Gastric Bypass vs. Mini Gastric Bypass

RNY Gastric Bypass vs Mini Gastric Bypass Surgery Comparison

When choosing the best bariatric surgery option, Roux-n-Y gastric bypass (RNY) and Mini Gastric Bypass (MGB) are high-quality and effective procedures. They provide significant and permanent weight loss in a short period of time by restricting the amount of food you can eat and reducing the number of calories absorbed. Obesity-related metabolic disorders, such as diabetes, are also cured completely or alleviated with these two surgeries.

In mini bypass, there is only one intestinal rerouting and it is a quicker operation. As a result, the risk of complications goes down with MGB compared to traditional bypass. Both procedures diminish GERD/Reflux symptoms at one-year post-op.

In order to choose your most suitable operation, it’s critical to understand the pros and cons of both surgeries. This article will explain the significant benefits, similarities, differences, and results that patients can expect from gastric bypass surgery and one-anastomosis gastric bypass surgery.

Mexico Bariatric Center®‘s surgical teams can help you find the best option!

Past Patients Rena & Sarita explain Mini Bypass vs. RNY Bypass

Procedures Explained: Pros and Cons

RNY Gastric Bypass Surgery - Gastric Bypass vs Mini Gastric Bypass

RNY Gastric Bypass

In this established procedure, the surgeon forms a stomach pouch, approximately 5-10% of the original stomach size while keeping the separated excess stomach in place to aid indigestion.

Mini Gastric Bypass Surgery - Mini Gastric Bypass vs Duodenal Switch

Single Anastomosis Gastric Bypass

In this newer operation, the surgeon forms a tube-shaped stomach pouch that holds approximately 4 to 6 ounces of food. Bypasses an average of 20% of the small intestine.

Which Procedure is Best For You?

Traditional Roux-n-Y Gastric Bypass and Loop (“Mini”) Gastric Bypass are valuable options as primary procedures as well as revisional of failed primary restrictive procedures for morbidly obese. Mini Bypass with one fewer intestine connections is less invasive with more infrequent side effects and complications. Mexico Bariatric Center offers both options at a discounted price with over 60% savings.

  • Highest Amount of Excess Weight Loss (%EWL) – RNY Gastric Bypass
  • Less Invasive Surgery – Mini Gastric Bypass
  • Low Complication Rate – Mini Gastric Bypass
  • Less Number of Potential Side Effects – Mini Gastric Bypass
  • Lowest Cost of Procedure –  Cost of Mini Bypass and Gastric Bypass Surgery in Tijuana, Mexico are pretty similar
  • Highest Reduction in Comorbidities and Health-Related Problems – RNY Gastric Bypass
  • Most Popular Surgery: RNY Gastric Bypass
  • Most Effective Conversion from Failed Gastric Sleeve – Mini Gastric Bypass*

* There is a higher chance of symptomatic (bile) reflux when revising from sleeve to mini bypass

Find Out if You Qualify For Gastric Bypass or Mini Gastric Bypass Surgery

Take Away

Roux-en-Y bypass is recognized as the “gold standard” of bariatric and metabolic surgical treatment of obesity. It has been around since 1967 with slight variations. RNY bypass has a long-term and well-documented track record.

Thousands of mini bypass surgeries have been performed successfully worldwide since Dr. Rutledge invented this procedure in 1997.  However, the bariatric community is still divided over the validity of this procedure and its possible side effects:

  • bile reflux
  • marginal ulcer
  • malnutrition
  • oesophageal cancers

Mexico Bariatric Center’s surgical team has expertise in mini gastric bypass as a stand-alone option or as a revision of previous surgeries to treat obesity disease.

Gastric Bypass Surgery vs Mini Gastric Bypass Surgery Infographic

Gastric Bypass vs Mini Bypass: Table Comparison

Type of Surgery

Gastric Bypass

Mini Gastric Bypass

Method of Weight Loss

Restrictive & Malabsorptive

  • New Stomach Created
  • Alters Digestion
Restrictive & Malabsorptive

  • New Stomach Formed
  • Alters Digestion

Stomach Alterations

New stomach created: Stoma

  • The stomach is bypassed, with a new smaller stomach (stoma) created with intestines.
New stomach formed

  • The stomach is turned into a tube-shaped, with a new smaller stomach (stoma) created with intestines.

Changes to Intestine

Cut and Bypassed

  • The stoma is rerouted to bypass a large portion of intestines. This reduces absorption of nutrients and calories.
Cut and Bypassed

  • The stomach uses a single connection to the small intestine, known as single anastomosis.

Operating Time

  • 2 hours
  • 1.5 to 2.5 hours

Average Hospital Stay

  • 2 to 3 nights
  • 2-3 nights

Time off Work

  • 2 to 3 weeks
  • 2 to 3 weeks

Recovery Time

  • 3 weeks
  • 3 weeks


  • High Expected Weight Loss, Comparable to Duodenal Switch.
  • Gastric Bypass has been performed hundreds of thousands of times. Thus, side effects and complications are known.
  • High excess weight loss
  • Low-risk procedure in comparison to Gastric Bypass


  • Major and complicated surgery with associated risks.
  • Leakage, bleeding, vomiting can occur.
  • Daily supplements and vitamins needed.
  • Dumping syndrome is common.
  • Newer Procedure
  • Less long-term results as Gastric Bypass
  • Vitamins and supplements needed.

Surgery Description

Small pouch (about 1 oz/15-30 cc) Pouch is connected to the small intestine where food and digestive juices are separated for the first 3 to 5 feet. The RNY significantly restricts the volume of food that can be eaten.

Small tube-like stomach (about 2 to 3 oz/25 to 45 cc) is connected to the small intestine where food and digestive juices are separated for the first 4 to 6 feet.

Realistic Expectations

  • Provides mild malabsorption of nutrients
  • Patients can expect to lose 70% of excess weight.
  • Less than patients with Duodenal Switch.
  • Provides mild malabsorption of nutrients
  • Patients can expect to lose an average of 76% of excess weight
  • Less than patients with Duodenal Switch

Post Surgery Dietary Info

  • Patients must eat three small meals a day.
  • Patients must avoid sugar and fats to prevent Dumping Syndrome.
  • Patients must take vitamin and protein supplements to avoid deficiency (Multivitamin, Calcium, Vitamin B12, and Iron for menstruating women)
  • Bypass patients need to be on vitamins for the rest of their life to aid in digestion


Gastric Bypass is effective for patients with a BMI of 35-55 and those with a “sweet tooth.”

The new stomach will hold about 2 to 3 ounces of food instead of the average 40 ounces.

The mini bypass is less complicated than the RNY because of only one connection to the intestines.

2-Year Follow-Up

  • Patients maintained a 67% loss of excess body weight.
  • Nearly 20% of patients had failed to lose at least 50% of their excess weight.
  • Patients maintained a 65% loss of excess body weight.
  • A rather new procedure with less long-term weight loss data