomach and intestine absorbs food. 

How does this type of bariatric surgery work?

When getting a gastric bypass, the doctor must perform two steps. These two steps include: 

  1. The first step is making your stomach smaller. The surgeon uses staples to divide your stomach into a small upper section and a larger bottom section. The top section is typically called the pouch. This is where the food you eat will go. The pouch is about the size of a walnut. 
  2. The second step is called the bypass. This is where the doctor connects a small part of your intestine to the small hole in your pouch. This will allow the food that you eat to travel from the pouch to your small intestine. 

Types of bariatric surgery

The surgery can be done in two ways: open surgery or laparoscopy. 

Open surgery: With open surgery, your doctor will make a large surgical cut to open your stomach. In the open surgery, the surgeon will work on your stomach, small intestine, and other organs while your belly is open. 

Laparoscopy: When a surgeon choose to do the surgery laparoscopically, they use a tiny camera called a laparoscope to do the surgery instead of cutting your entire belly open. Here is how it works.

  • The doctor makes four to six small cuts in your belly. 
  • The scope, camera, and instruments are inserted through these cuts. 
  • The camera is connected to a monitor in the operating room so that the surgeon can view the inside of your belly while doing the operation. 

The type of surgery you get will depend on various factors. You should always talk with your doctor about both options. 

Related: What is Roux En Y Gastric Bypass

How Does Gastric Bypass Work?

As stated above, gastric bypass aids in weight loss, but how exactly does this surgery do that? Gastric bypass works in the following ways: 

  • It restricts the amount of food that your stomach can hold. Since the pouch is only the size of a walnut, you can only hold about an ounce of food at a time. 
  • The surgery limits the amount of calories and nutrients your body can absorb. This is done because the small intestine is now hooked to only the pouch. 
  • Ultimately, it changes your gut hormones which helps you to feel fuller longer. 


Because it contributes to appetite suppression, you will see the reversal of obesity caused by metabolic syndrome. 

Advantages VS Disadvantages Of Gastric Bypass

Now that you know what gastric bypass is and how it works, it is important to weigh the odds. This surgery comes with both advantages and disadvantages. It is important to discuss them as well as any concerns with your doctor. Gastric bypass requires some huge dietary changes. You may want to read What to eat after Gastric Bypass Surgery

Advantages of Bariatric surgery

Some of the advantages of having this surgery include:

  • Many patients have a 60-80% excess weight loss making you lose weight in the short term. 
  • Data shows that most patients maintain more than 50% of their excess weight loss 20 years after the surgery. This means it has great long term results as well. 
  • It resolves obesity-related health problems

Related: 10 Health Benefits of Gastric Bypass Surgery

Disadvantages of gastric bypass

Like all procedures, there are things you will want to think about. Here are a few of the disadvantages to getting gastric bypass surgery: 

  • Taking aspirin or NSAIDS is not permitted after surgery. 
  • There is a slight risk of long-term complications.
  • You will need to take vitamins for life after the surgery. Otherwise it could lead to deficiencies in Vitamin B12, calcium, iron, folate, and other key nutrients. 

Additionally, you will have to change your diet after the surgery since your pouch will not be able to handle as much food. If you are worried about what you will eat, check out some of my other posts on what to eat after gastric bypass:

If you are considering this surgery, make sure you talk with your doctor about any questions or concerns. I hope you enjoyed learning about gastric bypass surgery!