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Types of Weight Loss Surgery: Comparison of Bariatric Procedures

Types of Weight Loss Surgery

Types of weight loss surgery

Various types of weight loss surgery (bariatric surgery), are effective options for patients with morbid obesity or those who have previously struggled to lose weight and have additional health problems associated with obesity.

Medical vs Surgical intervention in morbid obesity

Medical therapy shows only temporary success in lowering patient weight, while no success is seen on a long-term basis.

Bariatric surgery is the only therapy to show absolute superiority in the effectiveness of weight loss as it has shown both short-term and long-term success.

Multiple long-term patients who underwent bariatric surgery showed better glycemic control and decreased mortality rates.

After bariatric surgery, not only food reservoirs are reduced but it also affects the numerous peptide levels which to decreased appetite and increased satiety levels.

One of the greatest benefits of bariatric surgery is the remission or amelioration of type 2 diabetes because of changes in entering the entero-insular axis due to which insulin resistance is reduced.

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Preoperative selection of patients for bariatric surgery

Currently, the widely accepted guidelines for patients selected for bariatric surgery were formulated by NIH and AHA/ACC/TOC.  These guidelines include:

  • BMI of more than 35kg/m² with associated comorbidity.
  • BMI of more than 40kg/m² with no comorbidity.
  • There are several other factors to consider before considering a patient for surgery.
  • Failure of dietary and behavioral therapy.
  • Physiatric stability.
  • Motivated and able to comprehend the magnitude of surgery.

Criteria for considering surgery

Note that failure of any of these conditions is a contraindication for surgery

  • BMI of more than 35kg/m² with comorbidity or more than 40kg/m² without any comorbidity.
  • Failed dietary therapy.
  • Psychiatrically stable without alcohol dependence or drug abuse.
  • Knowledge about surgery and its sequelae.
  • Motivated individual.
  • Medical condition not precluding probable survival of surgery.

Moreover, metabolic surgery should be recommended for patients with type 2 diabetes who fail to show reasonable glycemic control or considerable weight loss with non-surgical therapies and have a BMI of more than 40kg/m².

Contraindications of weight loss surgeries

Currently, the only surgical contraindication is in patients who cannot ambulate. because post-surgery ambulation is mandatory, to avoid complications and help in weight loss.

Prader Willi is a syndrome of uncontrolled eating. it is also a contraindication for surgery as in this case any surgery won’t be helpful.

Age is a controversial contraindication for surgery. the rough cut-off for bypass surgery is 65 and for sleeve gastrectomy is 70years

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Types of Weight Loss Surgery

Weight loss surgeries are divided into two different types based on their mechanism of inducing weight loss:

Restrictive Type

Reduce food reservoir (laparoscopic adjustable gastric banding, sleeve gastrectomy)

Malabsorptive Type

This type of surgery reduces the absorption area of food and decreases food transit time. Food will have less time to absorb. (bypass procedure)

In malabsorptive surgery risk of formation of gallstones is high so prophylactic cholecystectomy is recommended.

Evaluation before choosing the Type of Weight Loss Surgery

There as two distinct types of evaluation for bariatric surgery. the general type which is done for all patients undergoing general anesthesia

  • 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.

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Laparoscopic adjustable gastric banding (LAGB)

It can be performed with any of the multiple types of adjustable gastric bands.

One of the main advantages is that it helps patients to control individual weight loss.

In this type of surgery, a band is placed around the stomach and secured. It has its conduit for saline. With inflation of the band, it controls food that can be retained in the stomach. Leading to early satiety.


  • 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.
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ROUX-en-Y gastric bypass (RYGB)

Resolution of co-morbid weight loss with this procedure has been excellent and has shown long-term benefits.

In this surgery stomach pouch of 100 to 150ml is created with the help of staplers.

Then almost 1.5 feet of proximal jejunum is cut with the linear stapler and the distal segment is anastomosed with the stomach pouch and the proximal limb is anastomosed back with the distal segment of the jejunum.

Post-surgery there has been a remarkable reduction in symptoms of GERD and gastric ulcers.


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

It is a complex surgery but is associated with more weight loss and a high incidence of complications.

In this case, distal gastrectomy is carried out.

Almost 200 cm of the distal ileum limb is anastomosis with reaming stomach pouch and the rest of the small gut is anastomosed 50cm from the ileocecal valve with distal ileum.


The main complications of this surgery are:

  • Marginal ulcers
  • Protein and fats malabsorption
  • Dumping syndrome.
  • It is also associated with a deficiency of fat-soluble vitamins and numerous minerals, especially Vitamin k and zinc.
  • More than 2 to 4 bowel movements per day
  • Excessive flatulence and foul-smelling stools.

Sometimes protein malabsorption is so severe that reconstruction has to be taken down. That’s why this procedure is not common in use.


This procedure is preferred in patients with morbid obesity because it shows better improvements in weight loss and glycemic control in this group of patients.

Daily supplementation of vitamins and minerals is necessary after this surgery. For instance, at least 2g of daily oral calcium supplementation.

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Duodenal Switch

Duodenal switch is the 3rd most favored surgery in the list of metabolic surgeries because it can be done in just 2 steps and is currently the most suitable type of surgery for severely obese patients

In this procedure, a first-stage sleeve gastrectomy can be done.

Then in the second stage with help of a linear stapler pylorus, the distal 250cm of the ileal limb is anastomosed with pylorus, and the rest of the gut is anastomosed 100cm from the ileocecal valve.

It has almost similar complications as a biliopancreatic diversion


This technique is helpful to achieve greater weight loss

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Sleeve Gastrectomy

In this procedure, bougies of specific sizes are placed in the stomach. With the help of a liner stapler rest of the stomach is resected leaving a specific amount of stomach volume to accommodate a little bit of food.


  • Technically easy
  • It is easily convertible into any other type of metabolic surgery.
  • Minimal risk of dumping syndrome.
  • No risk of malnutrition or protein deficiency


  • Good weight loss control and glycemic control.
  • Less complication compared to other procedures


  • Infections
  • DVT (Deep vein thrombosis)
  • Failure of therapy
  • Recurrence of weight gain and co-morbid medical conditions
  • Requiring conversion to another type of bariatric surgery.
  • High incidence of intractable gastric acid reflux.
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Potential role of sleeve gastrectomy in different medical conditions

Condition Contraindicated procedure Benefits of LSG
Iron deficiency RYGB, BPD Duodenal preservation
Chrons small bowel disease RYGB, DS, BPD Preservation of small bowel
Transplant patients on immunosuppressive drugs LAGB if on steroids, is relatively contraindicated to RYGB, BPD, and DS More stable absorption of the antirejection medication
Cardiac failure patients malabsorption of medication More stable absorption of critically needed medication
Severe arthritis requiring NSAIDs RYGB and BPD contraindicated because of the risk of ulcer Stomach preservation allows the continued use of NSAIDs
Unable to comply with close follow up LAGB, RYGB, DS, BPD Less risk of malabsorption and reduced need for LAGB adjustments
Preexisting vitamin deficiencies RGB, DS, BPD Preservation of the entire small gut reduces the risk of vitamin deficiency
Autoimmune disorder LAGB LSG 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 different types of weight loss surgeries

Factors Sleeve gastrectomy Roux en y gastric bypass
Weight loss 49% 57%
BMI at 5 years 31.6-36.6 32.5-35.4
Remission of typ2 diabetes 12%-61.5% 25%-67.9%
Remission of HTN 29%-62.5% 51-70.3%
LDL mg/dl 104.3-116.1 96.5-101
Quality of life Improved Improved
Remission of GERD 25% 60.4%
Late complications 14.9%-19% 17.3-26%
Cost Less costly More costly
Technical difficulty Less More

What do you think?

Written by Dr. Ahmed

Dr. Ahmed is an experienced Internist with over fifteen years of practice in the medical field. He strongly believes that true medical practice is about helping people, not just prescribing pills.
He has found that the best results come from motivating patients to make small lifestyle changes in addition to prescribing medications when necessary.
With a focus on managing obesity, diabetes, hypertension, asthma, depression, arthritis, migraine, high cholesterol levels, and many more medical conditions in his patients, he shares his knowledge and expertise through writing health-related articles for
He is committed to helping patients achieve optimal health outcomes and improve their quality of life. For direct contact, he can be reached at

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