Weight-loss Surgery : Bariatric
Exercise and diet alone often fails to effectively treat people with extreme and excessive obesity.
Bariatric surgery is an operation that is performed in order to help such individuals lose weight. Evidence suggests that bariatric surgery may lower death rates for patients with severe obesity, especially when coupled with healthy eating and lifestyle changes after surgery.
Body Mass Index (BMI)
Body Mass Index (BMI), a measure of height in relation to weight, is used to define levels of obesity and help determine whether bariatric intervention is required. Clinically severe obesity describes a BMI of over 40 kg/m2 or a BMI of over 35 kg/m2 in combination with severe health problems.
Health problems associated with obesity include Type 2 Diabetes, Arthritis, Heart disease, and Severe Obstructive Sleep Apnea. The experts approve the use of adjustable gastric banding for patients with a BMI of 30 kg/m2 or more who also have at least one of these conditions.
Principles of Bariatric Surgery
The basic principle of bariatric surgery is to restrict food intake and decrease the absorption of food in the stomach and intestines.
The digestion process begins in the mouth where food is chewed and mixed with saliva and other enzyme-containing secretions. The food then reaches the stomach where it is mixed with digestive juices and broken down so that nutrients and calories can be absorbed. Digestion then becomes faster as food moves into the duodenum (first part of the small intestine) where it is mixed with bile and pancreatic juice.
Bariatric surgery is designed to alter or interrupt this digestion process so that food is not broken down and absorbed in the usual way. A reduction in the amount of nutrients and calories absorbed enables patients to lose weight and decrease their risk for obesity-related health risks or disorders. Bariatric surgery contributes to weight loss in two main ways:
- Restriction : Surgery is used to physically limit the amount of food the stomach can hold, which limits the number of calories you can eat.
- Malabsorption: Surgery is used to shorten or bypass part of the small intestine, which reduces the amount of calories and nutrients the body absorbs.
Four common types of weight-loss surgery are:
- Roux-en-Y Gastric Bypass
- Laparoscopic Adjustable Gastric Banding
- Sleeve Gastrectomy
- Duodenal Switch with Biliopancreatic Diversion
1. Roux-en-Y Gastric Bypass
In Roux-en-Y gastric bypass, the surgeon creates a small pouch at the top of the stomach. The pouch is the only part of the stomach that receives food. This greatly limits the amount that you can comfortably eat and drink at one time.
The small intestine is then cut a short distance below the main stomach and connected to the new pouch. Food flows directly from the pouch into this part of the intestine. The main part of the stomach, however, continues to make digestive juices. The portion of the intestine still attached to the main stomach is reattached farther down. This allows the digestive juices to flow to the small intestine.
Because food now bypasses a portion of the small intestine, fewer nutrients and calories are absorbed.
2. Laparoscopic Adjustable Gastric Banding
In the laparoscopic adjustable gastric banding procedure, a band containing an inflatable balloon is placed around the upper part of the stomach and fixed in place. This creates a small stomach pouch above the band with a very narrow opening to the rest of the stomach.
A port is then placed under the skin of the abdomen. A tube connects the port to the band. By injecting or removing fluid through the port, the balloon can be inflated or deflated to adjust the size of the band.
Gastric banding restricts the amount of food that your stomach can hold, so you feel full sooner, but it doesn’t reduce the absorption of calories and nutrients.
3. Sleeve Gastrectomy
In a sleeve gastrectomy, part of the stomach is separated and removed from the body. The remaining section of the stomach is formed into a tube like structure. This smaller stomach cannot hold as much food. It also produces less of the appetite-regulating hormone ghrelin, which may lessen your desire to eat. However, sleeve gastrectomy does not affect the absorption of calories and nutrients in the intestines.
4. Biliopancreatic Diversion With Duodenal Switch
As with sleeve gastrectomy, this procedure begins with the surgeon removing a large part of the stomach. The valve that releases food to the small intestine is left, along with the first part of the small intestine, called the duodenum. The surgeon then closes off the middle section of the intestine and attaches the last part directly to the duodenum. This is the duodenal switch.
The separated section of the intestine isn’t removed from the body. Instead, it’s reattached to the end of the intestine, allowing bile and pancreatic digestive juices to flow into this part of the intestine. This is the biliopancreatic diversion. As a result of these changes, food bypasses most of the small intestine, limiting the absorption of calories and nutrients. This, together with the smaller size of the stomach, leads to weight loss.
Surgical and Post-Operative Risks
People who have had Bariatric Surgery need to adhere to a rigorous and lifelong diet and exercise plan to prevent complications and to avoid putting on weight after surgery. In addition, patients may develop excess loose and folded skin that requires further surgery to remove and tighten.
As with all types of surgery, bariatric surgery is associated with risks including internal bleeding, deep vein thrombosis, infections, and pulmonary embolism (blood clot in the lungs). It is estimated that the risk of dying shortly after bariatric surgery is around 1 in 200.
Bariatric Surgery Not Always Works
Studies show that many people who have bariatric surgery lose about 15 to 30 percent of their starting weight on average, depending on the type of surgery they have. However, no method, including surgery, is sure to produce and maintain weight loss. Some people who have bariatric surgery may not lose as much as they hoped. Over time, some people regain a portion of the weight they lost. The amount of weight people regain may vary. Factors that affect weight regain may include a person’s level of obesity and the type of surgery he or she had.
Bariatric surgery does not replace healthy habits, but may make it easier for you to consume fewer calories and be more physically active. Choosing healthy foods and beverages before and after the surgery may help you lose more weight and keep it off long term. Regular physical activity after surgery also helps keep the weight off. To improve your health, you must commit to a lifetime of healthy lifestyle habits and following the advice of your health care providers.