What is weight loss surgery?

Weight loss surgery, sometimes called "bariatric surgery," is surgery to help you lose weight. It works by making you take in fewer calories and nutrients.

Who can have weight loss surgery?

Doctors use a measure called "body mass index," or BMI, to decide who is underweight, at a healthy weight, or overweight. Your BMI will tell you which category you are in based on your weight and height (figure 1).

Weight loss surgery is appropriate only if you have not been able to lose weight in other ways and if you:

• Have a BMI above 35

• Have a BMI above 30 and have a medical problem related to obesity, such as diabetes, heart disease, or high blood pressure

For people who are Southeastern Asian or Indian, weight loss surgery might be an option for people with a slightly lower BMI than the numbers above. That's because people in these groups are more likely to carry weight around their middle, which can raise the risk of health problems.

Are there different types of weight loss surgery?

Yes. There are many different types. The most common are (figure 2):

• Gastric bypass – Gastric bypass is short for "Roux-en-Y gastric bypass." It is sometimes called "RYGB." For this surgery, the doctor closes off part of the stomach, leaving only a small pouch for food. Then, they connect the stomach pouch to the middle part of the small intestine. This allows food to "bypass," or go around, part of the stomach and small intestine.

  There are other surgeries that are similar to gastric bypass in how they cause weight loss.

• Gastric sleeve – Gastric sleeve is a surgery that turns the stomach into something that looks like a sleeve. It is also called "sleeve gastrectomy." For this, the doctor removes a large portion of the stomach and leaves a narrow tube.

How is weight loss surgery done?

In the US, almost all gastric bypass and gastric sleeve procedures are done as "laparoscopic" surgery. For laparoscopic surgery, the surgeon makes a small cut (incision) and inserts a narrow tool that has a tiny camera on the end into the belly. This tool is called a "laparoscope." It lets surgeon see inside the belly without opening it up all of the way. Then, they can do the surgery using other tools that fit through small openings in the belly. These tools can be controlled from the outside.

How do the different procedures compare?

Each type of weight loss surgery is different, and each has different benefits and downsides.

• Gastric bypass leads to more weight loss and works the fastest, but it also comes with more risks. It can also cause problems in how your body absorbs nutrients. As a result, it can lead to "nutritional deficiencies," meaning that the body is missing important nutrients. This can sometimes make you sick. If you have gastric bypass, your doctor will monitor your nutrient levels afterward.

• Sleeve gastrectomy is less risky because it does not involve rerouting or cutting and reattaching the intestines. It is also less likely to cause problems with how you absorb nutrients.

Which surgery is best for me?

The decision about which type of surgery to have is important. Discuss your choices with your doctor.

If you have different options, ask the following questions:

• About how much weight can I expect to lose with each option?

• How long will it take me to lose the weight?

• What are the risks of each option for someone like me?

• What changes will I need to make to my diet and lifestyle with each option?

Whatever you decide, make sure that your surgeon is very experienced with weight loss surgery. Also, check with the staff at your treatment center or make sure that it is a certified "Center of Excellence." Those centers have a team of nurses and doctors who specialize in taking care of patients like you. If you are at all unsure about your decision, you can ask for an opinion from another doctor. Most hospitals that have experience with weight loss surgery offer patient education sessions. In these sessions, you can learn more about weight loss surgery and your options.

What are the benefits of weight loss surgery?

In addition to helping you lose weight, surgery can help improve or even get rid of certain health problems. These include:

• Diabetes

• High blood pressure

• High cholesterol

• Sleep apnea, a disorder that causes you to stop breathing for short amounts of time while you sleep

• Fatty liver disease

What are the risks of weight loss surgery?

It depends on:

• What type of weight loss surgery you have

• Whether your surgery is open or laparoscopic

• Your age and overall health

• How experienced your surgeon is

In general, the risks could include:

• Bleeding

• Infection inside the belly or in the incisions from surgery

• Leaks from the incisions on the stomach or intestine

• A blockage or tear in the intestines

• Problems with the heart or lungs, including blood clots

• Gallstones

• Nutritional problems

• Severe diarrhea

• Needing more surgery

As with any kind of surgery, it is possible for these procedures to lead to serious problems or even death. Death following weight loss surgery is very rare. But it's still important to talk to your doctor about all of the possible risks of each type of surgery.

Will I need to change the way I eat after weight loss surgery?

Yes. Work with a dietitian (food expert) to learn how to change your diet.

You will need to eat healthy foods that "work with" your surgery. For example, choose foods high in protein and low in fat and calories. You should also avoid liquid foods that are high in calories, such as ice cream. Being careful about what you eat will make you more likely to keep a healthy weight after surgery.

If you have weight loss surgery, you will need to avoid certain foods that could make you sick. You will also probably need to take special multivitamins with minerals. That's because weight loss surgery, especially gastric bypass, can make it hard for your body to get all of the nutrition it needs. You must take the vitamins for the rest of your life. Your body will always need them to stay healthy.

Images

figure 1: Your body mass index (BMI)

Find your height (in feet and inches) in the top row. Then, find your weight (in pounds) in the first column. Now, find where the column for your height and the row for your weight meet. That is your BMI. For example, if you are 5-feet-9-inches tall and you weigh 260 pounds, your BMI is 38.

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figure 2: Weight loss surgery

These drawings show how the most common weight loss surgeries work. Panel A shows a gastric bypass, and panel B shows a gastric sleeve.

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