Bariatric surgery was originally developed under the assumption that restriction and malabsorption lead to the desired weight reduction. In the meantime, these explanatory approaches have become obsolete, as changes in hormonal regulation, intestinal flora and bile acids have a strong influence on the feeling of hunger and satiety during weight reduction.
Restriction
The restriction means that the capacity of the stomach is reduced and a narrowing of the passage to the rest of the digestive tract is created. The principle of sole restriction is given in gastric banding. Gastric banding gives the stomach a "waist" that separates a small part of the stomach from the remaining stomach. The constriction can be easily passed by liquid food. Solid food, on the other hand, lingers longer in the small part of the stomach, resulting in a longer lasting feeling of satiety, which already occurs with small food amounts. Effects in the sense of malabsorption do not occur with gastric banding.
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| https://magenverkleinerung.tips/, Gastric banding Icon, CC BY-SA 4.0 |
Another restrictive procedure is gastric sleeve procedure, in which part of the stomach is permanently removed. This procedure can achieve a considerable reduction in weight. However, this is not exclusively due to a restrictive effect, but also to a change in the formation of gastrointestinal hormones. According to scientific studies, pure restriction for weight reduction even seems to be of secondary importance in the case of gastric sleeve procedure.
Malabsorption
The principle of malabsorption is based on a delayed combination of food and digestive juices, primarily pancreatic and bile secretions, which reduce the absorption of fat-bearing food. A classic example of a malabsorptive procedure is biliopancreatic diversion according to Scopinaro.
The biliopancreatic diversion leads to the strongest weight reduction in comparison with all other bariatric surgical techniques due to the significant lack of digestion. This may be useful for extreme obesity, but it has its price. Malabsorption leads to a severe loss of nutrients and can result in massive diarrhoea. A consistent supplementation of micro- and macronutrients is necessary as well as a lifelong aftercare with regular laboratory controls.
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