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Vertical Sleeve Gastrectomy How it Works

The vertical sleeve gastrectomy (VSG), which may also be called a sleeve gastrectomy or gastric sleeve, was originally designed to be the first step of a more complex surgical technique. It was found, however, that many patients lost an adequate amount of weight with this single step, never requiring the surgical conversion.

Most patients experience anywhere from a 35-85% loss of excess body weight. On average, weight loss equals approximately 60% of excess body weight after five years.

Sleeve gastrectomy affects weight loss by utilizing two of the four surgical mechanisms in the following ways:

  • Restriction is accomplished by removing 75-85% of the stomach, leaving behind a thin tube (or sleeve) approximately the size of a banana. This banana-sized stomach is approximately three times larger than the pouch of gastric bypass, but still much smaller than the original stomach and also much less flexible. You will feel full after consuming less food.
  • Hormonal changes occur because when the stomach is made smaller, the body produces less of the hormone that triggers the hunger center in the brain. Nearly 75% of patients report decreased feelings of hunger after surgery.

Because the intestines are not disturbed, there is no malabsorption and dumping syndrome is unlikely.

Millie Bariatric

Why Choose Sleeve Gastrectomy?

The sleeve gastrectomy can result in rapid and significant weight loss, leading to:

  • Increased quality of life
  • Drastically improved health, including the resolution of obesity-related diseases, such as sleep apnea, diabetes and hypertension
  • Longer life expectancy

While there is potential for your results to be outstanding, it’s important to keep in mind that the gastric sleeve surgery was originally created as part of a larger procedure. This means that patients who lose less than the expected amount of weight may be considered candidates for a second surgery – most likely a conversion to gastric bypass.


“Because of my weight loss surgery, the life I’m living now is the best I’ve ever lived.”

Lisa Fierce, Bariatric Surgery Patient

Learn more about Lisa’s story here


You’ll often hear the success of a weight loss surgery measured in terms of percentage of excess weight loss (% EWL). In most cases, a surgery is considered successful if it resulted in at least 50% excess weight loss.

If you’d like to keep track of your % EWL at home, the formula is: % EWL = weight lost ÷ excess body weight × 100

For example, suppose an individual is 5’6″ tall and weighs 250 lbs. At this height, an ideal body weight is 150 lbs. This means they have 100 lbs. of excess body weight. If they lose 50 lbs., then their % EWL is:

% EWL = 50 lbs. (weight lost) ÷ 100 lbs. (excess body weight) × 100%
% EWL = 0.5 × 100%
% EWL = 50%


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