Before Surgery

Why Does Weight Loss Surgery Work?

by Brenda Hoehn on Aug 24, 2023

Why Does Weight Loss Surgery Work?

Why Does Weight Loss Surgery Work?

The success of bariatric surgery (also known as weight loss surgery) is sometimes defined as achieving a 50% or more weight loss and maintaining that for at least five years. Studies show that most bariatric patients maintain successful weight loss long-term.

The success behind weight loss surgery is choosing the right procedure for your situation and committing to lifestyle changes like healthy nutrition and exercise.

Types of Bariatric Surgeries

There are different kinds of bariatric surgery, and they work to help people lose weight in three simple ways:

  1. Restrict how much food your stomach can hold at any time (restrictive surgery)
  2. Preventing your digestive system from absorbing all the nutrition in the food you eat (malabsorptive surgery)
  3. A combination of these two

Restrictive Bariatric Surgery

gastric banding

Restrictive weight loss procedures are typically more straightforward and less invasive options since they don’t involve open surgery or the rerouting and reconnecting of the intestines. These bariatric weight loss procedures make less room in the stomach for food after it’s swallowed, and you feel fuller sooner. You also won’t feel as hungry because most of the stomach tissue that secretes the hunger-causing hormone ghrelin will be gone.

Gastric banding, or lap-band surgery, is a common type of restrictive weight loss surgery. During the procedure, an adjustable silicone band is placed around the top end of the stomach to create a small pouch for holding food. Besides making the stomach size smaller, this procedure also slows the passage of the food into the small intestine.

Gastric sleeve surgery, or sleeve gastrectomy, removes 75-90% of the stomach. The edge where the removal happens is stitched or stapled. A “sleeve” of the stomach remains with the muscle that controls emptying food from the stomach into the intestine.

Vertical banded gastroplasty (VBG), or stomach stapling, was a type of restrictive weight loss procedure for reducing food intake that is not commonly used. Following restrictive surgeries, you typically can eat only one-fourth to one-half cup of food at a time without causing discomfort. bariatric surgery for diabetes

Malabsorptive Bariatric Surgery

gastric sleeve

Malabsorptive weight loss procedures shorten or create an intestinal bypass, which alters the process of digestion and reduces the number of calories and nutrients the body absorbs.

Gastric bypass, or Roux-en-Y gastric bypass (RNY), is a type of surgery where the stomach is divided into two sections. The top portion of the stomach becomes a small pouch and serves as the “new” stomach. The middle part of the small intestine (the jejunum) is connected to the “new” stomach. When food is eaten, it enters the small pouch, then travels into the jejunum, bypassing the first part of the small intestine. Because food doesn’t go through the first section of the small intestine, the number of calories and nutrients absorbed into the body decreases. This surgery is both restrictive and malabsorptive.

gastric bypass

The duodenal switch (DS), or biliopancreatic diversion, permanently removes 75-90% of the stomach, creating a “sleeve” or banana-sized pouch, while keeping the basic stomach structure the same. A large portion of the upper intestines is bypassed and reconnected to the stomach. This procedure is malabsorptive.

While the procedures discussed above are the most common, there are other bariatric surgery techniques that surgeons perform. These include:

  • Mini gastric bypass (or minibypass). This procedure was developed to reduce operating time and there is less re-routing of the intestines. Because it’s a fairly new technique, data is being collected to determine if it’s a better procedure than traditional gastric bypass. Typically, this procedure is not covered by insurance.
  • Loop DS or SADI/SIPS. This procedure is a variation (not a substitution) of the duodenal switch (DS) technique. Data for these techniques is being collected about long-term outcomes, complications, and resulting nutritional deficiencies.
  • Gastric balloon. During this procedure, the surgeon places a saline-filled silicone balloon in your stomach. The filled balloon limits how much food can enter the stomach. At this time, the cost for placing and removing the balloon is not covered by insurance. bariatric surgery for diabetes bariatric surgery for diabetes

Lifestyle Changes Have an Impact on Success

In addition to choosing the procedure best for you, bariatric surgery is successful when you are dedicated to the lifestyle changes you committed to making before surgery (see “Is Weight Loss Surgery Right for Me?”) as well as the following factors:

  • Age
  • Preoperative weight
  • Overall health condition
  • Type of surgical procedure
  • Mobility and ability to exercise
  • Dedication to dietary guidelines and follow-up care
  • Motivation
  • Support from family and friends

For many, bariatric surgery and the resulting weight loss become a positive part of their life.

How Does Gut Health Change After Bariatric Surgery?

The bacterial microbes in the human gut perform a range of essential functions in the body, like micro-management of the food you digest. They are central to the regulation of body weight.

After bariatric surgery, microbes that were unable to survive in the obese gut are now able to flourish. Because of this, you may experience increases in microbial diversity and long-term changes in gut bacteria that contribute to immediate and sustained weight loss.

Learn More

If you want to explore the full range of our bariatric vitamin products, please visit our full product listing.