How Weight Loss Surgery
Works
To understand how gastric bypass surgery
helps to reduce obesity, we need to know how we normally digest our food.
Fig 1. The Normal Digestive Process
As food moves along the digestive tract,
digestive juices and enzymes digest and absorb calories and nutrients.
For example, as we chew and swallow our food, it proceeds downwards along
the esophagus to the stomach, where powerful stomach acids continue the
digestive process. The stomach can hold about 3 pints of food at one time.
As the partially digested stomach contents move to the duodenum, (the
first segment of the small intestine), bile and pancreatic juice speed
up digestion. Most of the iron and calcium in the foods we eat is absorbed
in the duodenum. The jejunum and ileum, the remaining two segments of
the nearly 20 feet of small intestine, complete the absorption of almost
all calories and nutrients. The food particles that cannot be digested
in the small intestine (eg. fiber) are stored in the large intestine until
eliminated.
How Does Weight Loss Surgery Promote Weight
Control?
Restrictive Weight Loss Surgery
Gastrointestinal weight loss surgery alters the normal digestive process.
It closes off parts of the stomach to make it smaller. Operations that
only reduce stomach size are known as “restrictive operations”
because they restrict the amount of food the stomach can hold.
Malabsorptive Weight Loss Surgery
Some operations combine stomach restriction with a partial bypass of the
small intestine. These procedures create a direct connection from the
stomach to the lower segment of the small intestine, literally bypassing
portions of the digestive tract that absorb calories and nutrients. These
are known as malabsorptive operations.
Benefits and Health Risks of Weight Loss
Surgery
Malabsorptive operations produce more weight
loss than restrictive operations, and are more effective in reversing
the health problems associated with severe obesity. Patients who have
malabsorptive operations generally lose two-thirds of their excess weight
within 2 years. But malabsorptive operations also carry greater risk for
nutritional deficiencies. This is because the procedure causes food to
bypass the duodenum and jejunum, where most iron and calcium are absorbed.
Menstruating women may develop anemia because not enough vitamin B12 and
iron are absorbed. Decreased absorption of calcium may also bring on osteoporosis
and metabolic bone disease. Patients are required to take nutritional
supplements that usually prevent these deficiencies.
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Weight
Loss Surgery Information
How
Weight Loss Surgery Works - Morbid
Obesity - Morbid
Obesity Surgery
Treatment of Obesity
- Bariatric
Surgery Health Risks - Abdominoplasty
Gastric Banding - Gastric
Bypass - Mini
Gastric Bypass - Gastroplasty
Laparoscopic
Gastric Bypass - Roux
En Y Gastric Bypass - Lap
Band Surgery
Lap Band - Lap
Band FAQs - Biliopancreatic
Diversion - Duodenal
Switch
Liposuction - Liposuction
Surgery - Superwet
Liposuction - Tumescent
Ultrasonic Liposuction
- Tummy Tuck - Mini
Tummy Tuck - Stomach
Stapling
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