Understanding Obesity
Simply put, obesity is a complex disease
characterized by excessive body fat. The physiologic biochemical
and genetic evidence is overwhelming that clinically severe obesity
is not a simple disorder of will power, but a complex disease. While
the biological basis is not fully understood, contributing causes
include heredity, environmental, cultural, socioeconomic and psychological
factors. Women are eight times more susceptible to clinically severe
obesity than men. We know that "insulin resistance," the
manner in which insulin is produced in the pancreas and used at
the cell level, is another genetic factor contributing to the disease.
Adipose tissue deposition and energy efficiency also seem to be
genetically based.
Genetically predisposed patients experience "over-adjustment"
of metabolic rate in response to strenuous dietary efforts.
Non-genetic factors include total energy (food calories) intake,
total internal and external energy used, and relative proportions
of proteins, fats and carbohydrates in one's diet. Frequency and
duration of physical activity patterns of leisure activity (i.e.
sedentary versus active) and the amount of lean muscle mass being
carried are among the non-genetic factors that determine one's predisposition
to clinically severe obesity.
New research has begun to pinpoint precise genetic differences
at the chromosomal level which lead to severe obesity.
Published scientific reports document that non-operative methods
alone have not been effective in achieving a medically significant,
long-term weight loss in severely obese adults. To add insult to
injury, diets do not work, and in fact usually compound the "yo-yo"
effect. In 95 percent of cases, any weight lost through these numerous
programs is regained within one to five years.
The 1991 National Institutes of Health (NIH) Consensus Development
Conference Statement on the surgical treatment of obesity says those
who have had little success with diets or other non-surgical treatments
may be considered for surgical treatment. Surgery is not necessary
to cure obesity, but is sometimes medically necessary for clinically
severe obesity because it offers virtually the only effective long-term
method of weight control.
At what stage does obesity become clinically severe or morbid obesity?
Several methods are currently in use to classify clinically severe
obesity. The two most common are excess weight based on "Ideal
Calculated Weight" and "Body Mass Index" (BMI).
Determining ideal calculated weight is slightly different for men
and women. For both, excess weight is the amount of weight greater
than the ideal calculated weight. The calculation for Ideal Calculated
Weight is approximate:
- For Men: 106 lbs. plus six lbs. for each inch in height over
five feet
- For Women: 100 lbs. plus five lbs. for each inch in height over
five feet
Using NIH guidelines, roughly 100 pounds greater than the ideal
Calculated Weight constitutes clinically severe obesity; and indicates
that surgical treatment may be considered. In cases where co-morbid
conditions such as diabetes, hypertension, respiratory ailments
and bone and/or joint disease are severe, an excess weight even
lower than 100 pounds may be considered for surgical treatment.
Successful Treatment Expectations
In general, successful treatment of clinically severe obesity requires
a loss of a major portion of excess weight, improvement or cure
of co-morbid conditions, and lifelong commitment. Success with respect
to this operation is defined as achieving a weight within 40 pounds
(or less) of ideal body weight. This usually takes place between
12 and 18 months after surgery in patients who follow the recommended
diet and exercise programs. In the experience of centers across
the country, over 80 percent of patients achieve this goal. Excellent
weight loss is a reduction of 50 to 75 percent of excess weight.
1991 NIH Obesity Study
Body Image & Psychological Aspects of Morbid Obesity