Gastric bypass surgery makes your stomach smaller. This causes you to feel full with less food so you consume fewer calories. The procedure also bypasses part of your small intestine, so fewer calories are actually absorbed into your system. Fewer calories will ultimately lead to weight loss.

When you eat food, it passes through the esophagus and enters into the stomach, where gastric acids soften the food and begin to dissolve it. Next, this semi-liquid mixture enters into the small intestine, where most of the calories and essential nutrients are absorbed by your body. Finally, whatever is left passes into the large intestine and eventually through the colon as it is expelled from the body. Gastric bypass surgery restructures the stomach and intestinal system, resulting in intentional malabsorption and limiting the patient