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Gastric Bypass Surgery > How Gastric By-pass Surgery Works

This procedure results in a combination of 2 weight-loss mechanisms

  • The primary mechanism is mechanical restriction, by virtue of the creation of the 25 mL upper gastric pouch. The operation restricts food intake very effectively, particularly during the first year, the time of maximum weight loss. Ultimately a bypass patient will be able to eat about a cup of food per meal three times a day, experiencing prolonged satisfaction and fullness from that amount of food while losing weight. Hunger and cravings are controlled, particularly if the patient is compliant. This is a profound experience for many, being released from a prison of hunger.
  • The secondary mechanism is malabsorption: the Roux limb delays the mixing of the nutrients with the biliary and pancreatic juices while preserving the entero-hepatic cycle of the bile salts. By bypassing parts of the intestine, food is now delayed from mixing with the digestive enzymes. The food is now not digested completely and the food that is digested has less time to be absorbed because there is less bowel to absorb it. The digestion of food starts later than normal, thus less food will be digested. The point where the biliopancreatic limb is connected to the food conducting limb can vary to produce more or less malabsorption. More bypassed bowel increases risk and side-effects.

Surgery alone will not ensure long-term success. Surgery is a great tool, something to help patients do the work, to reach their health and weight loss goals. The operation will help and to a degree force patients to change their eating habits for life.

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