Bariatric (Weight Loss) Surgery

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Bariatric surgery, also known as weight loss surgery, is one of the specialties of general surgery. This procedure is typically performed when traditional methods like diet and exercise have been unsuccessful or when patients’ weight is causing severe health issues. To assist in weight loss, bariatric surgery entails altering your digestive system. It can limit the amount of food you can eat or decrease body nutrient absorption, and some surgeries combine both approaches.

Bariatric Procedure Types | Gastric Sleeve Surgery

What is bariatric surgery surgery?

Bariatric surgery is a collection of surgical procedures aimed at assisting individuals with obesity in losing weight. Healthcare professionals may recommend bariatric surgery if other weight loss methods have proven ineffective and if obesity poses a greater health risk than the surgery itself.

Bariatric surgery procedures modify the digestive system, typically by altering the stomach and sometimes the small intestine, to regulate calorie consumption and absorption. Additionally, they can diminish hunger signals that travel from the digestive system to the brain.

These procedures are effective in treating and preventing various metabolic diseases associated with obesity, such as diabetes and fatty liver disease. However, weight loss surgery is not a simple "quick fix" and requires adequate preparation beforehand and long-term lifestyle changes afterward to achieve success.

While bariatric surgery can provide numerous advantages, it is a major operation that carries significant risks and potential side effects. Additionally, to ensure the long-term success of the surgery, you must commit to making permanent, healthy changes to your diet and exercise habits. (1)

Types of bariatric surgery

Bariatric surgery, also known as weight loss surgery, is a type of surgical procedure that helps people who are severely overweight or obese to lose weight by reducing the size of their stomach, and/or altering their digestive system. There are currently 5 different types of bariatric surgery, including:

  • Gastric Sleeve
  • Gastric Bypass
  • ​​Adjustable Gastric Band
  • Biliopancreatic Diversion with Duodenal Switch (BPD-DS)
  • Stomach Intestinal Pylorus Sparing Surgery (SIPS)

Bariatric procedures can be classified into three main categories: blocking, which decreases the absorption of nutrients; restricting, which reduces the size of the stomach and limits the amount of food that can pass through; and mixed, which alter gut hormone levels related to hunger and satiety. 

However, this categorization may not be entirely straightforward. For instance, even though Sleeve Gastrectomy was initially thought to operate solely by decreasing stomach size, research has revealed changes in gut hormone signaling. The two most frequently performed procedures are Sleeve Gastrectomy and Roux-en-Y Gastric Bypass, with Sleeve Gastrectomy accounting for more than 50% of all procedures since 2014. (2)

Who is a candidate for bariatric surgery?

Bariatric surgery is a weight loss surgery that can be considered for individuals who are severely obese and have been unsuccessful with traditional methods of weight loss. The following are qualifications that determine if an individual is a good candidate for bariatric surgery:

  • A BMI of 40 or greater is typically considered an indication for bariatric surgery.
  • Individuals with a BMI of 35 or greater, accompanied by obesity-related health issues such as type 2 diabetes, high blood pressure, or sleep apnea may also be considered suitable candidates. 
  • Individuals who have made unsuccessful attempts to lose weight using traditional methods such as diet and exercise may also be considered.

It is important to note that a thorough medical evaluation is necessary to determine if a person meets the bariatric surgery requirements. Factors such as age, overall health, and medical history are taken into account to assess the suitability of the individual for the procedure. It is crucial that individuals understand the potential risks and benefits of bariatric surgery and commit to making necessary lifestyle changes such as adopting healthy eating habits and regular exercise to maintain long-term weight loss success. (3,4)

Risks and Side Effects

Compared to other methods of treating obesity, weight loss surgery in adults carries a greater risk of complications. According to a 2012 study by the American Society for Metabolic and Bariatric Surgery, the likelihood of significant complications from weight loss surgery is 4%. Among the three primary weight loss procedures, sleeve gastrectomy had the lowest rate of complications and reoperations.

Within a 10-year study period, 8.94% of patients who underwent sleeve gastrectomy required reoperation within 5 years, while 12.27% of patients who underwent Roux-en-Y gastric bypass required reoperation. 

Both of these percentages were lower than those associated with adjustable gastric banding. The likelihood of complications appears to be reduced when the procedure is performed by an experienced bariatric surgeons, and guidelines suggest that the surgery be performed in specialized or experienced units.

Leak rates have declined globally, with a mean rate of 1-5%. It has been observed that low-volume centers have a higher rate of leaks, while high-volume centers have a lower rate of leaks. (5)

Similar to any major surgery, bariatric surgery has potential health risks that can occur both in the short term and long term.

The surgical procedure can cause complications such as 

  • excessive bleeding, 
  • infection, 
  • adverse reactions to anesthesia, 
  • blood clots, 
  • lung or breathing issues, 
  • leaks in the gastrointestinal system.

Over the long term, the risks and complications of weight-loss surgery can vary depending on the type of surgery. These may include 

  • bowel obstruction, 
  • dumping syndrome resulting in diarrhea, flushing, lightheadedness, nausea or vomiting, 
  • acid reflux, 
  • hernias, 
  • low blood sugar (hypoglycemia), 
  • malnutrition, 
  • ulcers,
  • gallstones,
  • the need for a second surgery or procedure. (6)

Post-Procedure and Follow-up

Following weight-loss surgery, it's typical to refrain from eating for one to two days, allowing your digestive system and stomach to recuperate. Subsequently, a specific diet must be adhered to for several weeks, commencing with liquids only, progressing to pureed and easily digestible foods, and eventually normal foods. Your eating and drinking habits may be restricted or limited.

During the first few months after weight-loss surgery, you'll have frequent medical checkups to monitor your health. These checkups may involve laboratory testing, blood work, and various examinations. (7)


After the bariatric surgery, patients will need to spend a few days in the hospital followed by a few weeks of recovery at home before they can return to work. During the recovery period, they may need to avoid intense physical activity for up to six weeks, and it may take up to 12 weeks before they can resume a normal diet. (8)


The amount of weight that a patient can lose after gastric bypass or other bariatric surgeries varies depending on the type of surgery and lifestyle changes made. It's possible to lose up to half or more of the excess weight within two years of the surgery, providing long-term weight loss benefits. (9)

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