Last updated date: 30-May-2023

    Medically Reviewed By

    Interview with

    Dr. Yong Jin Kim

    Medically reviewed by

    Dr. Lavrinenko Oleg

    Originally Written in English

    Bariatric Surgery Facts - Viewpoints from Expert Doctors

      Today we are talking about a growing global health problem. From 1975 to 2016, the prevalence of this health issue increased more than four-fold, from 4% to 18% globally, especially in children and adolescents aged from 5 to 19 years old.

      Obesity is a serious public health issue that has reached epidemic proportions in Western culture. Obesity is a substantial risk factor for numerous illnesses and is connected with significant morbidity and death, according to mounting evidence.

      Obesity is a multifaceted chronic illness impacted by the interplay of numerous variables, including genetic, endocrine, metabolic, environmental (social and cultural), behavioral, and psychological components. The primary process includes an increase in energy intake that surpasses an increase in energy production.

      The body mass index(BMI)  is the most frequently used indicator of obesity. This figure is obtained at by dividing a patient's mass (kg) by his or her height squared (m2). A normal BMI is defined as being between 18.5-24.9 kg/m2. Overweight is defined as a BMI of 25-29.9 kg/m2. Obesity is defined as having a BMI of 30 kg/m2 or above; this categorization is further split into class I, II, or III obesity.

      After dieting, exercise, psychotherapy, and medication therapies have failed, surgery for obesity should be considered as a last option.


      Epidemiology of Obesity

      The world's overweight population is projected to be 1.7 billion people. The issue has reached pandemic proportions in the United States. In the United States where, up to two-thirds of the population is overweight, and half of those in this category are obese.

      This means it is a serious health issue! Does that ring a bell in your head? 


      Bariatric Surgery


      Bariatric surgery definition:

      Bariatric surgeries, also known as weight-loss surgeries, are a variety of procedures performed on obese people who can’t lose weight in traditional ways or who have serious health conditions due to obesity. 

      Currently, bariatric surgery is the only method that achieves considerable, long-term weight loss for severely obese individuals, resulting in improvements in obesity-related comorbidities.

      Bariatric surgeries can achieve long-term weight loss. They involve making changes to the digestive system to help lose weight. There are many types of them. Some are restricting which means they limit how much you can eat by shrinking the size of your stomach and slowing down digestion. While others are said to be malabsorption, reducing the body’s ability to absorb nutrients. 

      Bariatric surgeries offer many health benefits; however, you should be aware that they are major surgeries that can pose some serious risks and side effects. You should also be aware of the permanent healthy diet and lifestyle changes that accompany that kind of surgery. 


      Why is Bariatric surgery performed?

      Obese individuals at high risk of morbidity and mortality who have not lost enough weight with lifestyle and medication treatment and are suffering from obesity-related comorbidities should be evaluated for bariatric surgery. Bariatric surgery can result in significant weight loss, resolution of comorbid illnesses, and an overall improvement in quality of life.

      The patient's weight-loss history; personal accountability, responsibility, and comprehension; and the acceptable degree of risk must all be considered. A multidisciplinary team must monitor you for the rest of your life.

      These procedures aren’t there haphazardly, on the contrary, they are very helpful for obese people who have life-threatening weight-related health problems including:

      • High blood pressure. 
      • Heart-related diseases. 
      • Strokes. 
      • Sleep apnea. 
      • Type 2 diabetes. 
      • Sexual problems. 
      • Non-alcoholic fatty liver disease. 

      They are only done if you have tried conventional ways such as diet and exercise and they didn’t work out. 


      Are there specific eligibility criteria for bariatric surgery?

      There are some conditions to be able to take bariatric surgery into your consideration:

      • Your body mass index is 40 or higher, which is an extreme obesity level. 
      • Your body mass index is 35 to 39.9 but you have a weight-related serious health problem such as those health problems we mentioned earlier. 
      • Some severe cases might qualify for bariatric surgery even when their body mass index is 30 or 34, only because their health condition is significantly serious. Therefore, they are not for everyone. 

      An open method or a laparoscopic technique can be used for bariatric surgery. The laparoscopic method has grown in popularity.


      Types of Bariatric Surgery 


      Common types of bariatric surgeries


      1- Roux-en-Y gastric bypass

      This is one of the most common types of gastric bypass, and it typically works by reducing the amount of food you eat at each meal and reducing the absorbed nutrients. This type is irreversible because it includes cutting across the top of your stomach and sealing it off from the rest of it. This results in a small pouch that is now considered the stomach. The normal stomach can hold about 3 pints of food, but after this surgery, it can hold only an ounce of food. After sealing the stomach, your surgeon will cut your small intestine and sew part of it directly to the small pouch of the stomach. This way the food you eat will pass through the small pouch then to the middle part of the small intestine sewn to it bypassing a large part of the stomach and the first part of the small intestine. 


      2- Sleeve gastrectomy

      In this surgery, about 80% of your stomach size is removed leaving a small tube-like pouch that holds small amounts of food. Besides, this surgery helps to reduce the appetite-regulating hormone called “Ghrelin” because the small resulting pouch will produce lesser amounts, which consequently, lessens your desire to eat. Sleeve gastrectomy has many advantages over other weight-loss procedures. It requires less hospital stay. It also results in significant weight loss without the need to reroute the small intestine. 


      3- Biliopancreatic diversion with duodenal switch

      This is a two-part surgery with its first step typically similar to sleeve gastrectomy. The second step involves rerouting the end portion of the intestine and connecting it to the duodenum near the stomach. This way the ingested food bypasses the majority of the intestine. This type of surgery limits both the ingested food and absorbed nutrients. Therefore, in the long term, it can cause vitamin or nutrients deficiency. 


      4- Adjustable gastric band

      The idea of this surgery is to make a smaller stomach pouch that receives only a small amount of food and satisfies your hunger quickly. This feeling of fullness depends on the size of the opening between the small pouch and the rest of the stomach which is controlled by the band. This band can be filled with sterile saline that is injected through a port located under the skin. Reducing the size of the opening occurs over time by multiple fills into the band. It is considered a restrictive surgery. Advantages of this surgery include no cutting of the stomach or rerouting of the intestine, being reversible or adjustable, reducing the amount of ingested food, and inducing excess weight loss. 


      5- Vagal blockade or vBloc

      Your surgeon will implant a device more like a pacemaker that sends signals to the brain that the stomach is full. The vagus nerve extends from the brain to the stomach, that’s why the device is located under the rib cage and can be controlled by remote control. One of the most notable advantages is that it is the least invasive surgery. On the other hand, if the battery is completely drained, your surgeon will have to reprogram it. It may also have some side effects such as heartburn, nausea, vomiting, chest pain, belching, and difficulty in swallowing. 


      6- Gastric balloon

      It is a type of restrictive surgery where an inflatable balloon is passed through your mouth into your stomach and then filled with saline which gives you a sense of fullness. It is not meant for people who have had previous bariatric surgery, who have liver failure, or bowel disease. 


      These are the most commonly performed bariatric surgeries. As we mentioned before they are considered major surgeries and major surgeries usually have some risks. 


      Bariatric surgery procedure

      • Health care providers will give you a list of instructions to follow according to the type of surgery you are undergoing.
      • However, there are some common rules you need to know about. Naturally, you will be asked to do various lab tests and investigations. You may have restrictions on what you eat and drink, you may also be advised to enroll in a physical activity program and to stop smoking.


      Bariatric surgery side effects

      Bariatric surgeries can pose some risk factors in both the long and short term. 

      • The short-term risks are general risks that can occur with many procedures such as: 
      1. Blood clots. 
      2. Bleeding. 
      3. Infection. 
      4. Adverse reaction to anesthesia. 
      5. Lung or respiratory problems. 
      6. Gastrointestinal tract leaks. 


      • Long term risks vary according to the type of surgery but here are some of the common risks:
      1. Ulcers. 
      2. Gallstones. 
      3. Hernias. 
      4. Vomiting. 
      5. Malnutrition. 
      6. Acid reflux. 
      7. Bowel obstruction. 
      8. Hypoglycemia, or low blood sugar. 
      9. A second surgery, a revision surgery. 


      Although there is a statistical rise in the number of patients requiring cholecystectomy following obesity surgery, the number is modest enough to avoid proposing a preventive operation at the time of their bariatric surgery.

      The following risk factors have been linked to an increased likelihood of postoperative morbidity:

      • Recent myocardial infarction/angina
      • Stroke
      • Higher BMI
      • Bleeding disorder
      • Hypertension



      When performed by skilled surgeons, the 30-day surgical mortality rate for gastric bypass is around 0.5 percent. In specialist centers, the probability of dying during the first month following a Roux-en-Y gastric bypass due to complications is roughly 0.2-0.5 percent.

      According to studies, the death rate recorded by hospitals with less expertise with the surgery is significantly greater than the mortality rate reported by specialist institutions. Laparoscopic gastric bypass has a greater risk of intra-abdominal problems than open operations, but the hospitalization time is shorter, wound complications are lower, and postoperative patient comfort is higher.

      Gastric bypass surgery and other bariatric procedures can result in long-term weight reduction. The amount of weight you lose is determined on the type of surgery you have and the changes you make in your lifestyle. Within two years, you may be able to shed half, if not more, of your additional weight.

      In addition to weight reduction, gastric bypass surgery may treat and resolve problems commonly associated with obesity, such as:

      • Type 2 diabetes
      • Hypertension
      • Heart disease
      • Obstructive sleep apnea
      • Nonalcoholic fatty liver disease (NAFLD)
      • Gastroesophageal reflux disease (GERD)
      • Osteoarthritis (joint pain)


      Which surgery would be best for you? 

      • The answer to this question depends on many factors including your body type, your personal preference, your compliance, and your health. 
      • For example, if you are obese and you had previous surgery, the simpler surgeries are not for you. Therefore, searching for the best surgery for you is a difficult task. 
      • You can’t just find the right answer on pages of social media and among the lines of many articles. The type of surgery you are looking for is part of a treatment plan and surgery is only one step in this plan. That’s why you need to ask professionals to customize a personal plan for your case. 


      Postoperative Care

      Patients must continue to eat a high-protein, low-fat diet after surgery, and they must supplement their diet with multivitamins, iron, and calcium on a twice-daily basis. Ursodiol may be administered to reduce the chance of developing gallstones during the acute weight loss stage. Patients must change their eating habits by avoiding chewy meats and other items that may interfere with regular stomach pouch emptying.

      Nutritional and metabolic blood tests should be done on a regular basis; in the author's practice, these tests are done 6 months after surgery, 12 months after surgery, and then annually after that.



      • Bariatric surgery is not recommended for those who have advanced cancer or end-stage renal, hepatic, or cardiac disease, as these conditions significantly shorten life expectancy and are unlikely to improve with weight loss.
      • Untreated schizophrenia, ongoing drug addiction, and noncompliance with past medical care are all considered contraindications to bariatric surgery.
      • Positive bariatric surgery outcomes might lead to socioeconomic development, which may necessitate patient supervision. For certain patients, postoperative treatment may also entail planning for reconstructive surgery after weight stability.


      Bariatric surgery recovery

      Postoperative bariatric surgery patients should be cared after for the rest of their lives, including at least three follow-up appointments with the bariatric surgery team during the first year. Laparoscopic adjustable gastric banding necessitates more frequent band adjustments. Counseling, support groups, and the patient's family physician should all help to reinforce postoperative dietary modifications (including vitamin, mineral, and perhaps liquid protein supplements), exercise, and lifestyle improvements.


      Life after weight loss surgery

      Weight reduction surgery can result in significant weight loss, but it is not a treatment for obesity in and of itself. To avoid regaining weight after surgery, you must commit to making permanent lifestyle changes.

      You'll need to:

      • Change your diet 

      In the weeks following surgery, you'll be on a liquid or soft food diet, but you'll gradually transition to a regular balanced diet that you'll need to follow for the rest of your life.

      • Exercise regularly

      When you've recovered from surgery, you'll be encouraged to begin and stick to an exercise regimen for the rest of your life.

      • Attend regular follow-up appointments to see how you're doing following surgery and to obtain advice or assistance if necessary.
      • Women who have had weight reduction surgery are typically advised to avoid becoming pregnant for the first 12 to 18 months after the procedure.


      Does Bariatric surgery always work?

      According to studies, many patients who undergo weight-loss surgery lose 15 to 30 percent of their initial weight, depending on the type of operation. However, no treatment, including surgery, is guaranteed to result in and sustain weight loss.

      Some patients who have weight-loss surgery may not drop as much weight as they expected. Some people recover some of the weight they lost over time. The amount of weight that people recover varies. Weight regain may be affected by a person's weight before to surgery, the type of procedure, and adherence to changes in activity and diet.

      Weight-loss surgery can help you eat less calories and be more physically active. Choosing nutritious meals and beverages before and after surgery may assist you in losing more weight and keeping it off in the long run. Regular physical exercise following surgery also aids in weight loss. To enhance your health, you must commit to a lifetime of good living choices and listen to the advise of your health care providers.


      How much does weight-loss surgery cost?

      Weight-loss surgery can cost anywhere from $15,000 and $25,000, or possibly more, depending on the type of operation and whether or not there are any problems. 4 Depending on where you reside, costs may be greater or cheaper. The amount your medical insurance will cover varies depending on your state and insurance provider.


      Bariatric surgery diet

      As part of a complete weight control approach, patients should follow a well-balanced, calorie-reduced diet. Which imposes some dietary suggestions following bariatric surgery.

      To avoid particular nutritional deficiency disorders, such as anemia, lifelong oral or intramuscular vitamin B12 supplementation, as well as iron, vitamin B, folate, and calcium supplements, is suggested.

      Nutrition recommendations after bariatric surgery:

      • Eat 4 to 5 times a day (3 small meals plus 1 to 2 small snacks)
      • Choose mostly solid food for meals and snacks
      • Limit intake of solid food to approximately 1 cup
      • Make time for meals and snacks to eat slowly (15 to 30 minutes) and chew food well
      • Avoid textures that are difficult to chew (eg, tough meats, stringy vegetables, soft breads)
      • Avoid consuming fluids within 30 min of eating any solid foods
      • Consume beverages between meals and snacks
      • Avoid carbonated beverages
      • Avoid higher-sugar foods


      What should you expect after surgery?

      • Every person is unique, every person has specifics of their surgery and they depend on the type of surgery you had, your medical situation, and the hospital and doctor practices. 
      • After surgery, you will need to rest and walk around the house, which will help you recover quickly. You will be advised to start your physical activity as soon as you recover, and you will first start a liquid diet then over several weeks you will then move to a soft diet. Eventually, you will eat solid foods again. 
      • The number of pounds you will lose depends on you and if you follow the rules and also depends on the type of surgery you had. 
      • Your weight loss process could be difficult, but remember, if you stick to your healthy lifestyle plan, you will reach your goal eventually.


      To ensure that you get a comprehensive picture and understand everything regarding Bariatric surgery, we invited Dr. Kim who is a leading doctor at H Plus Yangji Hospital in Seoul, Korea to address any questions you may have from an experienced point of view.



      Dr. Yong Jin Kim Interview


      1. Can you explain a little bit to us about bariatric surgery?

      The background is that the procedure was created to alleviate weight issues. The word itself has the concept of treating obesity. It began around the mid-1950’s. In light of cases where diet, exercise and drugs do not work and the need for reducing weight is present, bariatric surgery is a surgical option.


      2. For bariatric surgery, only obese people can get it, right? What is exactly, how much is severe obesity?

      When we assess obesity, it is technically difficult as we need to delve into the body’s fat levels in every area. So, utilizing height and weight we calculate the body mass index or BMI. We designate obesity by BMI levels. While there are slight differences between regions such as the West versus Asia, is Asia if the BMI index is 30 or above, at a height of 160 cm and a weight of 80 kg or more, we attach the designation of severely obese.


      3. Can bariatric surgery be done by laparoscopy?

      Surely. Today we no longer open up the abdomen from the belly to chest in order to do surgery. We are doing surgery through laparoscopy or robotics 100% these days.


      4.  How many times on average does the surgery take?

      Depends largely on the methods used. Also, depends on the patient’s obesity as well, as the gender. For the common surgery called the sleeve gastrectomy usually only takes an hour or so. It is not a particularly long surgery. 


      5. How much weight is expected to be lost after the surgery?

      Relative to one’s original body weight, usually about 30%. For example, a 100 kg patient would lose about 30 kg. Sometimes as high as 40%. So, about 30% to 40% relative to the original body weight. The process takes a year to year and half. 


      6. Is there an age limit for people who can get bariatric surgery?

      Depends on each country’s insurance policies. In Korea, there is no age limit. Anyone 75 or older or close to one’s life expectancy is not right, in my opinion. Those above 70 are not likely to do this procedure. 


      7. Is there a weight limit for surgery?

      Yes, there is weight limit according to insurance policies. In Korea, it is for those with BMI of 35 or above. For a BMI between 30 and 35, it only for those who have simultaneous conditions as per government guidelines.


      8. What are types of bariatric surgery?

      Broadly speaking, there is a way to simply limit intake of food and a way to limit both intake of food as well as food absorption. There are these two types. In the world, basically there is the sleeve gastrectomy and a method for food to bypass the stomach and the majority of the intestine to go straight to the end of the small intestines. You can think of two types, broadly speaking.


      9. What is the bariatric surgery success rate?

      I cannot say it is 100%. Even though we use a camera to see during the bariatric surgery, we cannot say anything is 100% safe. But the risk is quite low, even relative to what many may assume. The safety level is similar to that of a gallbladder surgery. The risk level is around 2 to 3 percent. Even death is possible, but it is about one in a thousand or so. But one must understand these patients are at risk anyways. They are overweight, older, and male. They have internal organ damage. For example, they have chronic diabetes which led to damage to kidneys. Those without any significant comorbidity factors should not worry about it. 


      10. In these successful cases, the result is permanent? 

      Treatment for obesity is for people with chronic problems with weight issues. Thus, as time passes the patient can regain 5 to 10 percent back. While surgery is a good option, it is a not a perfect panacea. As time goes, some may need additional drugs to help keep the weight off. But on the positive side, about 80% of patients can live a nice life never imagined before. The remaining 20% can still live a life much better than before, albeit not as much as imagined.


      11. What are the risks of the surgery for some people?

      A common complication is infection in the area of surgery, especially for those who smoke. And for those people, the infection does not recover well. That is the biggest risk. Also, after sleeve surgery, digestive acids can swim back up and cause acid reflux. Those are real risks.


      12. What are the tests that the person should take?

      Since it is an abdominal surgery, as expected, we must do a gastroscopy, a CT scan or ultrasound to see the stomach area carefully for other issues, and other tests such as X-rays for the chest, blood tests, etc. for the administration of full anesthesia. Also, it is important to teach diet habits. Post-surgery, you cannot drink water at rapid pace. The main meal will be powdered proteins. It is key to practice these diet habits prior to undergoing surgery. So, prior to surgery, tests such as gastroscopy, chest X-rays and blood tests are done.


      13. Are there some cases who cannot have bariatric surgery?

      Yes, certainly there are such cases:

      • Those with uncontrolled depression. 
      • Those with compromised liver and lung functions and cannot withstand a full anesthesia. 
      • Those with mental disorders. And those with eating disorders.



      The background to bariatric surgery was created to alleviate weight-related problems in patients where diet, exercise and medication no longer work. We assess obesity using height and weight to calculate body mass index or BMI.

      There are two mechanisms for this type of surgery: one way to simply limit the consumption of foods like sleeve gastrectomy and another to limit both the consumption and absorption of foods like roux en Y gastric bypass.

      Weight loss surgery is 100% laparoscopic or robotic these days. How long this surgery lasts depends on the methods used. For a sleeve gastrectomy, for example, it takes about an hour, which is not particularly long.

      Bariatric surgery requires good preparation on the part of a multidisciplinary team, which, too, will ensure regular postoperative follow-up to help the patient adapt to a new, healthier lifestyle to reduce comorbidities and achieve and maintain the goal of the weight.