Although exact mechanisms of this disease are still being discovered, there are several factors involved including genetics, metabolic, neuroendocrine and, above all, environmental factors.
The reasons for obesity are multiple and complex. Despite conventional wisdom, it is not simply a result of overeating. Studies have demonstrated that once the problem is established, efforts such as dieting and exercise have a limited ability to provide effective long-term relief.
Science continues to search for answers. But until the disease is better understood, the control of excess weight is something patients must work at for their entire lives. That is why it is important to understand that all current medical interventions, including weight-loss surgery, should not be considered medical cures. Rather they are attempts to reduce the effects of excessive weight and alleviate the serious physical, emotional and social consequences of the disease.
Some of the hypotheses about obesity:
There are many factors that contribute to the development of obesity including genetic, hereditary, environmental, metabolic and eating disorders, but the underlying causes of severe obesity are not known. There are also certain medical conditions that may result in obesity like intake of steroids and hypothyroidism.
Numerous scientific studies have established that genes play an important role in the tendency to gain excess weight.
- The body weight of adopted children shows no correlation with the body weight of their adoptive parents, who feed them and teach them how to eat. Their weight does have an 80 percent correlation with their genetic parents, whom they have never met.
- Identical twins, with the same genes, show a much higher similarity of body weights than do fraternal twins, who have different genes.
- Certain groups of people, such as the Pima Indian tribe in Arizona, have a very high incidence of severe obesity. They also have significantly higher rates of diabetes and heart disease than other ethnic groups.
- A number of genes directly relate to weight. Just as some genes determine eye color or height, others affect the appetite, the ability to feel full or satisfied, metabolism, fat-storing ability, and even natural activity levels.
The Pima Paradox
The Pima Indians are known in scientific circles as one of the heaviest groups of people in the world. National Institutes of Health researchers have been studying them for more than 35 years. Some adults weigh more than 500 pounds, and many obese teenagers are suffering from diabetes, the disease most frequently associated with obesity.
But here's a really interesting fact--a group of Pima Indians living in Sierra Madre, Mexico, do not have a problem with obesity and its related diseases. Why not?
The leading theory states that after many generations of living in the desert, often confronting famine, the most successful Pima were those with genes that helped them store as much fat as possible during times when food was available. Now those fat-storing genes work against them.
Though both populations consume a similar number of calories each day, the Mexican Pima still live much like their ancestors did. They put in 23 hours of physical labor each week and eat a traditional diet that's very low in fat. The Arizona Pima live like most other modern Americans, eating a diet consisting of around 40 percent fat and engaging in physical activity for only two hours a week.
The Pima apparently have a genetic predisposition to gain weight. And the environment in which they live--the environment in which most of us live--makes it nearly impossible for the Arizona Pima to maintain a normal, healthy body weight.
Environmental and genetic factors are obviously closely intertwined. If you have a genetic predisposition toward obesity, then the modern American lifestyle and environment may make controlling weight more difficult.
Fast food, long days sitting at a desk, and suburban neighborhoods that require cars all magnify hereditary factors such as metabolism and efficient fat storage. For those suffering from morbid obesity, anything less than a total change in environment usually results in failure to reach and maintain a healthy body weight.
We used to think of weight gain or loss as only a function of calories ingested and then burned. Take in more calories than you burn, gain weight; burn more calories than you ingest, lose weight. But now we know the equation isn't that simple.
Obesity researchers now talk about a theory called the "set point," a sort of thermostat in the brain that makes people resistant to either weight gain or loss. If you try to override the set point by drastically cutting your calorie intake, your brain responds by lowering metabolism and slowing activity. You then gain back any weight you lost.
Eating Disorders and Medical Conditions
It’s important to understand that weight-loss surgery is not a cure for eating disorders. And there are medical conditions, such as hypothyroidism, that can also cause weight gain. That's why it's important that you work with your doctor to make sure you do not have a condition that should be treated with medication and counseling instead of surgery.
Health Threats of Morbid Obesity
Morbid obesity brings with it an increased risk for a shorter life expectancy. For individuals whose weight exceeds twice their ideal body weight (that's about two to six percent of the U.S. population), the risk of an early death is doubled compared to non-obese individuals.
The risk of death from diabetes or heart attack is five to seven times greater. Even beyond the issue of obesity-related health conditions, weight gain alone can lead to a condition known as "end-stage" obesity where, for the most part, no treatment options are available. Yet an early death is not the only potential consequence. Social, psychological and economic effects of morbid obesity, however unfair, are real and can be especially devastating.
What Do the Medical Experts Say?
Experts with the National Institutes of Health have concluded that severe obesity, "reduced life expectancy and significant psychosocial and economic problems are experienced by severely obese people." National Institute of Health has also concluded that gastric bypass is an effective treatment for Type II Diabetes in the insulin dependent, diabetic, bariatric patient.
"Limited success has been achieved with a variety of non-surgical approaches including medically supervised dieting. Diet alone cannot be considered a reasonable option for permanent weight-loss. Drug therapy for clinically severe obesity has been disappointing." The panel endorsed two surgical treatments for obesity: gastric bypass and gastric banding, noting that "significant weight-loss usually occurs and a number of associated disorders (such as diabetes and hypertension, etc.) often improve."
In addition, several large clinical studies have proven that diet or drugs alone cannot achieve a sustainable weight-loss necessary to alleviate the associated medical problems of obesity. Although not without risks, the gastric bypass procedure is still considered the gold standard surgical procedure for the surgical cure of severe obesity. Several studies have shown that this technically challenging operation is relatively safe, with a low risk of long-term nutritional side effects when compared with other operations, including the vertical banded gastroplasty and biliopancreatic diversion.