Causes of Obesity

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 a person is obese, efforts such as dieting and exercising by themselves have limited the ability to provide effective long-term relief. We are learning that many people get obese by skipping meals or not eating. Other individuals find that they respond to stress by eating starchy or sugary foods. Still others find that they crave certain foods and there is no “willpower” strong enough to counter this urge. Medications and meal replacement systems have shown promise to correct these genetic propensities.

Science continues to search for answers and effective medical treatments for obesity. 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 treatments for obesity, including weight-loss surgery, should not be considered cures. Rather they are attempts to reduce the effects of excessive weight and alleviate the serious physical, emotional and social consequences of the disease. Both medical and surgical interventions will require a commitment to a lifetime of maintaining weight-loss and healthy living.

Contributing Factors

While the underlying causes of morbid obesity are not known, there are many factors that contribute to the development of obesity. These include stress, certain medications, conditions such as hypothyroidism, fatigue syndromes, and certainly, our dietary environment.

Genetic Factors

Obesity research and 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.

Obesity research further suggests that 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. Your Loma Linda University Metabolic Surgery team is active in this research.

Environmental Factors

Environmental and genetic factors of obesity are obviously closely intertwined. If you have a genetic predisposition toward obesity, then the modern American lifestyle and environment will make controlling weight more difficult.

Fast food, long days sitting at a desk and suburban neighborhoods that require cars all magnify hereditary factors. The very foods that make us fat are the same foods that our food industry makes the greatest profit on. For these reasons, it is essential to accommodate these realities through systems that change our appetites, cause us to remember to eat and make us “conscious eaters”. Bariatric surgery can help by making all this happen


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. This “set point” can be altered with medication or eating more frequently, resulting in weight loss. If the system that helped you lose weight is laid aside, then it is quite clear that you will regain your weight. This is similar to taking off your prescription glasses which you rely on to see. If you take them off, then you cannot see clearly. Weight loss works the same exact way. Even with bariatric surgery, you can override the system and regain the weight.

Eating Disorders & Medical Conditions

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.