Bariatric Surgery: Type, Procedure, Pros & Cons

Bariatric surgery is a weight-loss operation that involves changes to your digestive system. By making your stomach smaller, changing the way you absorb calories and nutrients or other methods, it could help you lose weight.

Also, bariatric surgery could also help if you have obesity-related health problems, such as type 2 diabetes, and sleep apnea.

In spite of that, bariatric surgery is not sure to produce and maintain weight loss. And, it could pose some risks and you need to take specific steps (such as diet control) to ensure long-term success of the surgery, as with many other procedures.


According to the American Society for Metabolic and Bariatric Surgery (ASMBS), you may qualify for bariatric surgery if:

  • your BMI (body mass index) is at least 40, and you are more than 100 pounds overweight;
  • your BMI is 35 to 39.9 and you have at least one or more obesity-related co-morbidities such as type 2 diabetes, hypertension, sleep apnea and other respiratory disorders, non-alcoholic fatty liver disease, osteoarthritis, lipid abnormalities, gastrointestinal disorders, or heart disease;
  • you are unable to achieve a healthy weight loss sustained for a period of time with prior weight loss efforts.

In other words, it’s not for everyone who is overweight.

Note: Calculate your BMI here.


Based on the methods used in the operation, bariatric surgery is divided into 4 types:

  • Gastric bypass
  • Laparoscopic sleeve gastrectomy (LSG)
  • Adjustable gastric band (AGB)
  • Biliopancreatic diversion with duodenal switch


Gastric Bypass

Gastric bypass, or Roux-en-Y gastric bypass, is considered the “gold standard” of weight loss surgery.

It involves changes to the stomach and the small intestine.

First, the surgeon divides the top of the stomach from the rest of it and seals it off to create a small stomach pouch, which could hold about 3 pints of food. Then, the surgeon cuts the first portion of the small intestine, brings up the bottom end of the divided small intestine and connects it with the newly created small stomach pouch. Next, the top portion of the divided small intestine is connected to the small intestine further down so that the stomach acids and digestive enzymes from the bypassed stomach and first portion of small intestine will eventually mix with the food.

As a result, you’ll have a smaller stomach for smaller meals.

Laparoscopic Sleeve Gastrectomy (LSG)

The sleeve gastrectomy is also known as the sleeve.

During the operation, the surgeon cuts away approximated 80% of the stomach, leaving the remaining part resemble a banana or “sleeve”.

Adjustable Gastric Band (AGB)

The adjustable gastric band is also called the band.

The name comes from the method that the surgeon places an inflatable band around the upper portion of the stomach, creating a small stomach pouch above the band, and the rest of the stomach below the band.

With the smaller stomach pouch, you’ll feel full after eating just a small amount of food.

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

This is a two-part surgery. First, the surgeon removes a large portion of the stomach, and forms the remaining portion form into a sleeve, similar to sleeve gastrectomy.

The second part involves connecting the end portion of the intestine to the duodenum near the stomach (duodenal switch and biliopancreatic diversion), bypassing the majority of the intestine.

It limits how much you can eat and reduces the absorption of nutrients. While it is extremely effective, it has greater risk, including malnutrition and vitamin deficiencies.


Gastric Bypass

  • Produces significant long-term weight loss (60 to 80 percent excess weight loss)
  • Restricts the amount of food that can be consumed
  • May lead to conditions that increase energy expenditure
  • Produces favorable changes in gut hormones that reduce appetite and enhance satiety
  • Typical maintenance of >50% excess weight loss

Laparoscopic Sleeve Gastrectomy (LSG)

  • Restricts the amount of food the stomach can hold
  • Induces rapid and significant weight loss that comparative studies find similar to that of the gastric bypass. Weight loss of >50% for 3-5+ year data, and weight loss comparable to that of the bypass with maintenance of >50%
  • Requires no foreign objects (AGB), and no bypass or re-routing of the food stream (gastric bypass)
  • Involves a relatively short hospital stay of approximately 2 days
  • Causes favorable changes in gut hormones that suppress hunger, reduce appetite and improve satiety

Adjustable Gastric Band (AGB)

  • Reduces the amount of food the stomach can hold
  • Induces excess weight loss of approximately 40 – 50 percent
  • Involves no cutting of the stomach or rerouting of the intestines
  • Requires a shorter hospital stay, usually less than 24 hours, with some centers discharging the patient the same day as surgery
  • Is reversible and adjustable
  • Has the lowest rate of early postoperative complications and mortality among the approved bariatric procedures
  • Has the lowest risk for vitamin/mineral deficiencies

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

  • Results in greater weight loss than LSG, or AGB, i.e. 60 – 70% percent excess weight loss or greater, at 5 year follow up
  • Allows patients to eventually eat near “normal” meals
  • Reduces the absorption of fat by 70 percent or more
  • Causes favorable changes in gut hormones to reduce appetite and improve satiety
  • Is the most effective against diabetes compared to gastric bypass, LSG, and AGB


Gastric Bypass

  • Is technically a more complex operation than the AGB or LSG and potentially could result in greater complication rates
  • Can lead to long-term vitamin/mineral deficiencies particularly deficits in vitamin B12, iron, calcium, and folate
  • Generally has a longer hospital stay than the AGB
  • Requires adherence to dietary recommendations, life-long vitamin/mineral supplementation, and follow-up compliance

Laparoscopic Sleeve Gastrectomy (LSG)

  • Is a non-reversible procedure
  • Has the potential for long-term vitamin deficiencies
  • Has a higher early complication rate than the AGB

Adjustable Gastric Band (AGB)

  • Slower and less early weight loss than other surgical procedures
  • Greater percentage of patients failing to lose at least 50 percent of excess body weight compared to the other surgeries commonly performed
  • Requires a foreign device to remain in the body
  • Can result in possible band slippage or band erosion into the stomach in a small percentage of patients
  • Can have mechanical problems with the band, tube or port in a small percentage of patients
  • Can result in dilation of the esophagus if the patient overeats
  • Requires strict adherence to the postoperative diet and to postoperative follow-up visits
  • Highest rate of re-operation

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

  • Has higher complication rates and risk for mortality than the AGB, LSG, and gastric bypass
  • Requires a longer hospital stay than the AGB or LSG
  • Has a greater potential to cause protein deficiencies and long-term deficiencies in a number of vitamin and minerals, i.e. iron, calcium, zinc, fat-soluble vitamins such as vitamin D
  • Compliance with follow-up visits and care and strict adherence to dietary and vitamin supplementation guidelines are critical to avoiding serious complications from protein and certain vitamin deficiencies


You may experience low energy for a while and you may need to have several days off. One or two weeks later, you may return to work.

Watch out for infection of the incisions. Contact your surgeon if you don’t feel well.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.