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Types of Weight Loss Surgery: Comparison of Bariatric Procedures

Types of Weight Loss Surgery

There are different types of weight loss surgery (bariatric surgery), some of which are commonly performed nowadays.

These are effective weight-loss interventions for patients with morbid obesity or those who have previously struggled to lose weight and have additional health problems associated with obesity.

Previously weight loss surgery was considered the last resort because of the associated complications. 

However, people with multiple comorbid conditions now prefer to undergo a weight loss surgery than wait and develop more complications.

Different Types of Weight Loss Surgery Vs Weight Loss Pills:

Weight Loss Pills reduce body weight, however, the effects are not long-lasting especially when the drugs are discontinued.

Bariatric surgery, especially gastric bypass and gastric sleeve surgery are associated with significant weight loss.

The weight loss is usually sustained even 10 years after gastric bypass and gastric sleeve procedure.

In addition, these types of weight loss surgery are associated with improved glycemic control and long-term weight loss, in addition to improvement in other cardiometabolic parameters.

After bariatric surgery, not only food reservoirs are reduced but certain hormonal changes take place too.

These gut hormones are responsible for the feeling of being full and improvement in metabolic and cardiac health.

One of the greatest benefits of bariatric surgery is curing type 2 diabetes which has been observed in more than half of obese patients.

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Who Should Undergo Weight Loss Surgery?

Currently, there are guidelines that many experts agree on for deciding which patients should have weight loss surgery.

These guidelines were made by organizations like NIH and AHA/ACC/TOC.

The guidelines say:

  • People with a BMI higher than 35kg/m² along with other health problems (weight-related comorbidities) can consider surgery.
  • People with a BMI higher than 40kg/m² without other health problems can also consider surgery.

But there are other things to think about before saying yes to surgery:

  • Trying diets and other ways to lose weight without success.
  • Being mentally and physically stable.
  • Being ready and able to understand how big the surgery is.
  • Having health issues that don’t make it too risky to have surgery.
  • Knowing about the surgery and what happens after.
  • Also, for people with type 2 diabetes who can’t control their blood sugar or lose enough weight with other treatments, and who have a BMI higher than 40kg/m², weight loss surgery might be a good idea.

Who shouldn’t have weight loss surgery?

Right now, the only reason not to have surgery is if someone can’t get out of bed.

After surgery, it’s important to move around to stay healthy and lose weight.

Prader-Willi syndrome makes people eat a lot without control. Surgery doesn’t work well for them.

Age is a tricky topic. Generally, for bypass surgery, people might not do it after 65 years old. And for sleeve gastrectomy, it might be after 70 years old.

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Types of Weight Loss Surgery

There are two main types of weight loss surgeries that work in different ways to help people lose weight:

  • Restrictive Type:

These surgeries make the space for food in the stomach smaller. Examples are laparoscopic adjustable gastric banding and sleeve gastrectomy.

  • Malabsorptive Type:

These surgeries make it harder for the body to absorb nutrients from food and make food pass through quickly. This kind of surgery is like a bypass procedure.

For the malabsorptive surgery, there’s a higher chance of getting gallstones, so doctors often suggest removing the gallbladder before the surgery as a precaution.

Evaluation Before Choosing the Type of Weight Loss Surgery

Before getting weight loss surgery, all patients have a checkup to make sure they can be put to sleep safely for the surgery. This is anesthesia fitness.

Also, doctors make sure that the patients are healthy enough for the specific surgery they’re going to have.

  • Endoscopy is recommended for patients who have GERD
  • Cholecystectomy is recommended in patients who already have gallstones. In the case of a normal gallbladder for 6 months, 300mg of twice-daily ursodeoxycholic acid is recommended for patients undergoing bypass surgery.

Choosing the type of weight loss surgery 

Bariatric surgery includes different types of surgical procedures that are selected based on the amount of weight loss required, BMI, and existing comorbidities.


Laparoscopic Adjustable Gastric Banding (LAGB)

This surgery can be done using different kinds of adjustable gastric bands.

One big benefit is that it helps patients manage their weight loss on their own.

During this surgery, a band is put around the stomach and made tight.

It has a way to add salt water. When the band is filled, it controls how much food the stomach can hold, making people feel full more quickly.


  • Infection
  • Ulceration and erosion of the band.
  • Slippage and leading to obstruction and strangulation of the stomach wall.
  • Pseudo achalasia and megaesophagus will reverse on the removal of the band.

ROUX en Y Gastric Bypass (RYGB)

The procedure has worked really well in helping people lose weight and improve their health.

During the surgery, doctors use staplers to create a small pouch in the stomach that can hold about 100 to 150ml of food.

Then, they cut a section of the small intestine, about 1.5 feet long, using a special stapler.

They connect the bottom part of this cut intestine to the pouch in the stomach. They also reconnect the top part of the cut intestine further down.

After the surgery, people have felt much better. Their problems with acid reflux and stomach ulcers have gone down a lot.


Anastomotic leaks are the most drastic complications of this procedure.

Some other complications are:

  • Marginal ulcer
  • Stenosis of anastomosis
  • Internal herniation and obstruction
  • Cholelithiasis
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Biliopancreatic Diversion

This surgery is complicated, but it leads to a lot of weight loss and many problems afterward.

In this case, doctors remove part of the stomach.

They also connect about 200 cm of the lower part of the small intestine to the smaller stomach pouch.

The remaining small intestine is connected about 50 cm from the end to the rest of the lower small intestine.


The major problems that can happen after this surgery include:

  • Sores on the edge of the stomach
  • Trouble absorbing proteins and fats
  • Dumping syndrome (food moving too quickly through the stomach and intestines)
  • Not getting enough vitamins that dissolve in fat, and lacking certain minerals like Vitamin K and zinc
  • Having more than 2 to 4 bathroom trips per day
  • Passing gas a lot and having bad-smelling stools.

In some cases, protein absorption issues are so bad that doctors have to undo the surgery. That’s why this procedure isn’t used very often.


Doctors like to use this method for people with severe obesity because it helps them lose more weight and control their blood sugar better.

After this surgery, patients need to take extra vitamins and minerals every day.

For example, they might need to take at least 2 grams of calcium every day by mouth.


Duodenal Switch

The duodenal switch is ranked as the third most popular surgery among metabolic surgeries.

This is because it can be completed in two steps and is currently the most suitable option for people who are very obese.

Here’s how it works:

  • In the first step, doctors do a sleeve gastrectomy.
  • Then, in the second step, they use a special stapler to connect the bottom part of the small intestine (ileal limb) to the stomach exit (pylorus).
  • They also connect the rest of the small intestine about 100 cm away from the end (ileocecal valve).


This surgery has almost the same kinds of problems as a biliopancreatic diversion.


This technique helps people lose more weight effectively.

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Gastric Sleeve Surgery (Sleeve Gastrectomy):

This type of surgery involves putting special tubes of certain sizes into the stomach.

Then, using a stapler, the rest of the stomach is cut away, leaving only a specific amount of space for a small amount of food.

Benefits of Gastric Sleeve Surgery for weight loss:

  • It’s relatively easy for surgeons to do.
  • If needed, it can be turned into a different kind of metabolic surgery.
  • There’s a low chance of dumping syndrome (when food moves too fast through the stomach and intestines).
  • There’s no risk of lacking nutrients or not getting enough protein.

Results of Gastric Sleeve Surgery:

  • People usually lose weight well and control their blood sugar better.
  • It causes fewer problems compared to other methods.


  • Infections
  • Deep vein thrombosis (blood clot in a deep vein)
  • Sometimes the treatment doesn’t work
  • Weight might come back, along with other health issues.
  • Sometimes, people need another type of weight loss surgery.
  • There’s a higher chance of having stubborn acid reflux.
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Possible Uses of Gastric Sleeve (Sleeve Gastrectomy) for Various Health Conditions:


Contraindicated procedure

Benefits of LSG

Iron deficiencyRYGB, BPDDuodenal preservation
Chrons small bowel diseaseRYGB, DS, BPDPreservation of small bowel
Transplant patients on immunosuppressive drugsLAGB if on steroids, is relatively contraindicated to RYGB, BPD, and DSMore stable absorption of the antirejection medication
Cardiac failure patientsmalabsorption of medicationMore stable absorption of critically needed medication
Severe arthritis requiring NSAIDsRYGB and BPD contraindicated because of the risk of ulcerStomach preservation allows the continued use of NSAIDs
Unable to comply with close follow upLAGB, RYGB, DS, BPDLess risk of malabsorption and reduced need for LAGB adjustments
Preexisting vitamin deficienciesRGB, DS, BPDPreservation of the entire small gut reduces the risk of vitamin deficiency
Autoimmune disorderLAGBLSG may be a good choice

RYGB: Roux en Y Gastric bypass;

DS: Duodenal switch;

BPD: Biliopancreatic diversion;

LAGB: Laparoscopic adjustable gastric banding;

LSG: Laparoscopic sleeve gastrectomy

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Comparison of Various Types of Weight Loss Surgery:


Sleeve gastrectomy

Roux en y gastric bypass

Weight loss49%57%
BMI at 5 years31.6-36.632.5-35.4
Remission of type 2 diabetes12%-61.5%25%-67.9%
Remission of HTN29%-62.5%51-70.3%
LDL mg/dl104.3-116.196.5-101
Quality of lifeImprovedImproved
Remission of GERD25%60.4%
Late complications14.9%-19%17.3-26%
CostLess costlyMore costly
Technical difficultyLessMore

In addition, patients who undergo gastric bypass are usually more satisfied with their weight loss and surgical intervention than those who have gastric sleeve surgery [Ref].

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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