BMI underestimates body fat
Int J Obes 2012; 36:286-294
Body mass index (BMI) is a widely used measure to stratify people according to their total body weight; however, BMI does not discriminate between a person's total body fat or lean mass.
To estimate the degree of misclassificaton when using BMI, a cross-sectional study looked at cardiovascular and metabolic risk based on direct body fat percentage (as measured using air displacement plethysmography) in 6123 people who were classified according to their BMI as either lean (N=924), overweight (N=1637) or obese (N=3562).
A total of 29 per cent of participants classified as lean and 80 per cent of those classified as overweight, according to BMI, had body fat percentages within the obesity range. Concentrations of cardiometabolic risk factors were higher in BMI-classified lean and overweight participants who had body fat percentages in the obese range, and in BMI-classified obese participants, compared with lean volunteers and those with normal body fat amounts.
These results highlight the need for body composition measurements to be included in routine medical evaluation and practice for ascertaining those at risk of obesity.
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