The oldest form of bariatric bypass surgery is the most familiar, stomach stapling. In this 30-year-old form of bariatric bypass surgery, most of the stomach is cut and then stapled shut so that only a small pouch remains. After the stomach is made smaller, the person is not able to eat as much food - at least in terms of volume of food.
With a smaller stomach, it takes far less food to feel full, usually the amount of food that you could put on a coffee saucer. It becomes impossible to eat more than two quarter-cup servings of anything at a single meal. Weight loss follows calorie restriction.
The newer and now more common form of bariatric bypass surgery, the Roux-en-Y gastric bypass, also makes the stomach surgically smaller, but the stomach is not cut and stapled.
In Roux-en-Y gastric bypass the stomach is cut and sutured, or sewn, and the intestines are moved so that the end of the stomach is connected farther down the intestine.
In Roux-en-Y bariatric surgery, there's a smaller stomach that fills more quickly. There's also less intestine to absorb fats (and other nutrients) from the smaller amounts of food that are eaten.
With this form of bariatric surgery, you don't just eat less. You absorb less of the food you do eat. Roux-en-Y bariatric surgery produces faster and greater weight loss than just stapling or banding the stomach.
There's also a third approach to bariatric bypass surgery, the lap band.
The advantage of the lap band is that the bariatric bypass surgery to install it can be laparoscopic, that is, done through an incision as little as one inch (2.5 cm) wide.
Lap band bariatric bypass surgery can even be an outpatient procedure, with the patient going home the same day, going back to work in three days, and going about all normal activities - except eating - within a week. Other forms of surgery require a minimum of four days in the hospital and six to eight weeks to resume normal activities.
With the lap-band the surgeon is placing something around the outside of the stomach. The bacteria in the stomach do not leak into other parts of the body, and the risk of infection is greatly reduced.
The lap band procedure is much less painful. Because the pain in the muscles is so much less, patients are very unlikely to develop pneumonia or other breathing problems.
The disadvantage of lap band bariatric surgery is that not everyone can have it. The FDA requires that recipients of lap band bariatric procedures be between 18 and 51 years of age. They must not have any autoimmune diseases that would cause their bodies to reject the plastic band.
And if you overeat after you have a lap band in place, the effect is a little like pulling a napkin through a napkin ring. Too much food can stretch the band so that it damages the stomach.
No form of bariatric bypass surgery is a complete cure for obesity. Lifetime diet and exercise are still necessary. But successful bariatric bypass surgery can give you the boost you need to regain control of your life and become truly, lastingly, healthily thin.