Gastric bypass is surgery that is done to help you lose weight. After the surgery, you will not be able to eat as much as before, and your body will not absorb all the calories from the food you eat.

See also: Laparoscopic gastric banding

This surgery helps you lose weight by changing how your stomach and small intestine handle the food you eat.

• After the surgery, your stomach will be smaller. You will feel full or satisfied with less food.
• The food you eat will no longer go into some parts of your stomach and small intestine that break down food. Because of this, your body will not absorb all the calories from the food you eat.

You will receive general anesthesia before this surgery. This will make you unconscious and unable to feel pain.

Gastric bypass can be done in 2 ways. In open surgery, your surgeon will make a large incision (cut) to open up your belly. Your surgeon will do the bypass by directly handling your stomach, small intestine, and other organs.

Another way to this surgery is to use a tiny camera, called a laparoscope, which is placed in your belly. This is called laparoscopy. In this surgery:

• First, your surgeon will make 4 to 6 small incisions in your belly.
• Then your surgeon will pass the laparoscope through one of these incisions. It will be connected to a video monitor in the operating room. Your surgeon will look at the monitor to see inside your belly.
• Your surgeon will use thin surgical instruments to do your bypass. These instruments will be inserted through the other incisions.
• You will probably stay in the hospital a shorter time and recover more quickly after laparoscopy, compared to open surgery. There are also fewer incision problems after this surgery. You will also have smaller scars and a lower risk of developing hernias after laparoscopic surgery.

Laparoscopy may not be safe for you if you:

• Have had abdominal surgery in the past. This is because you may have scar tissue from earlier surgery.
• Have severe heart and lung disease
• Weigh more than 350 pounds

There are 2 basic steps during both kinds of gastric bypass:

• The first step makes your stomach smaller. Your surgeon will use staples to divide your stomach into a small upper section and a larger bottom section. The top section of the stomach (called the pouch) is where the food you eat will go. This pouch is about the size of a walnut. It holds only about 1 ounce of food.
• The second step is the bypass. Your surgeon will connect a part of your small intestine, called the jejunum, to a small hole in your pouch. The jejunum is farther down from where your stomach normally attaches to your small intestine. Food you eat will now travel from the pouch into this new opening into your small intestine. When food travels this way, it bypasses the lower part of your stomach and the first part of your small intestine. Because of this, your body will absorb fewer calories.

This surgery takes about 4 hours.

This surgery may increase your risk for gallstones. Your doctor may recommend having a cholecystectomy (surgery to remove your gallbladder) before your bypass surgery.

Weight loss surgery may be an option if you are very obese and have not been able to lose weight through diet and exercise.

Gastric bypass surgery is not a "quick fix" for obesity. You must be committed to diet and exercise because you must continue dieting and exercising after the surgery. You may have complications from the surgery if you don’t. One problem some people have is throwing up if they eat more than their new small stomach can hold.

People who have this surgery should be mentally stable and not be dependent on alcohol or illegal drugs.

This procedure may be recommended for you if you have:

• A body mass index (BMI) of 40 or more. Someone with a BMI of 40 or more is at least 100 pounds over their recommended weight. A normal BMI is between 18.5 and 25.
• A BMI of 35 or more and a serious medical condition that might improve with weight loss. Some of these conditions are sleep apnea, type 2 diabetes, and heart disease.