Measuring Weightloss & Obesity
Weight Loss & Diet Details
BMI (body mass index)
is a simple and widely used method for estimating the proportion of body fat.
The BMI was developed by the statistician and anthropometrical scientist,
Belgian, Adolphe Quetelet. This is calculated by dividing the weight of the
subject (in kilograms) by the square of height (in meters), so it is expressed
in kg / mē.
The current definition in use provides the following values, agreed in 1997 and
published in 2000 BMI below 18.5 is below the normal weight.
BMI of 18.5-24.9 is normal weight.
BMI of 25,0-29,9 is overweight.
BMI of 30,0-39,9 obesity.
BMI of 40.0 or greater and severe
obesity (or morbid).
BMI of 35.0 or higher in the presence of
at least one other significant morbidity factor is also classified by some
people as morbid obesity.
In a clinical setting, physicians take into account race, ethnicity, lean mass
(muscle), age, sex and other factors which may infect the interpretation of
BMI.
BMI overestimates body fat in very muscular and can underestimate body fat in people who have lost body mass (many elderly people ).
Mild obesity as
defined by BMI is not a risk factor for cardiovascular and other health
problems and therefore can not be used as a unique clinical and epidemiological
predictor of cardiovascular diseases.
BMI does not take into account the differences between fat and lean tissue, nor
distinguish between different forms of adiposity, some of which may be
associated more closely with cardiovascular risk.
A better
understanding of the biology of adipose tissue has shown that visceral fat or
central obesity (male type obesity or apple type ) has a link with
cardiovascular disease, only to BMI
The absolute waist circumference (> 102 cm in men and> 88 cm in women) or
waist-hip ratio (> 0.9 for men and> 0.85 for women) are used as
measures of central obesity.
In a study of almost 15,000 subjects in the
National Health and Nutrition Examination Survey (NHANES) III, waist
circumference explained that BMI significantly improved risk factors for
obesity-related health when metabolic syndrome was taken as a measure.
Body fat
An alternative way to determine obesity is to measure the percentage of body
fat. Doctors and scientists generally agree that a man with more than 25% body
fat and a woman with more than 30% body fat are obese.
However, it is difficult to measure body fat accurately. The most accepted
method has been to weigh a person underwater, but this is a procedure limited
to laboratories with special equipment.