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Weight-Loss (Bariatric) Surgery

Surgery Overview

Bariatric surgery is surgery to help people lose weight and improve health problems related to weight. It may also be called metabolic surgery. This type of surgery is used for people who have obesity. Weight-loss surgery may be an option for people who have not been able to lose weight or improve weight-related health problems with diet, exercise, and medicines.

There are different types of bariatric surgery. They make the stomach smaller. Some types of surgery also change the connection between your stomach and intestines.

After surgery, you'll need to make new, lifelong changes in how you eat and drink. You'll have the support of your health care team to make these changes. These changes will help you reach your goals and stay at a weight that is healthy for you.

What are the types of weight-loss surgery?

All types of weight loss surgery make changes to your digestive system. Some common types are:

  • Gastric bypass.

    The doctor uses a small part of your stomach to create a smaller stomach. This is connected to the middle part of the small intestine. Food skips (bypasses) the rest of the stomach and part of the small intestine. This surgery is called a Roux-en-Y (say "roo-en-why") gastric bypass.

  • Gastric sleeve (sleeve gastrectomy).

    The doctor removes more than half of your stomach, leaving a thin vertical sleeve, or tube.

What To Expect

You may stay in the hospital for one or more days after the surgery. How long you stay depends on the type of surgery you had.

Most people need 2 to 4 weeks before they are ready to get back to their usual routine.

Your doctor will give you specific instructions about what to eat after the surgery. You'll start with only small amounts of liquids and soft foods. Over time, you'll be able to eat more solid foods. Your doctor may advise you to work with a dietitian. The dietitian can help you get plenty of water each day and eat a variety of healthy foods. Even with a healthy diet, you may need to take vitamin and mineral supplements for the rest of your life.

After surgery, you will not be able to eat very much at one time. You will get full quickly. Try not to eat too much at one time or eat foods that are high in fat or sugar. If you do, you may vomit, get stomach pain, or have diarrhea.

Weight loss

You probably will lose weight very quickly in the first few months after surgery. As time goes on, your weight loss will slow down. You will have regular doctor visits to check how you are doing.


It is common to have many emotions after this surgery. You may feel happy or excited as you begin to lose weight. But having to make a lot of changes in your diet, activity, and lifestyle can also be frustrating and hard. Talk with your doctor if you have concerns or questions or need help finding support.

Think of bariatric surgery as a tool to help you lose weight. It isn't an instant fix. You will still need to eat healthy foods and get regular exercise. You may face some challenges and setbacks, but your weight-loss team can help you learn ways to manage them so you can reach and maintain a weight that's healthy for you.

Why It Is Done

This type of surgery may be an option if you have obesity or health problems related to your weight. You and your doctor may consider surgery if you have not been able to lose weight or improve health problems with healthy eating, exercise, or weight-loss medicines.

How Well It Works

Bariatric surgery is a safe treatment that can help people lose a significant amount of weight and keep it off long-term. It can help improve or even reverse health problems caused by obesity, such as diabetes and high cholesterol. It can also decrease the chance of early death and improve quality of life.

Gastric bypass may lead to greater weight loss and better chances of reducing health problems like type 2 diabetes than adjustable gastric banding. People who get gastric bypass may be less likely to need weight-related surgeries in the future.footnote 1, footnote 2

Sometimes people gain some weight back within a few years after surgery. To get the best results, follow your treatment plan and work with your doctor.


Any surgery has risks. Risks of weight-loss surgery include:

  • An infection in the incision.
  • A blood clot in the leg (deep vein thrombosis, or DVT) or lung (pulmonary embolism).
  • Narrowing of the connection between the stomach and the small intestine. This can cause nausea and vomiting after you eat.
  • Leaking from the stomach into the belly area. The leak can lead to an infection called peritonitis.
  • Gastroesophageal reflux disease (GERD). This can lead to a condition called Barrett's esophagus.
  • The need for more surgeries to fix problems that resulted from the original surgery.

Over time, weight-loss surgery may lead to new problems, like:

Depending on the surgery you have, there may be other risks. Talk to your doctor to understand all of your risks.



  1. Tondt J, et al. (2023). Obesity Algorithm eBook, presented by the Obesity Medicine Association. https://obesitymedicine.org/obesity-algorithm. Accessed October 30, 2023.
  2. Arterburn D, et al. (2018). Comparative effectiveness and safety of bariatric procedures for weight loss: A PCORnet cohort study. Annals of Internal Medicine, 169(11): 741–750. DOI: 10.7326/M17–2786. Accessed November 27, 2023.


Current as of: May 13, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.