Many Americans are at increased health risk because they are obese. The U.S.
Surgeon General, in a 1988 report on nutrition and health, estimated that
one-fourth of adult Americans are overweight. Obesity is a known risk factor for
chronic diseases including heart disease, diabetes, high blood pressure, stroke,
and some forms of cancer.
How
Is Obesity Measured?
Everyone needs a certain amount of body fat for stored energy, heat
insulation, shock absorption, and other functions. As a rule, women have more
fat than men. Doctors generally agree that men with more than 25 percent body
fat and women with more than 30 percent body fat are obese. Precisely measuring
a person’s body fat, however, is not easy. The most accurate method is to weigh
a person underwater – a procedure limited to laboratories with sophisticated
equipment.
Body
Fat
There are two simpler methods for estimating body fat, but they can yield
inaccurate results if done by an inexperienced person or if done on someone with
severe obesity. One is to measure skinfold thickness in several parts of the
body. The second involves sending a harmless amount of electric current through
a person’s body (bioelectric impedance analysis). Both methods are commonly used
in health clubs and in commercial weight-loss programs, but results should be
viewed skeptically.
Using
Tables
Because measuring a person’s body fat is tricky, doctors often rely on other
means to diagnose obesity. Two widely used measurements are weight-for-height
tables and body mass index. While both measurements have their limitations, they
are reliable indicators that someone may have a weight problem. They are easy to
calculate and require no special equipment.
Body
Mass Index (BMI)
Body mass index, or BMI, is a new term to most people. However, it is the
measurement of choice for many physicians and researchers studying obesity. BMI
uses a mathematical formula that takes into account both a person’s height and
weight. BMI equals a person’s weight in kilograms divided by height in meters
squared. (BMI = kg/m2). The table printed here has already done the math and
metric conversions. To use the table, find the appropriate height in the
left-hand column. Move across the row to the given weight. The number at the top
of the column is the BMI for that height and weight.
Body
Fat Distribution:
Doctors are concerned with not only how much fat a person has but where the
fat is on the body.
“Pears”
vs. “Apples”
Women typically collect fat in their hips and buttocks, giving their figures
a “pear” shape. Men, on the other hand, usually build up fat around their
bellies, giving them more of an “apple” shape. This is not a hard and fast rule,
though. Some men are pear-shaped and some women become apple-shaped, especially
after menopause.
Problems
With Ab Fat
People whose fat is concentrated mostly in the abdomen are more likely to
develop many of the health problems associated with obesity.
Waist-to-Hip
Ratio
Understanding Adult Obesity was originally published on blackdoctor.org
