You are currently viewing How is bariatric surgery performed? Types, advantages and risks

How is bariatric surgery performed? Types, advantages and risks

Bariatric surgery is a surgical procedure applied to obese people who cannot lose weight by means of diet and exercise and do not have hormonal problems. The purpose of this surgery, is to limit food intake by reducing the stomach and/or reducing the absorption of nutrients by bypassing the intestines. Surgery is performed by either open or laparoscopic surgery. Today, the most commonly used types are sleeve gastrectomy and gastric banding. A shrinking stomach gives the patient a feeling of satiety, allowing them to eat less and to lose weight safely and to reach ideal weight over time. It also treats many ailments such as obesity-induced type 2 diabetes, high blood pressure. However, it is a procedure that must be taken seriously and should not be performed without the examination and final recommendation of a team of specialist doctors.

What is bariatric surgery?

It is an extremely serious surgical intervention that modifies the digestive system, limiting food intake or reducing nutrient absorption. Bariatric surgery is also called as slimming surgery. It is a comprehensive surgery, which in some cases can cause serious risks such as perforation of stomach, ulcers, leakage from the rest of stomach into abdominal cavity. Therefore, the patient is kept under strict follow-up for a long time after surgery. The success of the operation is important for the patient to follow the doctor’s instructions. (1)

Why is bariatric surgery done?

It is used to help people with morbid obesity to lose weight and to treat obesity-related health problems: (2)

  • Reflux
  • Heart disease
  • Hypertension
  • Severe sleep apnea
  • Type 2 diabetes
  • Stroke

What is obesity?

Obesity is the accumulation of abnormal fat in the body at a concentration that would impair health. Whether a person is obese is determined by body mass index. Body mass index (BMI) is a ratio of weight to height. The obesity classification according to this measure is as follows:

  1. 1st category obesity: 30-35 (BMI)
  2. 2nd category obesity: 35-40 (BMI)
  3. 3rd category obesity: 40 and over (BMI)

Who is a candidate for bariatric surgery?

It is performed if the excess weight is not based on a hormonal cause:

  • For overweight (morbidly obese) people with a body mass index greater than 40
  • For patients with body mass index between 35-40 and severe health problems due to overweight such as type 2 diabetes, high blood pressure, heart disease, severe sleep apnea
  • In other cases, it may be applied to patients with body mass index 30-34 and weight-related health problems.

The age range of bariatric surgery is 18-65. Adolescents under the age of 18 may have surgery with parental consent if they have obesity related disorders. The decision of surgery is taken considering the general health status and the problems of overweight people over 65 years of age. (2)

Who benefits from bariatric surgery?

Having a bariatric surgery to lose weight is a serious decision. Surgery is only applied after to accelerate the weight loss process such as diet and exercise. For this reason, people who are considered suitable for slimming surgery should be willing and determined to make permanent changes in order to maintain a healthier lifestyle.

How is bariatric surgery decided?

Gastric surgeries cannot be applied to all people with obesity. First, it is necessary to determine whether the patient is physically and psychologically ready for this operation and the subsequent process.

Approval to the surgery is given only according to the result of consultation of the surgeon who examined the patient and the specialists of endocrinology, internal medicine, psychiatry-psychology, anesthesia and reanimation. Cardiology, chest diseases, physical therapists can also be consulted.

Types of bariatric surgery

Sleeve gastrectomy

This surgery is the most preferred type of gastric surgery today and is performed by taking out about 80% of the stomach. The remaining stomach is a tubular sac resembling a banana. (1)


  • It restricts the amount of food the stomach can hold.
  • Comparative studies have shown that it is as effective as gastric bypass in long-term weight loss.
  • It increases the sensation of satiety by causing positive changes in intestinal hormones.
  • Hospitalization is usually sufficient for approximately 2 days.


  • It is an irreversible procedure.
  • It has the potential for vitamin/mineral deficiencies in a long time.
  • The risk of complications is higher than the adjustable gastric band.

Gastric bypass

Gastric bypass consists of two stages. First, the upper part of the stomach is separated from rest to form a small gastric sac with a volume of about 30 milliliters. The first part of small intestine is then cut and lower end of divided small intestine is opened and connected to the newly formed stomach sac. (3)

The process is completed by connecting upper portion of small intestine, which was cut, to the further small intestine. The food consumed after the operation passes by most of the stomach and upper part of the small intestine, so that the body absorbs less calories.


  • Provides serious weight loss (60-80%) in the long term.
  • Limits the amount of food consumed.
  • It can create conditions that increase energy expenditure.
  • Produces positive changes in intestinal hormones that reduce appetite and increase satiety.


  • Because it is a more complex procedure than other stomach reduction operations, serious complications may occur.
  • In the long term, it may cause vitamin B12, B9 (folate) vitamins, iron, calcium and mineral deficiencies.
  • Longer hospital stay may be necessary.
  • It requires compliance with diet recommendations, lifelong vitamin/mineral supplementation and patient follow-up.

Adjustable gastric band

With this surgery, an inflatable band like a balloon is placed around the upper part of the stomach to form a small gastric sac. A narrow passageway is left between the remaining stomach and that gastric sac. The solution is then injected to a port from outside placed under the skin of the abdomen to inflate the band and adjust the passage of the food.

Food is digested and absorbed as in other times. A number of follow-up visits are required to adjust the size of the band opening after surgery. (4)


  • It reduces the amount of food the stomach can take.
  • It causes weight loss of about 40-50%.
  • The tape can be adjusted or removed if necessary.
  • It does not include cutting the stomach and redirecting the intestines.
  • It requires a hospital stay of less than 24 hours.
  • The risk of vitamin/mineral deficiency is very low.
  • It has the lowest complication rate in bariatric surgery types.


  • Slower weight loss than other surgical procedures
  • Inserting a foreign device into the body and having a risk of damage to the stomach
  • The necessity of strict adherence to postoperative diet and follow-up visits

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

It is a rarely performed surgical procedure that requires taking two main steps. The first step is similar to sleeve gastrectomy. Again, a large portion of the stomach is removed, but valve which leaves food in small intestine remains with a limited portion of the small intestine normally attached to the stomach.

In the second step, the small intestine is divided into two separate paths and a common channel. Thus, the received food is thrown out by skipping a large part of intestine. (5)


  • Weight loss of more than 60-70% over an average follow-up of 5 years
  • The normalization of diets over time
  • Reduction of fat absorption by 70%
  • Appetite reduction and increase in satiety by causing positive changes in intestinal hormones
  • The most effective bariatric surgery to solve the problem of diabetes


  • More serious complications than other surgical procedures
  • Requiring long stay in hospital
  • Long-term problems due to severe vitamin-mineral-protein deficiency
  • Strict on diet, vitamin supplement intake and follow-up visits

Intragastric balloon (Stomach balloon)

The intragastric balloon is a non-surgical gastric reduction process using endoscopic method. It is applied to people who cannot be treated surgically (less than 35 BMI ) to support diet-exercise or to prepare people more than 60 BMI for surgery. The balloon should be removed from the stomach after 6 months. The disadvantage of this procedure is that most patients regain their weight when the balloon is removed from the stomach. (6)

How is bariatric surgery performed?

It is performed in two ways:

  • Open surgery: The surgeon makes a single large incision in the abdomen. Due to its risks, it is no longer a preferred method. It is generally applied to people who have a high level of obesity, have had previous stomach surgery or have other complex medical problems.
  • Laparoscopic surgery: In this method, only a few small incisions are made and the operation is performed with thin surgical instruments inserted through the incision by looking at the images transferred to the monitor with the illuminated special camera system called laparoscope. This method is usually preferred in bariatric surgery operations, because it carries less risk than open surgery, causes less pain and causes faster postoperative recovery.

Preparation before bariatric surgery

  • If the patient smokes, he/she should stop smoking at least 6 weeks before the operation.
  • He/she should comply with restrictions on eating, drinking and medicines.
  • He/she may need to start a physical activity, exercise program.

In some cases, losing weight before surgery and bringing blood sugar levels closer to normal may reduce the risk of problems with the surgery.

What are the risks of bariatric surgery?

As with all major surgeries, bariatric surgery poses potential health risks in both the short and long term. The risks associated with the surgical procedure are:

  • Excessive bleeding
  • Infection
  • Adverse reactions to anesthesia
  • Blood coagulation
  • Lung or respiratory problems
  • Leakage from the rest of the stomach into the abdominal cavity
  • Diarrhea
  • Death (rare)

Long-term risks and complications vary depending on the type of surgery. Typically it can include:

  • Intestinal obstruction
  • Dumping syndrome (rapid gastric emptying) causing diarrhea, nausea or vomiting
  • Gallbladder stones (due to rapid weight loss)
  • Hernia development in the abdominal region
  • Low blood sugar (hypoglycemia)
  • Anemia and osteoporosis (due to inadequate nutrient intake)
  • Perforation of the stomach (gastric bands may cause this)
  • Ulcer
  • Nausea, vomiting and swallowing problems
  • Death (rare)

After bariatric surgery

  • It is necessary to rest and recover after surgery. Although the follow-up method will vary according to the type of surgery, you should not forget to take the supplements recommended by your doctor.
  • Walking around the house can help you recover more quickly. Start slowly and follow your doctor’s advice on the type of physical activity you can safely do.
  • After surgery, most patients switch from a liquid diet to a soft diet such as cottage cheese, yogurt or soup, and a few weeks later to solid foods. Your doctor or dietician will tell you which foods and beverages you can consume and which ones you should avoid.

Recommendations for bariatric surgery

  • Bariatric surgery is a very dangerous surgical procedure that can rarely cause complications like death. Therefore, do not jump on the idea of surgery before trying a diet, exercise or some reliable weight loss medications.
  • Bariatric surgery can only have permanent results if supported by diet and exercise. It is useful to change your lifestyle after surgery.
  • It is very important to be psychologically prepared for such an operation. Assess yourself realistically by seeing an expert.
  • When you decide to go for the surgery, you should investigate the surgeon and the hospital. Learn the success ratio of bariatric surgery.
  • Ask your doctor about the risks of bariatric surgery.
  • Contact patients who have undergone bariatric surgery and learn about their experiences.

Inline Feedbacks
View all comments