Gastric sleeve and gastric bypass are weight loss surgeries that help you eat less by reducing the size of your stomach. There are several key differences in benefits, risks, and recovery.

Bariatric surgery is a procedure that helps you lose weight. It’s an option when you need to lose a lot of weight, especially if improving your diet, becoming more active, and taking diet pills haven’t worked.

Two of the most common types of bariatric surgery are gastric sleeve surgery and gastric bypass surgery.

There are similarities between the two procedures as well as key differences.

Read on for a closer look at what these surgeries entail and when to consider one over the other.

illustration comparing how the stomach looks after gastric sleeve surgery with how the stomach looks after gastric bypass surgeryShare on Pinterest
Illustration by Diego Sabogal

Both gastric sleeve and gastric bypass surgery reduce your stomach from its regular size to a small pouch. This causes weight loss in two ways:

  • The pouch fills up quickly, restricting the amount of food you can eat before you feel full.
  • Your body produces less ghrelin, commonly known as the “hunger hormone.”

The procedures differ in the way surgeons create the new stomach pouch.

Gastric sleeve surgery

With gastric sleeve surgery, the surgeon permanently removes about 80% of your stomach.

What remains is sewn into a small banana-shaped stomach pouch. The surgeon makes no other changes.

Gastric bypass surgery

During gastric bypass surgery, the surgeon creates a small stomach pouch by removing most of your stomach and the first part of your small intestine.

Then, they reconnect the newly created stomach pouch to the remaining small intestine.

The part of your stomach that’s removed is attached further down the small intestine, so it still provides the acid and digestive enzymes produced by those organs.

The portion of your small intestine that’s removed along with your stomach typically absorbs some nutrients and calories. Since food no longer passes through this section, those calories aren’t absorbed, contributing to weight loss.

This procedure is also called Roux-en-Y gastric bypass surgery.

Gastric band surgery

Gastric band surgery is a third type of bariatric surgery.

With this procedure, a surgeon creates a small stomach pouch by placing an inflatable band around part of your stomach.

The size of the opening between the pouch and the rest of your stomach affects how much weight you lose. You can adjust the size by inflating or deflating the band through a port placed under the skin of your abdomen.

A surgeon can easily reverse this surgery by removing the band.

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Gastric bypass surgery is more complicated than gastric sleeve surgery. Gastric sleeve surgery only involves one step, while gastric bypass surgery is a two-step procedure.

Laparoscopic surgery

Surgeons usually perform both procedures laparoscopically. This involves inserting tools, including a laparoscope (lighted scope with a camera), through several small incisions in your abdomen to perform the surgery.

If everything goes well, you won’t have a lot of postoperative pain, and you’ll be able to keep liquids down.

You’ll typically go home 1 to 4 days after gastric sleeve surgery or gastric bypass surgery, according to NHS Wales.

An older 2014 study looked at U.S. data on laparoscopic gastric bypass surgeries conducted in 2011. The researchers found that the median hospital stay was 2 days, and only 26% of people stayed in the hospital for at least 3 days.

If you have a lot of pain after either surgery, aren’t able to keep liquids down, or have other issues, you may need to spend a few extra days in the hospital.

Although gastric sleeve and gastric bypass surgery require similar hospital stays, gastric bypass surgery has a longer recovery process overall. NHS Wales states that it may take 4 to 6 weeks to fully recover from gastric bypass surgery and 2 to 3 weeks to fully recover from gastric sleeve surgery.

Open surgery

Occasionally, laparoscopic surgery isn’t possible, so the surgeon performs open surgery.

It requires a much larger abdominal incision. This type of incision takes longer to heal than small laparoscopic incisions.

Some of the reasons you might need open surgery include:

  • having a high level of obesity
  • having significant medical issues in addition to obesity
  • a prior history of stomach surgery

If you have open surgery, you’ll be in the hospital until your incision has healed enough for you to go home. According to the Washington University Weight Loss Surgery Program, this often means 4 to 5 days in the hospital.

Once you’ve left the hospital, you’ll need time to fully recover.

You may have to wait up to 12 weeks before you can resume most of your normal activities, according to Garnet Health.

Bariatric surgery is a relatively safe procedure.

According to the American Society for Metabolic and Bariatric Surgery (ASMBS), the risk of a major complication is about 4%. This is much lower than the risk of developing serious obesity-related health issues.

Some factors that can complicate any surgery, including bariatric surgery, include:

Possible complications after bariatric surgery include:

Complications from gastric sleeve surgery

Complications specific to gastric sleeve surgery include:

Complications from gastric bypass surgery

Complications specific to gastric bypass include:

The dietary changes you’ll have to make after gastric sleeve surgery and after gastric bypass surgery are generally the same.

According to the National Health Service (NHS):

  • You’ll only take in liquids for the first few days after your surgery.
  • Shortly after, you’ll be able to eat puréed food and then soft food. You’ll continue this diet for the 4 to 6 weeks following your surgery.
  • Six weeks after surgery, you’ll be able to eat regular food.

Important dietary guidelines that you’ll need to follow after your gastric sleeve or gastric bypass surgery include:

The main postoperative difference is the size of your stomach pouch, which affects how much you can eat.

With gastric bypass, your pouch holds about 1 ounce (oz.) of food, which is slightly smaller than a golf ball. Gastric sleeve surgery creates a pouch that holds 2 to 5 oz. of food.

Your pouch will stretch over time. It’s important not to overeat after bariatric surgery because your pouch can stretch enough for you to regain the weight you lost.

According to the AMBS, around 90% of people who undergo bariatric surgery lose 50% of their excess body weight. They can maintain much of their weight loss in the long term.

Success rates vary depending on the type of surgery.

One 2014 study focused on people with morbid obesity who had bariatric surgery between 2008 and 2010. The researchers found that participants who had laparoscopic gastric sleeve surgery lost, on average, 49.2% of their excess body weight after 6 months. During that same period, those who had laparoscopic gastric bypass surgery lost an average of 52.9% of their excess body weight.

A 2018 follow-up study examined how much weight these same participants had lost 5 years after their surgery. During this time, participants who had laparoscopic gastric sleeve surgery lost an average of 49% of their excess body weight. Participants who had laparoscopic gastric bypass surgery lost an average of 57% of their excess body weight.

One of the biggest advantages of gastric sleeve and gastric bypass surgery is that they significantly reduce your risk of obesity-related conditions, such as:

In many cases, bariatric surgery can also help improve physical function, mood, and quality of life. According to a 2019 study, you might even be able to take fewer prescription medications over time. This can reduce your healthcare costs, helping you save money.

Bariatric surgery could also reduce your risk of premature death.

On the other hand, bariatric surgery has several risks which are important to consider.

In addition to surgery-related complications and side effects, a 2020 study showed that many people require follow-up interventions, surgeries, and hospitalizations within 5 years of surgery.

Bariatric surgery can also affect nutrient absorption. Over time, this may lead to health problems such as anemia and osteoporosis.

Gastric sleeve surgeryGastric bypass surgery
helps you lose more weight
results in quicker weight loss
has a lower risk of complications
has a faster recovery time
is reversible
is less likely to cause dumping syndrome (rapid gastric emptying)
is less likely to cause gastroesophageal reflux disorder (GERD)
causes fewer issues with nutrient absorption
reduces the absorption of a greater amount of calories
is appropriate for certain high risk medical conditions
is less likely to require follow-up procedures

Bariatric surgery can cost between $16,000 and $25,000, according to a 2016 article from the New York Times. A 2017 literature review found that costs could range from $7,423 to $33,541, with an average cost of $14,389.

The cost depends on several factors, including:

  • your geographic location
  • whether you have any complications during surgery
  • the type of surgery

Because gastric bypass is more involved, it’s typically more expensive than gastric sleeve.

The amount covered by medical insurance depends on your insurance provider and state.

Certain types of insurance, such as Medicare and Medicaid, may cover the procedure if you meet specific criteria and have a recommendation from a healthcare professional.

Other insurance providers may require you to use an approved surgeon or healthcare facility and prove that you couldn’t lose weight through other methods. This often means completing a nonsurgical weight loss program.

Consider consulting a healthcare professional or contacting your insurance provider for more details about costs and specific coverage requirements.

The type of bariatric surgery that’s best for you will depend on several factors, including your:

  • current weight
  • weight loss goals
  • medical history
  • preexisting health conditions
  • expectations
  • personal preference

Talk with a doctor about these factors and whether bariatric surgery is appropriate.

They can help you determine your eligibility and which procedure might be the best choice.