The procedure

Obesity surgery reduces excess weight by responding to the energy balance:

  • Reducing food intake: a restrictive procedure
  • Adjusting food absorption or digestion: a malabsorptive procedure
  • A combination of both: a restrictive as well as a malabsorptive procedure

Restrictive procedures

Restrictive procedures serve to evoke a faster feeling of satisfaction. As soon as we experience a feeling of satisfaction during dinner, our sense of hunger disappears, causing us to eat less. The surgeon makes a small reservoir in the upper part of the stomach. The reservoir has a capacity of about 15 to 30 ml and is connected to the rest of the stomach by a small opening. Due to this reservoir, there is a reduced intake of food causing the patient to feel satisfied sooner. The digestion (absorption) of food in the colon remains unchanged. This technique requires the patient to be motivated enough to adapt to a new way of eating: eating slower, chewing well and avoid high-fat or high-calorie drinks or snacks. The procedure can fall short of its objective if the guidelines aren’t strictly followed by the patient. The stomach reservoir and/or the constriction may expand, making the energy intake too high after all.


  • Gastric banding or the adjustable lap-band: the level of restriction is adjustable afterwards and the procedure is reversible.
  • Vertical gastroplasty: the level of restriction is not adjustable, and the procedure is virtually irreversible.
  • Sleeve gastrectomy: this procedure is irreversible.

Malabsorptive procedures

Malabsorptive procedures influence digestion, causing food to digest poorly and to not be fully absorbed. The anatomy of the small intestine is modified in order to divert bile and pancreatic juice, as to only come into contact with the ingested nutrition at the end of the small intestine. The late blending of food with bile and pancreatic juice hinders the absorption of fat and carbohydrates. The surgeon can adjust the length of the shared intestinal loop to adjust the level of absorption of protein, fat and fat-soluble vitamins.


  • Biliopancreatic derivation (BPD) or Scopinaro.
  • Sleeve gastrectomy with duodenal switch: BPD variation, reducing the stomach in a different way.


When surgeons combine restrictive and malabsorptive procedures, a stomach reservoir (15 ml) is formed using surgical staples. The rest of the stomach is not removed, but completely closed off from the upper part of the stomach. This part remains hemorrhagic and therefore vital. The small stomach reservoir is directly bypassed to a lower part of the small intestine, which is, hence, cut and pulled completely upwards. This intestinal loop is then reconnected to the ‘original’ small intestine at a lower point, causing the absorption of nutrients to be blocked in the duodenum. Therefore, digestion will only start in a later section of the colon. The length of each section of the colon can vary, creating a lower or higher level of absorption. The connection between the small stomach reservoir and the elevated small intestine is intentionally kept relatively narrow. This, together with the small volume of this piece of stomach, causes the restrictive effect – arguably the most important effect of this procedure.



  • Gastric bypass: this is the most commonly performed procedure and is considered the golden standard when it comes to durable weight loss and preservation of quality of life.

Gastric bypass

A gastric bypass leads the food around the stomach. It is one of the most common procedures.

Read more here

Gastric sleeve

In a gastric sleeve procedure, the surgeon removes up to 80 percent of the stomach from the body. A narrow, tubular stomach remains.

Read more here

Gastric banding

In a gastric banding procedure, an elastic band is placed around the upper part of the stomach. This procedure is reversible.

Read more here

Possible procedural risks

Bariatric surgery can lead to spectacular results. Nevertheless, there are also potential risks and complications involved, as is the case with all surgical procedures.

Read more here

Potential results

Losing your excess weight is just the beginning. Did you know, for example, weight loss has a positive influence on afflictions such as asthma, sleep apnea and depression?

Read more here

Dr. Yannick Nijs contact | Obesity Centre Brussels

Dr. Yannick Nijs
Obesity surgeon

St-Michel Europe Hospitals
150 Linthoutstraat, 1040 Brussels

+32 470 588 537
+32 2 614 37 20

Contact usMake an appointment