• Print this Page
  • Add Bookmark

Understanding Morbid Obesity

For individuals of average height, overweight can be categorized as morbid obesity starting at approximately 100 pounds over ideal weight. Scientists use a more exact measure called Body Mass Index (BMI). When BMI is greater than 35, patients are considered to be morbidly obese. The National Institutes of Health uses the term "Clinically Severe Obesity" in preference to "Morbid Obesity ".

Complications of the Morbid Obesity

As weight increases, the risks of obesity increase. The word "morbid" indicates that the obesity has interfered with normal body functions, leading to disease states and even to premature death. The younger a person is, the higher the risks of obesity. The death rate from severe obesity can exceed 12 to 20 times that of ideal weight individuals of the same age. This high death rate has numerous causes, including heart disease, high blood pressure, diabetes, blood clots in the legs, cancer of the colon and female organs, and sleep apnea. Autopsy studies have shown that sudden unexplained death occurs up to 40 times more frequently in the severely obese.

In addition to the physical complications, obese individuals struggle under a severe psychological and social burden. They may lose their self-confidence, isolate themselves, sink into a state of helplessness and no longer function within society.

Causes of the Morbid Obesity

Why morbid obesity develops is still not very well known, since the causes are numerous and they interact in a complex fashion. The simplified notion of obesity being due to over-eating is not helpful in either understanding the causes or in finding the remedy. Numerous factors have been identified that contribute to overweight. Obesity definitely runs in many families, and much evidence points to the importance of genetic factors. Important environmental factors are lack of nutritional information and motivation, lack of self-confidence, and the modern lifestyle centered around automobiles and fast food outlets.

Notwithstanding genetic or environmental factors, it also seems clear that once an individual exceeds a certain obesity level, he or she often cannot reverse it because of the complications and restrictions caused by the disease itself. A highly effective thermostat at work within the body acts to protect against the loss of weight. When caloric intake is severely reduced, as in dieting or fasting, a rapid biological adaptation occurs. The metabolism slows down in order to conserve energy and preserve the quantity of stored fat. Even worse, is what occurs when the diet is relaxed and the obese individual returns to a normal eating pattern. Weight gain occurs since the same amount of calories ingested now produced a larger surplus due to the more efficient metabolism. This is a barrier which the severely obese patient usually cannot overcome.

Well-established studies have demonstrated that 90 to 95 percent of obese individuals will regain all of the weight lost during dieting. The cause is not "failure of will power ", but rather the normal function of universal regulatory mechanisms, which are subconscious and impossible to change on a long term basis.

Treatment Approach

Certainly it is possible to stop smoking and to go without cigarettes on a permanent basis. It is not possible, however, to hold your breath for longer than several minutes. After a certain time, automatic subconscious drives take charge. Dieting is similar, since permanent fasting is not an option. Diet and exercise are good in the short term however over time dieting cannot be maintained and often the exercise component also cannot be sustained. Severe obesity develops gradually from the accumulation of a relatively small surplus in daily food intake above the energy burned up by exercise and normal metabolism.

A successful program to achieve permanent reduction in weight must therefore include a permanent change in either caloric intake or energy expenditure. Surgery can create a permanent change in the amount of calories absorbed, and at this time, surgery offers the only proven method for achieving long term sustained weight loss in the morbidly obese.


Picard Marceau, M.D. M.Sc., Phd., FRCS(C ), FACS
Simon Biron., M.D. M.Sc. FRCS(C ), FACS
Federic-Simon Hould, M.D. FRACS(C )
Martin Potvin, M.D. M.Sc., FRCS(C ), FACS
Roch-Andre Bourque, M.D., FRCS(C )

Gastrointestinal Surgery For Severe Obesity, NIH Consensus Development. Consensus Statement, 9(1), March 25-27, 1991, or American Journal of Clinical Nutrition, 55:615S,1992

Bouchard, C. "Genetic Factors in Obesity", Medical Clinic of North America, 73(1): 67-81, January 1989.

Bouchard, C. "Current Understanding of the Etiology of Obesity: Genetic and Non genetic Factors". American Journal of Clinical Nutrition, 53:1561S-5S, 1991.

Bouchard, C., A. Tremblay et J.-P. Despres. "The Response to Long-Terlm Overfeeding in Identical Twins":, New England Journal of Medecine, 322(21):1477-82, May 24, 1990.

Keesey, R.E. "Physiological Regulation of Body Weight and The Issue of Obesity", Medicine Clinic of North America, 73:15-27, Jan 1989.

Roncari, D.A.K.et A. ANGEL "the Fat Cell", Surgery for the Morbidly Obese Patient, Ed. Mervyn Dietel (Lea & Febiger): 3-18, 1989.

National Institute of Health Consensus Development Panel on the Health Implications of Obesity. "Health Complications of obesity", Annals International Medicine, 103: 1073-77, 1985.

Stunkard, A.J. et al "Psychological Aspects of Severe Obesity", American Journal of Clinical Nutrition, 55:524S-32S, 1992.

Back to News

Back To Top