Weight Loss Surgery: Overview

It can help improve health conditions caused by obesity.

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Weight loss surgery (also referred to as bariatric surgery) can help treat obesity, which is a chronic condition that can lead to an array of other health issues, such as type 2 diabetes, high blood pressure, sleep apnea, heart disease, and more.

Obesity can be hard to treat through diet and exercise alone, and weight loss surgery can help shed excess weight with lifestyle adjustments such as a strict, monitored diet and regular exercise routine as permanent next steps to maintain and contribute to further weight loss.

Here’s what you need to know about weight loss surgery, including the various procedures, who is the best candidate for weight loss surgery, risks, and more.

woman discussing weight loss surgery with doctor
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Purpose of Weight Loss Surgery

Weight loss surgery is a procedure that makes the stomach smaller so that you eat less and feel fuller more quickly and/or makes changes to the small intestine to alter how your body absorbs calories and nutrients you take in through food.

Weight loss surgery is most commonly performed on adults who have a body mass index (BMI) between 35 to 40 or may be performed on those with a BMI of 30 who also have a serious health problem that’s been caused by their obesity.

For children, diet and exercise is always a first step when it comes to dealing with health problems stemming from weight gain, but in some cases, teens who have gone through puberty and have a BMI of 35 to 40 with health problems like sleep apnea, type 2 diabetes, high blood pressure, or high cholesterol may also be considered for surgery.

BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age.
Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.


There are a few contraindications when it comes to weight loss surgery. Aside from age of the patient, BMI, and how successful they were in adhering to their pre-surgery treatment plan a few medical exceptions to surgery include patients dealing with:

All weight loss surgery procedures require general anesthesia, so those who cannot or have issues with general anesthesia may also be prevented from getting surgery.

How to Prepare

Weight loss surgery is typically done laparoscopically and is a scheduled procedure that is only performed after you’ve met a number of criteria with your healthcare team. This preparation can take anywhere from six to 12 months before you get the green light for surgery.

While weight loss surgery is minimally invasive, you can expect to stay in the hospital two to three days to monitor how you’re adjusting to a smaller stomach size and how well you’re able to handle liquids before being discharged.

What to Expect on the Day of Surgery

All weight loss surgery techniques have the same end result: making the stomach smaller to restrict the amount of food that gets consumed and absorbed by the body. However, there are several ways to accomplish this depending on the patient.

The most widely practiced procedures are gastric bypass, sleeve gastrectomy, and adjustable gastric band. It’s important to go over all options with your healthcare team so that you pick the right procedure for you.

Gastric Bypass

Here, a small pouch is created by dividing the stomach, while the small intestine is also divided, bringing the bottom end up connecting with the top of the newly created stomach pouch. This helps restrict the amount of food, calorie absorption, and changes the hormones in the gut to feel more satisfied eating less food.

Gastric bypass has a high success rate, with patients losing more than 50% of their excess body weight but may involve lifelong mineral and vitamin supplementation to ensure the body is getting the nutrients it still needs.

Sleeve Gastrectomy

This procedure removes 80% of the stomach, leaving behind a sleeve-shaped smaller stomach that holds less food as well as changes the same gut hormones the gastric bypass procedure does.

While there is the same concern of vitamin deficiencies as with gastric bypass, doing a sleeve gastrectomy may cause more rapid weight loss than some of the other methods (though it’s important to note this procedure is not reversible, while gastric bypass and the gastric band can be reversed if needed).

Gastric Band

During this surgery an adjustable band is placed around the stomach, creating that smaller top pouch that is now responsible for food intake. The size of the band (and therefore, the stomach) is adjusted through a port in the skin. Depending on how much saline solution is injected that band can get bigger or smaller, which will open or close the pouch of the stomach with it.

This type of procedure has the lowest risk of vitamin deficiencies as well as no cutting of the stomach or changing the tract of the small intestines, though the success rate of losing at least 50% of excess body weight is lower than patients who received gastric bypass or a sleeve gastrectomy.

Potential Risks

While weight loss surgery is typically an extremely safe and effective way to help treat obesity as well as the health conditions that may be caused by excess weight, it’s still surgery and there can be certain risks associated with it. Common potential risks include:

A Word From Verywell

Weight loss surgery may seem like a drastic step to take in order to get your weight and health in order, but most patients who decide to go through the procedure find in addition to adopting healthy lifestyle habits they are able to successfully lose and maintain a weight loss that over time improves their overall health.

On top of reversing certain conditions, weight loss surgery can increase longevity, boost mental health, and lead to a healthier relationship with food.

If you’re concerned with your weight or have health issues because of excess weight gain bring it up to your healthcare provider. Together, you can start to discuss your options as well as why or why not weight loss surgery may be a good option for you.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. University of California San Francisco. Bariatric surgery for severe obesity.

  2. National Institute of Diabetes and Digestive and Kidney Diseases. Definition & Facts for Bariatric Surgery.

  3. National Institute of Diabetes and Digestive and Kidney Diseases. Potential candidates for bariatric surgery.

  4. Stahl Jonathan, Malhotra Sandeep. Obesity Surgery Indications And Contraindications. Treasure Island, FL: StatPearls Publishing.

  5. Northern Westchester Hospital Northwell Health. What to expect the day of your surgery.

  6. American Society for Metabolic and Bariatric Surgery. Bariatric Surgery Procedures.

  7. Penn Medicine. Is bariatric surgery safe?

By Colleen Travers
Colleen Travers writes about health, fitness, travel, parenting, and women’s lifestyle for various publications and brands.