What Is Obesity?
Obesity is the result of excessive accumulation of fat beyond the body’s requirements. According to the National Institute of Health (NIH), health problems are associated with weighing 20% more than one’s ideal body weight. The most accurate way to quantify "obesity" is by associating an individual's weight with his/her height. This relationship is known as Body Mass Index (BMI). BMI is calculated by dividing actual body weight (measured in pounds or kilograms) by height (expressed as square meters or square inches). According to the National Heart, Lung, and Blood Institute (NHLBI), a BMI between 18.5 and 25 Kg/m2 is considered to be within the normal range. Individuals with BMI’s between 25 and 29.9 kg/m2 are considered overweight and those with BMI’s between 30 and 39.9 Kg/m2 are considered obese. Morbid obesity is defined as body weight greater than 100 lbs above the ideal body weight, BMI of 40 Kg/m2 or BMI of 35 Kg/m2 when associated with other health problems or co-morbidities. Currently, more than 50% of Americans are considered overweight and more than 5 million are considered morbidly obese. Furthermore, childhood obesity is becoming an epidemic in the United States.
What Causes Morbid Obesity?
It would not only be simplistic but probably erroneous to explain obesity as the result of overeating. The medical literature has shown that there are multiple, complex factors that contribute to weight gain, which include genetic predisposition, environmental factors, lifestyle, psychological factors and specific hormones (leptine and Ghrelin).
What are the Dangers of Being Obese?
Research has shown that the risk for developing health problems such as heart attack, Type 2 Diabetes, hypertension and dyslipidemia, sleep apnea, menstrual problems, infertility, urinary stress, gastroesophageal reflux disease and depression increases with increasing BMI. In fact, patients whose weight exceeds twice their ideal body weight have double the risk for an early death compared to non-obese individuals. Obesity has been correlated with increased mortality associated with several cancers, including endometrial (5.4 times), gallbladder (3.6 times) uterine/cervix (2.4 times), prostate (1.3 times) and colorectal (1.7 times) cancer (5). In addition, the social, psychological and economic effects of morbid obesity can be especially devastating for the individual and his/her family. Importantly, studies have shown that weight loss can reduce obesity-related health risks. For example, a 10% weight reduction results in a 20% reduction in the risk for developing coronary heart disease.
What Treatments are Available for Obesity?
Currently, several treatment options are available to “fight” obesity.
Dietary Therapy:
The objective of all diets is to customize caloric intake to individual needs. It is important to realize that reducing calories should be done in a slow and methodic fashion. Rapid, unsupervised weight loss is associated with serious deleterious effects to the body such as malnutrition and metabolic disorders.
Physical Activity:
A sedentary lifestyle and lack of exercise are major contributors to obesity. Physical activity is necessary to maintain weight loss. Regular exercise re-sets the internal “thermostat” to a higher metabolic steady state, enhancing calorie and fat burning.
Thirty minutes or more of daily physical activity is recommended to maintain or control weight
Drug Therapy:
Drug therapy is usually reserved for individuals with a BMI greater than 30 Kg/m2 or greater than 27 Kg/m2 with co-morbidities (hypertension, dyslipidemia, sleep apnea and type 2 diabetes). In order to avoid health problems such as malnutrition, any patient participating in a drug therapy regimen must be assessed at regular intervals by the medical team. Currently, the US Food and Drug Administration (FDA) has approved three drugs for the treatment of obesity: Orlistat (Xenical), Phentermine and Sibutramine (Meridia). These drugs act by either blocking fat absorption by suppresing appetiteTo be effective, drug therapy should be administered in conjunction with lifestyle modifications.
Surgery:
Surgery is only indicated for weight control when all other medical/dietary treatment has failed. Furthermore, the 1991 NIH consensus recommends that all candidates considered for Bariatric Surgery meet the following criteria:
- BMI > 40
- BMI >35 with co-morbidities
- Failed medical management
- No psychological contraindications
- Age of less than 60 years old
According to the Society of Bariatric Surgery, all surgical procedures aimed to reduce and control weight can be classified as:
1- Restrictive procedures (limit the amount of food intake)
2- Malabsorptive procedures (limiting fat absorption into the body)
A. Gastric Restrictive Procedure - Vertical Banded Gastroplasty
In this procedure, the upper part of the stomach is stapled vertically to create a small pouch while a ring of non-absorbable material is placed to restrict the passage of food to the rest of the stomach (see figure 1). Patients usually achieve 50% of excess weight loss during the first year. However, care must be taken not to consume sweets or liquids rich in calories as they can easily pass through the site of restriction (ring). The most frequent complications seen with this technique are staple line disruption with consequent discharge of gastric juice into the abdomen (leak) and severe obstruction at the ring level, which may require several surgical interventions to correct.
Figure 1. Vertical Banded Gastroplasty (Adapted from Ethicon.Inc. Reproduced with permission)
B. Malabsorptive Procedures - Biliopancreatic Diversion
In this procedure, ¾ of the stomach is removed, and the bowel is divided to divert all biliary and gastric juices from ingested food. The technique involves division of the small bowel very close to its junction to the large bowel or colon to be reconnected to the gastric pouch. A small communication between the pouch and the intestine is performed to create a restrictive mechanism (see figure 2). This operation results in one of the best weight loss outcomes (90% of excess weight loss at five years) as it provides the highest degree of malabsorption. Complications related to this procedure include severe diarrhea, abdominal bloating and protein malnutrition.
Figure 2. Biliopancreatic Diversion (Courtesy of Ethicon – Reproduced with permission)
C. Combined Restrictive and Malabsorptive Procedure - Gastric Bypass Roux-en-Y
This gastric bypass procedure is considered to be the gold standard by the American Society for Bariatric Surgery (ASBS) and the NIH, and it is the most frequently performed weight loss surgery in the United States and throughout the world. The procedure involves the division of the stomach to create a small gastric pouch of not more than 3 ounces in capacity. The rest of the stomach or the gastric remnant is left in the abdomen untouched. The small bowel is divided and the gastric transit is reconstituted by joining the divided small bowel or Roux-limb to the gastric pouch. The remaining small bowel is connected to the roux limb from entertaining a “Y” shape (roux-en Y) (see figure 3). This operation can be performed “open” through a standard midline incision in the abdomen or via the laparosocopic approach using a small video camera with small instruments that are inserted through small incisions made in the abdominal wall. The Roux-en-Y procedure is very effective with patients losing up to 75% of their excess weight in 15 years. Complications following gastric bypass include leaks at the connection between the gastric pouch and the divided small bowel, vein clots, strictures, malnutrition, anemia and dumping syndrome (fatty diarrhea). Studies have shown that obesity-related health problems such as hypercholesterolemia, type 2 diabetes, reflux disease, hypertension and sleep apnea are either cured or significantly improved following gastric bypass.
Figure 3. Gastric Bypass Roux-en-Y (Adapted from Ethicon.Inc – Reproduced with permission)
1- Gastric Remnant; 2-Roux Limb; 3- Gastric Pouch; 4 – Roux –en –Y.
Laparoscopic Adjustable Gastric Banding (Lap-BAND® System©)
This procedure involves the placement of a band around the upper part of the stomach creating a restriction to food intake. Most patients feel enough pressure in the pouch, which is translated into a feeling of fullness and loss of appetite. The band can be easily adjusted to increase or decrease the restrictive mechanism (see figure 4). Although the weight loss achieved with the Lap-BAND® System is less than that achieved with gastric bypass, this option is very appealing to patients because of the simpler surgical technique and its reversibility. As in any surgical procedure for morbid obesity, the Lap-BAND® System also carries its own risks and complications including stomach perforation with subsequent leakage, slippage or erosion of the band, nausea, vomiting and obstruction.
Figure 4. Laparoscopic Adjustable Gastric Banding
(Adapted from Ethicon.Inc – Reproduced with permission)1- gastric pouch; 2-esophagus; 3 -stomach
Click Here for more information on the Lap-BAND® System
Risks and Complications of Bariatric Surgery
Bariatric surgery is not cosmetic surgery and should not be considered until other options have proved to be ineffective. As in any surgical procedure, patients undergoing any of the above-mentioned techniques are at risk for bleeding, infection or suffering an injury to other organs (liver, spleen, large bowel etc). In addition, patients specifically undergoing any type of obesity surgery may suffer other types of complications such as leaks at the connection sites, blood clotting, strictures, bowel obstruction, malnutrition, anemia and even death. Choosing surgery for weight control should be the result of an extensive evaluation from the medical/surgical team as well as a good understanding by the patient. Bariatric surgery candidates must have realistic goals regarding outcomes and fully understand the level of commitment required. If the laparoscopic approach is chosen, the patient should be aware that converting the procedure to an open technique could be due to several factors and is not necessarily an indication that an intraoperative complication was encountered. Many times the decision to “convert-to-open” is made to avoid complications. Overall, Bariatric surgery is safe and effective, achieving significant weight loss post-operatively and improving the quality of life. Strict postoperative follow-ups are needed to monitor the patient’s nutritional status.
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