July 23, 2007 Hello! Even if they don't quite understand it, most people have heard the term, "BMI."
"Body Mass Index (BMI) is a number calculated from a
person’s weight and height. BMI is a reliable indicator of
body fatness for people. BMI does not measure body fat
directly, but research has shown that BMI correlates to
direct measures of body fat ... Additionally, BMI is an
inexpensive and easy-to-perform method of screening for
weight categories that may lead to health problems." For years, health care professionals have stressed the importance of having a "healthy" BMI for both adults and children, but knowing a person's BMI is not enough to determine if that person is healthy -- or even if that person has too much body fat.
"BMI is used as a screening tool to identify possible
weight problems for children. CDC and the American Academy
of Pediatrics (AAP) recommend the use of BMI to screen for
overweight in children beginning at 2 years old. For
children, BMI is used to screen for overweight, at risk of
overweight, or underweight. However, BMI is not a
diagnostic tool. For example, a child may have a high BMI
for age and sex, but to determine if excess fat is a
problem, a health care provider would need to perform
further assessments. These assessments might include
skinfold thickness measurements, evaluations of diet,
physical activity, family history, and other appropriate
health screenings." To complicate things further, what is considered a "healthy" BMI varies by age for children and teens.
"Figuring out the body mass index is a little more
complicated for teens than it is for adults (that puberty
thing again). BMI charts for teens use percentile lines to
help individuals compare their BMIs with those of a very
large group of people the same age and gender. There are
different BMI charts for guys and girls under the age of
20. ..."
The following site provides access to both an adult BMI
calculator and a child and teen BMI calculator: While an online resource can help a person figure out his or her BMI -- and even plot that score to show percentile -- it can be confusing when trying to figure out what all that means.
"Although you can calculate BMI on your own, it's a good
idea to ask your doctor, school nurse, or fitness counselor
to help you figure out what it means. That's because a
doctor can do more than just use BMI to assess a person's
current weight. He or she can take into account where a
girl or guy is during puberty and use BMI results from past
years to track whether that person may be at risk for
becoming overweight. Spotting this risk early on can be
helpful because the person can then make changes in diet
and exercise to help avert developing a weight problem.
People don't like looking overweight, but weight problems
be more serious than someone's appearance. People who are
overweight as teens increase their risk of developing
health problems, such as diabetes and high blood pressure.
Being overweight as a teen also makes a person more likely
to be overweight as an adult. And adults who are overweight
may develop other serious health conditions, such as heart
disease." Hearing that there are health concerns associated with being overweight is nothing new for most people, but there is more to it than just being a "healthy" weight.
"Some doctors now believe the internal fat surrounding
vital organs like the heart, liver or pancreas -- invisible
to the naked eye -- could be as dangerous as the more
obvious external fat that bulges underneath the skin.
'Being thin doesn't automatically mean you're not fat,'
said Dr. Jimmy Bell, a professor of molecular imaging at
Imperial College, London. ... According to the data, people
who maintain their weight through diet rather than exercise
are likely to have major deposits of internal fat, even if
they are otherwise slim. 'The whole concept of being fat
needs to be redefined,' said Bell... Without a clear
warning signal like a rounder middle, doctors worry that
thin people may be lulled into falsely assuming that
because they're not overweight, they're healthy. 'Just
because someone is lean doesn't make them immune to
diabetes or other risk factors for heart disease,' said Dr.
Louis Teichholz ... Even people with normal Body Mass Index
scores -- a standard obesity measure that divides your
weight by the square of your height -- can have surprising
levels of fat deposits inside." A high BMI can serve as a warning to some, while a normal, or even low, BMI can provide a false sense of security to others. Being thin does not necessarily mean being healthy.
"In books, in medical journals and at public health
conferences, scientists have been dueling over the relative
importance of fatness vs. fitness, and whether there is any
common ground between the two camps. A small but vocal
cadre of researchers has been challenging conventional
wisdom, arguing that not only is it possible to be both fat
and fit, but fitness is actually more important for health.
'All too often, medical professionals say it's the obesity
we have to cure. That's the be-all and end-all. It's not...
The impression is that everyone who is overweight faces an
elevated risk for mortality. That's simply not true.' Other
experts, however, maintain that while there may be
exceptions, the evidence is clear for most people: Being
overweight significantly increases the risk of a host of
debilitating and often deadly health problems, including
heart attacks, strokes, cancer and diabetes." How much weight a person has -- or doesn't have -- may be fairly easy to see and/ or measure. However, a person's weight and/ or BMI score alone can not determine how healthy that person is. Recently, doctors have found a way to measure the hidden "internal fat surrounding vital organs like the heart, liver or pancreas" that can cause health problems in those who appear healthy from the outside.
"Measuring blood levels of a chemical transporter for
vitamin A [called retinol-binding protein (RBP4)] may be
useful in estimating a person's "intraabdominal fat," a
type of fat inside the abdomen that it not visible, but
still adversely affects health, new research shows. ...
Increased blood levels of RBP4 'appear to be a very good
indicator of insulin resistance and increased
intraabdominal fat, two risk factors that are notoriously
difficult to assess... since they require complicated
biochemical testing and advanced imaging techniques' ... As
noted, increased levels of the protein were seen in
subjects with high amounts of intraabdominal fat and in
those with insulin resistance. In fact, RBP4 was a better
predictor of intraabdominal fat and insulin resistance than
several other blood tests that were evaluated. Monitoring
RBP4 levels 'may one day provide a simple tool for
assessing these risks and tailoring treatments in
patients," Graham concludes. In addition, the current RBP4
findings may help explain why high levels of intraabdominal
fat increase the risk of heart attack and stroke.' Thin people who don't exercise may not be healthy. Overweight people who do exercise may be more fit and have fewer health problems than those who are thin yet don't exercise. Does this mean that weight doesn't matter?
"Willett is also concerned that turning the focus away from
weight will keep people from being vigilant about
preventing weight gain in the first place, which is the
most effective strategy. 'One of the big problems is by the
time people become overweight or obese it's very hard for
them to become active. They've developed arthritis or other
problems that makes it hard, which is why we have to pay
attention to weight early on.'" Thin people who also exercised and were "fit" had the fewest risk factors for heart disease and stroke. Overweight people who did not exercise had the most risk factors. Weight is still an issue, but it is not the only issue.
Questions of the Week: Please email me with any ideas or suggestions. I look forward to reading what you have to say. Cindy |
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