BMI Classification

This is calculated using the Quetelet body mass index. The classification is taken from the World Health Organisation recommendations.

References Source: Adapted from WHO 1995, WHO 2000 and WHO 2004.

% body fat classification

The percentage fat is calculated using the Gallagher (2000) equation which is based on the age, sex, ethnicity and Quetelet body mass index.

The classification is taken from the same research which identified the percentage body fat that approximates to the WHO BMI thresholds.

The widely quoted thresholds for defining obesity from percentage body fat of 25% for males and 30% for females correlates poorly with conventional BMI definitions and is effetively a much lower threshold for diagnosing obesity.

Referencer
Gallagher D, Heymsfield SB, Heo M, Jebb SA, Murgatroyd PR, Sakamoto Y. Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. Am. J. Clin. Nutr. 2000 Sep 72(3):694-701.
American Council on Exercise
American Society for Bariatric Physicians