Limitations of Using Body Mass Index (BMI) In Measuring Body Fat

Body mass index (BMI)) is a convenient and widely available measure of underweight, overweight and obesity. It is a proxy measure of excessive body fat. BMI does not distinguish between weight from fatty tissue and that from muscle tissue; nor does it indicate how an individual’s body mass is distributed. People who carry a disproportionate amount of weight around their abdomen are at a
higher risk of various health problems; waist circumference can therefore be a useful measure to gain additional insight, but it is measured less often and less easily than BMI (national obesity observatory, 2009).

BMI classifications were established based on risks of type 2 diabetes and cardiovascular disease, but populations and individuals vary in terms of how BMI relates to both body fat composition and the prevalence of disease (WHO, 2000). The limitations of the international BMI classifications are particularly evident among Asian populations. For example, in 2002 an expert group, convened by the World Health organization (WHO), found that the Asian populations considered have a higher percentage of body fat as well as higher incidence of diabetes and cardiovascular disease at lower BMIs than do Caucasians (controlling for age and sex). However, the experts also found differences in the appropriate BMI cut-off points among the Asian populations themselves.

The expert group decided to maintain the existing international standard classifications, but also recommended the development of an additional classification system for Asian populations that uses lower cut-offs and encouraged the use of country-specific cut-offs and the waist circumference measure (Nishida, 2004).