Body Mass Index, BMI
The most convenient way to determine whether a person is at his/her ideal body weight is to use the Body Mass Index, BMI. BMI describes body weight relative to height. BMI values apply to both men and women and serve as a means for comparing adult persons in terms of underweight, normal weight, overweight and obesity.
BMI Classification (according to ACSM 2000, NIH 1998, WHO 1998):
For example, BMI of 25 to 29.9 indicates that the person is overweight and 30 or above that the person is obese.
BMI correlates with body fat except for people who have very large muscles e.g. weight-lifters. Thus, a weight-lifter may have BMI value that indicates obesity although the person only has large muscles and little fat tissue.
BMI can be calculated by using the following formulas, depending on the units preferred:
BMI = weight (kg) / height * height (m2) or BMI = 703 * weight (pound) / height * height (inch2)
ACSM's Guidelines for Exercise Testing and Prescription, 6th Ed. American College of Sports Medicine, 2000.
NIH (National Institutes of Health), National Heart, Lung and Blood Institute. Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults. 1998.
WHO. Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation on Obesity. Geneva: World Health Organisation, 1998.