Body Fat BMI

What exactly is BMI (Body Mass Index)

BMI is an approximate measure of body fat based on weight and height proportion. An accurate Body fat evaluation also must take into account circumference of the waist. Keep in mind that it is for guidelines only and offers an approximation or snapshot of body fat – it can over estimate Body fat in those with a lot of lean muscle mass – but of course if you are in that kind of shape – you probably are not here reading pages on weight loss.

However in can underestimate body fat to on people that are lighter in weight due to significant loss of muscle mass, like the elderly. To calculate BMI take your weight in pounds x 703 and divide that by your height in inches squared. Compare the resulting number to the chart below.

Medical professionals agree anyone with a BMI of 30 or above really needs to start a weight loss program. Those with a BMI in the 25-29 range that exhibit one or more of the other risk factors for obesity also need to slim down. Losing only 10% of your body fat can significantly reduce your risk for obesity related conditions, and improve you overall health, body image and self-esteem.

Is BMI Important?

While the formula previously called the Quetelet Index for BMI dates to the 19th century, the new term "body mass index" for the ratio and its popularity date to a paper published in the July edition of 1972 in the Journal of Chronic Diseases by Ancel Keys, which found the BMI to be the best proxy for body fat percentage among ratios of weight and height; the interest in measuring body fat being due to obesity becoming a discernible issue in prosperous Western societies. BMI was explicitly cited by Keys as being appropriate for population studies, and inappropriate for individual diagnosis. Nevertheless, due to its simplicity, it came to be widely used for individual diagnosis, despite its inappropriateness.

In short, if you have a lot of muscles then the BMI will tell you nothing. BMI does not measure fat. It is nothing but a ratio of weight to height. If you BMI is high and you don't have a lot of muscle then you shuld lose weight.

Because the BMI formula depends only upon weight and height, its assumptions about the distribution between lean mass and adipose tissue are not always exact. BMI sometimes overestimates adiposity on those with more lean body mass (e.g., athletes) while greatly under-estimating excess adiposity on those with less lean body mass. A study in June, 2008 by Romero-Corral et al. examined 13,601 subjects from the United States' Third National Health and Nutrition Examination Survey (NHANES III) and found that BMI-defined obesity was present in 21% of men and 31% of women. Using body fat percentages (BF%), however, BF%-defined obesity was found in 50% of men and 62% of women. While BMI-defined obesity showed high specificity (95% of men and 99% of women presenting BMI-defined obesity also presented BF%-defined obesity), BMI showed poor sensitivity (BMI only identified 36% of the men and 49% of the women who presented BF%-defined obesity).