How does Roux-en-Y gastric bypass surgery help a person lose weight?
• Gastric restriction. The small stomach pouch created during surgery can hold only about two to four tablespoons (three ounces) at a time. In addition, the connection between this pouch and the jejunum is approximately 1.0 to 1.5 centimeters (1/3 to 1/2 inch) in diameter. Both of these factors drastically reduce the amount of food that can be eaten at one time. • Nutrient malabsorption. Normally, the body absorbs calories and nutrients at all stages of digestion. With two of these stages bypassed, the body has less opportunity to absorb digestive material. The fewer calories the body can absorb, the greater the weight loss. • The “dumping syndrome.” Many gastric bypass patients become less tolerant of foods high in refined sugar and fats. This is because these types of foods enter the small intestine very quickly (the dumping syndrome), and in some patients, may cause symptoms such as nausea, weakness, dizziness, and sweating.
