Gastric Bypass*


How the Gastric Bypass Operation Works*

The primary means by which the Gastric Bypass operation works is by restricting the amount of food that can be eaten at a single meal. The small gastric pouch varies somewhere between 15 and 30 ccs in size. This amounts to only a few ounces of solid food at a time. Eating too much volume will produce discomfort and eventually vomiting, both of which reinforce eating small amounts of food slowly.

In addition, because the first part of the small intestine (duodenum) is bypassed, along with the distal stomach, the digestive juice does not reach the food until the connection at the “Y”. This has particular importance for sugar intake, because sugars require enzymes from the pancreas to be broken down for absorption. A high concentration of sugars in the small intestine which are not absorbed lead to the Dumping Syndrome. This is a combination of flushing, cramping and diarrhea, often as a severe brief episode. Sugar intake, particularly processed sugars, must be restricted after Gastric Bypass or the patient will suffer from the Dumping Syndrome.

Finally, since no food will pass through the distal stomach and proximal intestine there is very little stimulation for the production of most intestinal hormones. Intestinal Hormones are chemicals produced by the intestinal tract that are excreted into the blood stream and cause effects remote from the intestine (e.g. insulin). Some of the hormones have an effect on how the brain perceives hunger. For example, Graylin, an Intestinal Hormone thought to drive hunger, stays at a very low level after Gastric Bypass. As a result, most patients do not suffer wide swings in hunger shortly after eating, and the drive to eat is generally diminished.

Why a Gastric Bypass Operation May Be Right For You

Because of a combination of the above factors the Gasrtric Bypass operation has demonstrated excellent weight loss for almost all patients. Its reliability has made the Gastric Bypass the Gold Standardweight loss surgery in the United States.

Laparoscopic Roux-en-Y Gastric Bypass

Fact Sheet

Laparoscopic surgery – not open
Several (5) small scars
Less pain than open surgery
Quick recovery

  • Immediate activities of daily living
  • Return to work 7-10 days
  • No lifting > 20 lbs or strenuous activity 3 weeks

Create a small gastric pouch from the upper stomach (separating the distal stomach). Then divide the small intestine. Connect the downstream end to the little pouch. Connect the upstream end into the side of the downstream limb (make the Y).

BMI 35-40 with comorbidities

  • Diabetes
  • High blood pressure
  • High cholesterol or triglycerides
  • Obstructive sleep apnea
  • Family history of heart disease or stroke

BMI > 40 with or without comorbidities
Very good for Diabetes – should be an option for all type 2 diabetics
Antireflux – should be an option for all patients with Barrett’s Esophagus or severe GERD

Deformity or pathology of the esophagus or stomach – e.g. esophageal stricture
Previous gastric surgery – e.g. Nissen fundoplication
Previous intestinal surgery or open abdominal operations with the potential for major adhesions

Surgical risk
Limited missed work
Difficult to reverse
Difficult to revise to another procedure

Low sugar clear liquids 4 hours -7 days
Low sugar low fat soft diet 7-28 days
Low sugar low fat high protein diet after 28 days

Reversible with difficulty and increased risk
Only justified in a few scenarios with rare long-term post-operative problems


  • Transfusion < 0.5%
  • Re-operation primarily limited to endoscopy

Leak with peritonitis (re-operation) < 0.5%
Narrowing requiring endoscopy with balloon dilation – rare
Marginal ulceration at upper connection site

  • Risks include – smoking, pain meds, alcohol
  • Treated with medications
  • Recurrent or non-healing – laparoscopic revision or reversal

Bowel obstruction or internal herniation

  • Rare life-long risk
  • Can require laparoscopy to diagnose and treat

Vitamin and mineral deficiencies – rare except for B12 and iron

Patients start an exercise program before LSG
Interruption approx. 3 weeks by procedure
Minimum of 150 minutes a week of some activity

  • Measure the exercise – steps/distance/time
  • Set goals
  • Exercise with someone else – family, co-worker

General Anesthesia in Operating Room
50-70 min
Recovery with Overnight Stay

Eat less*
Feel full faster*
Less hunger due to favorable effect on intestinal hormones*
Weight loss*

* Results will vary by person and are based upon the patient, the surgery type and the compliance with the aftercare program. As with any medical procedure or surgery, there are specific risks and possible complications. The testimonials, statements, and opinions presented on our website are applicable to the individuals depicted. Results may not be representative of the experience of others. Testimonials are voluntarily provided and are not paid, nor were they provided with free products, services, or any benefits in exchange for said statements. The testimonials are representative of patient experience but the exact number of pounds lost and experience will be unique and individual to each patient.

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