Gastric bypass is surgery that 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 with less food.
The food you eat will no longer go into some parts of your stomach and small intestine that absorb food. Because of this, your body will not get all of the calories from the food you eat.

Gastric bypass is one of the most commonly performed types of bariatric surgery. Gastric bypass is done when diet and exercise haven’t worked or when you have serious health problems because of your weight.


Flatulence and abdominal cramps
Palpitations, rapid heartbeat and sweating
Dizziness or fainting


Your body mass index (BMI) is 40 or more (extreme obesity).
Your BMI is between 35 and 39.9 (obesity) and you have a serious weight-related health problem such as type 2 diabetes, high blood pressure, or severe sleep apnea. In some cases, you may be eligible for certain types of weight loss surgery if your BMI is between 30 and 34 and you have serious weight-related health problems.


There are several types of gastric bypass procedures. Your doctor will help you determine which type of surgery is best for you based on your medical history and weight loss goals.

Weight loss surgeries are generally divided into three categories:
Restrictive: Limits food intake by reducing the size of the stomach
Malabsorptive: Limits the consumption of food by bypassing parts of the small intestine
Restrictive and malabsorptive combination

Risk factor

As with any major surgery, gastric bypass surgery and other weight loss surgeries present potential health risks in the short and long term.

The risks associated with surgery are similar to those of abdominal surgery and can include:

Heavy bleeding
Side effects of anesthesia
Blood clots
Lung or breathing problems
Leaks in your gastrointestinal system
Long-term risks and complications of gastric bypass can include:

Intestinal obstruction
Dumping syndrome, which causes diarrhea, nausea, or vomiting
Low blood sugar level (hypoglycaemia)
Gastric perforation

When to see a doctor

Make an appointment with your doctor if you notice any signs or symptoms that are worrying you.