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

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

There are similarities between the two procedures, but there are also key differences.

This article will take a closer look at both surgeries and what they entail, including their pros and cons, and when to consider one over the other.

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

  • the pouch fills up quickly so it restricts the amount of food you can eat before you feel full
  • the amount of ghrelin, commonly known as the “hunger hormone,” is reduced

The two procedures differ in the way the new stomach pouch is created.

Gastric sleeve surgery

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

What remains is sewn into a small banana-shaped stomach pouch. No other changes are made.

Gastric bypass surgery

With this procedure, also called Roux-en-Y gastric bypass, a small stomach pouch is created by removing, or “bypassing,” most of your stomach and the first part of your small intestine.

The newly created stomach pouch is then reconnected to the remaining small intestine.

The bypassed part of the stomach is attached further down the small intestine, so it still provides the acid and digestive enzymes produced there.

The portion of your small intestine that’s removed with your stomach normally absorbs some nutrients and calories.

Since this section is bypassed, the absorption of those calories doesn’t happen, which contributes to your weight loss.

Another option

Gastric band surgery is a third type of bariatric surgery.

With this procedure, a small stomach pouch is created 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 the amount of weight you lose.

This can be adjusted by inflating or deflating the band through a port that’s placed under the skin of your abdomen. Gastric band surgery can be easily reversed by removing the band.

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

Both gastric sleeve surgery and gastric bypass are usually done laparoscopically.

This involves inserting a lighted scope with a camera called a laparoscope and other tools through several small incisions in your abdomen to perform the surgery.

If everything goes well, you don’t have a lot of postoperative pain, and you’re able to keep liquids down. You’ll typically go home 1 or 2 days after gastric sleeve surgery.

If you have a lot of pain after your gastric sleeve surgery, aren’t able to keep liquids down, or have other issues, you may need to spend an extra day or two in the hospital.

Because gastric bypass is more complicated, you’ll likely spend at least 2 days in the hospital, before you’ve recovered enough to go home.

You may need to stay in the hospital for longer if you have complications after the surgery.

Occasionally, laparoscopic surgery isn’t possible, so open surgery is done. This requires a much larger incision in your abdomen. This type of incision takes longer to heal than the small laparoscopic incisions.

If you have open surgery, you’ll be in the hospital until your incision has healed enough for you to go home. This often means 4 or 5 days in the hospital.

Some of the reasons you might need open surgery include:

  • you’ve had surgery on your stomach before
  • you’re extremely overweight
  • you have significant medical problems in addition to obesity

Once you’ve left the hospital, you’ll need time to fully recover. You’ll have to take it easy for 3 or 4 weeks before you can resume your normal activities.

Bariatric surgery is a relatively safe procedure.

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

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:

  • acid reflux
  • leakage of stomach fluid
  • narrowing (stenosis) along the stomach pouch
  • stomach obstruction

Complications from gastric bypass surgery

Complications specific to gastric bypass include:

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

  • For about a week after your surgery, you’ll only take in liquids.
  • For the next 3 weeks, you’ll be able to eat pureed food and then soft food.
  • Two months after surgery, you’ll be able to eat regular food.

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

  • Gastric sleeve surgery creates a pouch that holds about 3 ounces, which is roughly the size of a hockey puck.
  • With gastric bypass, your pouch holds about 1 ounce, or about the size of a golf ball.

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

  • eating small amounts and stopping when you’re full
  • chewing your food thoroughly
  • eating slowly
  • taking the recommended vitamins and supplements
  • staying hydrated by drinking enough water
  • sipping fluids rather than drinking quickly
  • avoiding food that’s difficult to digest, such as tough meat and bread
  • avoiding carbonated beverages

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.

One of the biggest advantages, which applies to both gastric sleeve surgery and gastric bypass is that these procedures significantly reduce your risk for obesity-related conditions, such as:

Pros and cons for gastric sleeve surgery

Gastric sleeve pros

  • You can lose up to 65 percent of your excess body weight.
  • It’s a one-step procedure so there’s a lower risk of complications.
  • The recovery is faster compared with gastric bypass.
  • There are fewer issues with absorbing nutrients and vitamins.
  • Dumping syndrome is less common.

Gastric sleeve cons

  • There’s less weight loss compared with gastric bypass.
  • Weight loss is slower.
  • It can’t be reversed.
  • It can cause acid reflux.

Pros and cons for gastric bypass surgery

Gastric bypass pros

  • You can lose up to 80 percent of your excess body weight.
  • Intestinal bypass results in fewer calories absorbed.
  • You lose weight faster than with gastric sleeve surgery.
  • Although difficult, it can be reversed.

Gastric bypass cons

  • It’s a two-step surgery so there’s a higher risk of complications.
  • The recovery is longer than for gastric sleeve surgery.
  • Intestinal bypass results in the malabsorption of nutrients and vitamins, which can lead to deficiencies.
  • Dumping syndrome is more common.

The type of bariatric surgery that’s right for you depends on several factors, including:

  • your weight
  • your medical history
  • any health conditions you may have
  • your expectations

Talk with your doctor about these factors and whether bariatric surgery is an option for you. Together you can decide if one type of surgery is better suited for you.

Gastric sleeve and gastric bypass are both types of bariatric surgery. There are similarities between the two procedures, but there are also important differences. There are also pros and cons to both surgeries.

If you think you may be a candidate for bariatric surgery, talk to your doctor about the risks and benefits of these procedures and others.

With your doctor’s advice and knowledge, you can decide whether bariatric sleeve or bariatric bypass surgery is right for you.