The reasons for obesity are multiple and complex. Despite conventional wisdom, it is not simply a result of overeating. Research has shown that in many cases a significant, underlying cause of morbid obesity is genetic. Studies have demonstrated that once the problem is established, efforts such as dieting and exercise programs have a limited ability to provide effective long-term relief.
Science continues to search for answers. 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 very important to understand that all current medical interventions, including weight loss surgery, should not be considered medical cures. They are meant to be tools to reduce the effects of excessive weight and alleviate the serious physical, emotional and social consequences of the disease.
The underlying causes of severe obesity are multifactorial and not completely understood. There are many factors that contribute to the development of obesity including genetic, hereditary, environmental, metabolic and eating disorders. There are also certain medical conditions and medications that may result in obesity such as intake of steroids and hypothyroidism.
Numerous scientific studies have established that your genes play an important role in your 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.
We probably have a number of genes directly related to weight. Just as some genes determine eye color or height, others affect our appetite, our ability to feel full or satisfied, our metabolism, our fat-storing ability, and even our natural activity levels.
We used to think of weight gain or loss as only a function of calories ingested and then burned. If you take in more calories than you burn, this leads to weight gain.
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, once you return to prior caloric intake or revert back to your initial behaviors.
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 all magnify hereditary factors such as metabolism and efficient fat storage. A total change in environment is not an option for most, therefore cultural dietary and exercise behaviors must be learned to achieve long term weight loss.
Eating Disorders & Medical Conditions
Weight loss surgery is not a cure for eating disorders. There are medical conditions, such as hypothyroidism, that can also cause weight gain.