Patient information: Weight loss surgery (The Basics)
Written by the doctors and editors at UpToDate
What is weight loss surgery?
— Weight loss surgery, sometimes called “bariatric surgery,” is a surgery to help you lose weight. It works by making your stomach smaller. Some types of surgery also change the path food takes through your gut so that 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 can have weight loss surgery. Your BMI will tell you whether your weight is normal for your height.
Weight loss surgery is appropriate only if you have not been able to lose weight through other means and if you:
●Have a BMI above 40 and have not responded to diet, exercise, or weight loss medicines; or
●Have a BMI above 35 and also have a medical problem related to obesity, such as diabetes, heart disease, or high blood pressure; or
●Have a BMI above 30, but only if you have certain medical conditions
Are there different types of weight loss surgery?
— Yes. There are many different types. The 3 most common are (figure 1):
●Gastric banding (gastric is another word for “stomach”) – For this surgery, the doctor wraps an adjustable plastic band around the top of your stomach, making a small pouch. The doctor can add or remove fluid through a button under your skin that is connected to the band with tubing. That way, the doctor can adjust how tight the band is. The tighter the band wraps around the stomach, the slower food passes from the pouch to the rest of the stomach.
●Gastric bypass – Gastric bypass is short for “Roux-en-Y gastric bypass,” and is sometimes called “RYGB.” For this surgery the doctor closes off part of the stomach, leaving only a small pouch for food. Then he or she connects the stomach pouch to the middle part of the small intestine. This allows food to “bypass” or reroute around a part of the stomach and small intestine.
●Gastric sleeve – Gastric sleeve, also known as “sleeve gastrectomy,” is a surgery that turns the stomach into something that looks like a sleeve. In other words, the doctor removes a large portion of the stomach and leaves a narrow tube.
Figure 1. Most common weight loss surgery options
These drawings show how the most common types of weight loss surgery reduce the size of the stomach.
How is the surgery done?
— All the different types of weight loss surgery can be done as “open” surgery or as “laparoscopic” surgery. For open surgery, the surgeon cuts open the belly and works on the organs directly. For laparoscopic surgery, the surgeon inserts a narrow tool that has a tiny camera on the end into the belly. This tool is called a “laparoscope.” It allows the surgeon to see inside the belly without opening it up all the way. Then the surgeon can do the surgery using other tools that fit through small openings in the belly and that can be controlled from the outside.
How do the different types of surgery compare?
— Each type of weight loss surgery is different, and each has different benefits and downsides (table 1).
Gastric banding is probably the simplest form of weight loss surgery. It involves the least amount of cutting and it can be adjusted or even undone. Gastric banding also leads to the least amount of overall weight loss. Plus, people who have gastric banding need to see the doctor often for adjustments, and some end up needing the band taken out.
Gastric bypass leads to the most weight loss and works the fastest, but it involves the most serious surgery with the highest risks. It can also cause problems in how your body absorbs nutrients. As a result it can lead to “nutritional deficiencies,” meaning that your 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 safer than gastric bypass because it does not involve rerouting or cutting and reattaching the intestines, and because it is less likely to cause problems with how your absorb nutrients. It might also be safer than the gastric banding because it does not involve any plastic materials that stay in your body.
How do I know 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 your surgeon is very experienced with weight loss surgery. Also, check with the staff at your treatment center or make sure 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 where you can learn more about weight loss surgery and the options you have.
What are the benefits of surgery?
— In addition to helping you lose weight, surgery can help improve or even get rid of certain health problems, including:
●Diabetes
●High blood pressure
●High cholesterol
●Sleep apnea, a disorder that causes you to stop breathing for short amounts of time while you sleep
●Gastroesophageal reflux disease, a condition that causes heartburn
What are the risks of surgery?
— The risks of surgery are different depending 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 wounds from surgery
●Leaks from the incisions on the stomach or intestine
●A blockage or tear in the intestines
●Problems with the heart or lungs
●Gallstones
●Nutritional problems
●Severe diarrhea
●The need for more surgery
Will I need to change the way I eat after surgery?
— Yes. Work with a nutritionist (a food expert) to learn how your diet should change.
You will need to eat healthy foods that “work with” your surgery. For example, you should 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. If you eat the wrong things, you could hurt your chances of losing weight.
If you have gastric bypass, you will need to avoid certain foods that could make you sick. Plus you will probably need to take special multivitamins with minerals. That’s because gastric bypass surgery can make it hard for your body to get all the nutrition it needs. You must keep taking the vitamins for the rest of your life. Your body will always need them to stay healthy.
©2016 UpToDate®
Comparison of weight loss surgeries
* Related diseases include diabetes, high blood pressure, sleep apnea, and high cholesterol.
¶ These include diseases such as difficult to control type II diabetes or metabolic syndrome (also called “insulin resistance syndrome” or “syndrome X”).
Δ Dumping syndrome causes nausea, shaking, sweating, diarrhea, and other symptoms soon after eating.