Roux-en-Y Gastric Bypass Surgery

Gastric Bypass Surgery

Roux-en-Y Gastric Bypass Surgery

Gastric Bypass Surgery or Roux-en-Y Gastric Bypass Surgery is one of the types of weight loss surgery that is associated with significant weight loss and positive health benefits.

It is comparably more effective than gastric sleeve or LSG (laparoscopic sleeve gastrectomy), intragastric balloon placement, and Laparoscopic adjustable gastric banding.

However, because it is more invasive in nature, it is associated with more complications than LSG and gastric banding.

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What is Roux-en-Y Gastric Bypass Surgery?

Roux-en-Y Gastric Bypass Surgery is reconstructive surgery primarily aimed to treat obesity and associated medical conditions.

Sometimes it is also performed in patients with gastrointestinal malignancies and those with injury to the bile duct and related structures.

When Roux-en-Y Gastric Bypass Surgery is performed for obesity and associated disorders, it is much more modified than the way normal Roux-en-Y Gastric bypass is done for other procedures.

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The main difference is the resection of most parts of the stomach to create a small pouch for food retention.

This form of surgery is malabsorptive because 1 o 2 feet of proximal jejunum is bypassed which reduces the total surface area available for food absorption. Secondly, it reduces the time food interacts and mixes with the digestive juices.

In addition, the volume of the stomach is reduced and the total amount of food that can be stored and accommodated in the stomach is also reduced.

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How Roux-en-Y Gastric Bypass Surgery is performed?

Roux-en-Y Gastric Bypass Surgery is one of the invasive types of bariatric surgery. The procedure involves multiple resections and anastomosis.

Because of the multiple resections and anastomosis, it takes longer than LSG (Laparoscopic Sleeve Gastrectomy).

The patient is fully sedated under general anesthesia. With a standard laparoscope, the stomach is mobilized.

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The stomach is resected leaving only 100 to 200 ml of the stomach volume. A banana-shaped tubular stomach remains.

roux en y gastric bypass
Roux-en-Y Gastric Bypass Surgery

About 2 feet from the duodenojejunal flexure, the jejunum is resected. The distal end of the jejunum is anastomosed with a stomach pouch by a circular stapler while the proximal limb is anastomosed in a side-to-side fashion with the distal limb of the remaining jejunum.

Indications of Roux-en-Y Gastric Bypass Surgery:

Most indications for Roux-en-Y Gastric Bypass Surgery are the same as other Bariatric procedures. These include individuals with a:

  • BMI of more than 40 kg/m²
  • BMI of 35 kg/m² to 40 kg/m² if one or more than one obesity-associated medical conditions are present.

It is important to select the appropriate patients for the procedure to achieve the best results and minimize complications of the procedure.

Which Weight Loss Surgery is the Safest?

The following candidates can undergo a bariatric surgical procedure:

  • Individuals who have failed dietary methods or non-surgical methods to lose weight
    • If a patient is following a strict low-calorie diet, exercises regularly, and fails to lose weight, he/she is a candidate for weight loss surgery.
  • Psychologically stable individuals:
    • Suicidal attempts have been recorded in post-bariatric surgery patients which is why physiologic stability is necessary.

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  • Motivated patient:
    • If the patient is not motivated and does not comply with post-operative instructions or nutritional advice, he/she will regain weight and may be at risk of developing complications.
  • Financially stable to undergo the surgery:
    • As this procedure is costly and will put a lot of financial burden on the patient. That is why financial stability is important.
  • Shall be able to ambulate in the post-op period:
    • If the patient is not able to walk or move around in the postoperative period, the results of the surgery may not be optimal. In addition, the patient may develop complications.
  • Good life expectancy:
    • Individuals with end-stage diseases like liver, heart, and kidney diseases, and those with incurable cancers may not be optimal candidates for weight loss surgery.

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Reasons not to have Roux-en-Y Gastric Bypass Surgery:

There are not many reasons to have bariatric surgery. Some of the contraindications are mentioned here, however, they are contraindications for weight loss surgeries in general and not specific for gastric bypass surgery.

Individuals with an inflammatory gastrointestinal disorder should not undergo bariatric surgery. These conditions may include:

Gastrointestinal Disorders:

  • Severe esophagitis
  • Crohn’s disease
  • Those with stenosis or stricture of the esophageal or intestines, including any contraindications to gastrointestinal surgery.

Individuals with autoimmune diseases and/or steroid use:

  • Systemic lupus erythematosus
  • Scleroderma

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Individuals with advanced organ dysfunction:

  • Decompensated heart failure and reduced life expectancy
  • End-stage renal disease
  • Advanced liver disease
  • Portal hypertension
  • Bleeding varices
  • Gastric Varices
  • Intestinal telangiectasias

Individuals with chronic pancreatitis and alcoholics.

Individuals with a psychiatric disorder:

  • Substance users
  • major depression
  • Psychotic disorders
  • History of suicidal attempts

People who are not willing to comply to post-procedure dietary restrictions, can not mobilize, have a limited life expectancy, and are younger than 18 years of age.

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The effect of Roux-en-Y Gastric Bypass Surgery on obesity-related medical conditions:

Like other bariatric procedures, Roux-en-Y Gastric Bypass Surgery has a tremendous effect on body weight and obesity-associated medical conditions.

Most of the benefits of gastric bypass surgery are because of the weight loss, however, gastric bypass surgery also has direct effects on the body.

This is because the gut is one of the major endocrine organs and bariatric procedures have a significant effect on these gut hormones.

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How much weight can you lose after Gastric Bypass Surgery?

Gastric bypass surgery has superior weight loss effects compared to other bariatric surgical procedures including LSG (laparoscopic sleeve gastrectomy).

It also maintains body weight and minimal regain is observed in the long run. A study was done on 211 patients undergoing this procedure with a follow-up of 10 years.

The majority of the patients had a significant weight loss and the weight loss persisted after 10 years of gastric bypass surgery.

Year after procedure

Excess weight loss

1 year 67.6 +/- 14.9%
2year 72.6 +/- 14.9%
5 year 69.7 +/- 15.5%
8 year 66.8 +/- 7.6%

After 10 years, only 16 patients (14.6%) failed to lose significant weight or regained weight [Ref].

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Diabetes after Gastric Bypass Surgery:

This procedure has been associated with better glycemic control. Even cases of diabetes remission post-surgery have been reported.

Multiple studies have been conducted to assess the effect of Roux-en-Y Gastric Bypass surgery on diabetes.

A study was conducted to assess the effect of Roux-en-Y Gastric Bypass on diabetes and glycemic control.

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In this study total of 1160 patients were included, with a follow-up of 5 years. It showed that Roux-en-Y Gastric Bypass surgery was associated with diabetes resolution in 83% of patients with mild diabetes and with the shortest duration of time [Ref]

The overall effect of LRYGB (Laparoscopic Roux-en-Y Gastric Bypass) Surgery on Diabetes is summarized in the table below:

The effect of LRYGB (Laparoscopic Roux-en-Y Gastric Bypass) Surgery on Diabetes

Diabetes Parameters Before Surgery After Surgery Difference
Mean FBG (Fasting Blood Glucose) 187 100 ⇓ 87
Mean FBG (Fasting Blood Glucose) in patients with severe disease requiring Insulin 187 113 ⇓ 74
Mean FBG (Fasting Blood Glucose) in patients with less severe disease not requiring Insulin 187 86 ⇓ 101
HbA1C 8.2 5.5 ⇓ 2.7
HbA1C in patients with severe diabetes (on Insulin) 8.2 6 ⇓ 2.2
HbA1C in patients with less severe diabetes (not on Insulin) 8.2 5 ⇓ 3.2

It is clear that LRYGB significantly lowered blood glucose by about 100 mg/dl and A1C by more than 2%.

Very few drugs lower the HbA1C to such an extent. Insulin, Semaglutide (Ozempic), and a combination of DPP-IV, metformin, and SGLT-2 Inhibitors can lower blood glucose significantly but even these drugs may not compete with Gastric Bypass surgery.

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Similarly, diabetes was cured in a significant number of patients who had long-standing diabetes. Diabetes in remission is a proper word but patients who had normal blood glucose without requiring any medications even after 10 years may be labeled as cured.

Bariatric surgeons claim that they can cure diabetes. The effect of Gastric bypass surgery on diabetes cure or diabetes remission was seen in a significant number of patients as summarized here:

effect of LRYGB (Laparoscopic Roux-en-Y Gastric Bypass) Surgery on Diabetes

Diabetes Parameters

Before Surgery

After Surgery


Number of patients requiring Insulin 52 11 79% reduction
Total units of Insulin required by the 11 patients who required insulin after surgery 146 45 101 units reduction
Number of patients who were on oral antidiabetic drugs 93 12 81 (87% remission rates)

Of the patients who still required insulin, their total daily requirements of insulin dropped from 146 units per day to 45 units per day.

Out of the 149 diabetic patients who were on oral antidiabetic drugs, only 12 required oral medicines for diabetes control. A significant reduction of 87% was observed.

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The chances of patients who can achieve Diabetes cure or remission depend greatly on the severity and duration of diabetes.

The table below demonstrates the cure rates in diabetic patients according to their diabetes duration:

T2DM resolution based on the duration of diabetes

Diabetes Duration Total Number of Diabetes patients Diabetes Improved Diabetes Resolved
All patients 191 33 158 (82.7%)
Diabetes Duration Less than 5 years 119 6 (5%) 113 (95%)
Diabetes Duration 5 – 10 years 44 11 (25%) 33 (75%)
Diabetes Duration more than 10 years 28 13 (46%) 15 (54%)

It is obvious from the table above that more people with new-onset diabetes can achieve a cure with gastric bypass than those with longstanding diabetes.

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Sleep apnea after Gastric Bypass Surgery:

Like other medical conditions, Roux-en-Y Gastric bypass has a significant role in the resolution of obstructive sleep apnea.

The study was conducted on a total of 39 patients with obstructive sleep apnea. Results were inferred in context with the lowering of the Apnea hypopnea index. A significant improvement in the AHI (Apnea-hypopnea index) was observed post-surgery [Ref].

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Hyperlipidemias after Gastric Bypass Surgery

As it is a known factor that hyperlipidemias are associated with atherosclerosis and coronary heart disease. All bariatric surgical procedures have been found to improve the lipid profile of patients with dyslipidemias.

A retrospective analysis of 95 morbidly obese patients who had Roux-en-Y Gastric Bypass procedures performed were followed for 6 years.

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Results showed the resolution of hyperlipidemias in a significant number of patients [Ref].

The effect of Roux-en-Y Gastric Bypass Surgery in patients with hyperlipidemias after 1 year

Mean Weight Loss 66%
Mean total cholesterol 16%
Mean Triglycerides 63%
Mean LDL 31%
Mean VLDL 74%
Total Cholesterol: HDL 60%
Mean HDL 39%
Patients requiring statins (28) 5 (82%) reduction

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Complications of Roux-en-Y Gastric Bypass Surgery and its management:

Anastomotic stricture:

Stricture formation at the site of anastomosis is a common complication usually seen in gastro jejunostomy anastomosis sites. This can be treated with upper GI endoscopy. If endoscopy fails then the surgical correction will be required.

Anastomotic leaks:

In this case, if the leak is found in gastro jejunostomy then endoscopic repair is possible. If leakage is big or it is in the distal anastomosis then surgical intervention will be necessary.

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Marginal ulcer:

This is a type of gastric ulceration that is found near the anastomosis site of gastro jejunostomy.

It is treated with oral antacids and PPI (proton pump inhibitors) for 14 to 28 days.

Nutritional deficiency:

Gastric bypass is a malabsorptive type of surgery which is why it is associated with nutritional deficiency of macro and micronutrients.

Patients should undergo a nutritional assessment before the procedure. Replacement of vitamins, minerals, and proteins is indicated in all patients.

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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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