The biological basis for severe obesity remains unknown.

Recent investigations, however, have identified multiple abnormal proteins, present in the brain and peripheral blood of morbidly obese patients. These proteins, many of which are known to alter appetite, satiety, and energy conservation, are associated with genetic abnormalities as well.

Obesity is not caused by one protein, one gene, or one lifestyle habit. Contributing causes of obesity are numerous. It is likely that obesity is the result of a combination of factors, including genetic, environmental, cultural, socioeconomic, and psychological components.

Whatever the exact causes may be, it is certain that morbid obesity is truly a complex disease -- not just a disorder of willpower.

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