Gastric Bypass

A gastric bypass is a surgery where the stomach is reduced and a small part of the digestive tract is diverted. Gastric bypass is therefore a combined procedure which aims a limited food intake and a reduced food absorption.

During the surgery, a small gastric pouch is separated from the stomach at the entrance of the stomach. This gastric pouch has the volume of two fingers. The rest of the stomach just stays in place. The small gastric pouch is then connected to the small intestine usually with staples, reducing the size of the stomach which leads you to eat less and absorb less food.

Due to the reduced absorption of foods and the vitamins they contain, daily intake of multivitamin is necessary after this kind of surgery, especially in the first 6 months after the procedure.

After this procedure, you should strongly limit the consumption of sugars and alcohol, as you may experience symptoms of gastric dumping. This side effect may be a feeling of dizziness even with sweating, palpitations and in exceptional cases diarrhea. With alcohol consumption, you should consider that you get drunk much faster.

A variant of the gastric bypass is the “banded gastric bypass”.

This procedure is identical with the only difference is that a ring is placed around the pouch to prevent its expansion.



Studies with numerous patients have shown that patients loose  on average in 77% of their excess weight after a gastric bypass. For example, for an obese patient with an overweight of 50 kg, this means a weight loss of 38 kg after 1 year.

Ten years following the procedure there is still an average loss of overweight of 60%. This is mainly due to the diet of the patients and therefore the result can be very different from one person to another.

Evolution of weight loss after gastric bypass

This graph compares the results after a gastric bypass and the banded gastric bypass. The standard gastric bypass still has acceptable results after 5 years but is inferior to the banded gastric bypass which results in a more stable weight loss.

Other beneficial effects:

Over 90% of comorbidities (disorders due to obesity) disappear or improve as a result of this procedure: high blood pressure, type II diabetes, back pain, sleep apnea, depression and others.

Comorbidities resolved or improved after gastric bypass.

Advantages of gastric bypass :

  • A gastric bypass is reversible.
  • Early feeling of satiation while eating
  • Decreased feeling of hunger in the first months or even years after the procedure.
  • Dumping: these are complaints that occur immediately after a meal and can include sweating, palpitations and nausea. These complaints are mainly triggered by the consumption of sugars, the consumption of alcohol or eating too quickly. As a result, patients will avoid these behaviors and eat more slowly, which will lead to better weight loss.
  • Fast thinning with an average loss of ¾ of overweight. Weight loss stops after 1 to 1,5 years depending on your obesity.
  • High blood pressure, diabetes and high cholesterol will improve. Diabetes and sleep apnea can even fade away. You have more energy and build a stronger self-image.
  • Your libido increases.
  • Your quality of life improves.

Disadvantages of gastric bypass :

  • Dumping: sometimes dumping can have such an impact that patients lose too much weight.
  • Vitamin deficiency can occur in the medium term.
  • For this reason, regular monitoring is important. During this visit, we will ask questions regarding your condition and check your blood values. These check-ups are as important as your weight loss!