Obesity, What’s
“Big” Deal? Part III ---------------------------------------------------------- This article has been provided by Dr. M. Montgomery at www.healthyunderstanding.com Dr. Montgomery is a practicing Chiropractor in Saskatoon, Saskatchewan. -------------------------------------------------------------------- Previously we have discussed obesity epidemic, Surgeon General’s warning, associated risks of this condition, definition of obesity and overweight, as well as some of excuses and lifestyle factors associated with obesity.In this issue we will discuss some methods of fat calculation, and cut off levels associated with increased risk.
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Methods of Fat Calculation
There are numerous ways in which to calculate approximate fat content of an individual’s body. Some of more commonly known methods are: BMI (Body Mass Index), DEXA (dual energy x-ray absorptiometry), bioelectrical impedance analysis, skin caliper pinch tests, and underwater weighing. The most direct measures of body fat, such as underwater weighing or DEXA scanning, are impractical for use. Indirect estimates of body fat are more practical. (1)
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Body Mass Index
One of most commonly used methods is BMI due its ease of use. The calculation for this is BMI = weight (in Kg)/height (m)˛. The values for different ages show relative health risks.
Although BMI has been used to evaluate overweight and obesity in adults for many years, it has recently been recommended for screening of children and adolescents. With this change you can use it from age of 2 years through to adulthood. However, BMI is used differently to define overweight in children and adolescents than it is in adults. (2)
Overweight in children and adolescents is defined as a BMI-for-age at or above 95th percentile on CDC growth charts. The risk of overweight for ages 2-20 years is defined as a BMI-for-age between 85th and 95th percentiles. (2)
a BMI of 27.3 or more for women and a BMI of 27.8 or more for men.
The World Health Organization assigns an increasing risk for developing other conditions including hypertension, type 2 diabetes mellitus, and cardiovascular disease for people with higher BMI’s as compared to persons of normal weight. Normal is defined as having a BMI between 18.5 and 25 for those of European descent and for those of Asian descent, a BMI of 18.5 to 23 is normal.(1)
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Fat Distribution
In addition to an increase in total body fat, a proportionally greater amount of fat in abdomen or trunk, compared with fat in lower extremities or hips, has been associated with increased risk for diabetes, hypertension, and heart disease for both men and women. For people of Asian descent, abdominal (central) obesity is recognized to be a better indicator of future difficulties than BMI. (1)
This abdominal obesity is commonly reported as a waist-to-hip ratio, but it is most easily quantified by a single measurement done at approximately belly button. Men are considered to have an increased relative risk for coronary artery disease, diabetes, and hypertension if they have a waist circumference of 40 inches (102 cm) or more; whereas women are at increased risk if their waist circumference is 35 inches (88 cm) or more. (1).
