The most commonly used measure of obesity, excessive body fat, is body mass index (BMI) which is calculated from the weight and height. BMI = weight (kg) / height (m)2. The assumption is that variation in weight for subjects with the same height is due to fat mass. BMI provides an easily measured continuous variable that allows comparisons of weight status and classification of normal, overweight and grades of obesity. While BMI gives some general information about body fatness, it does not measure fat and cannot accurately reflect fat mass or fat distribution in any person or group of people. The WHO (World Health Organization) has proposed classification of overweight and obesity based on BMI for adult men and women (2000). Use our online BMI calculator to measure.
The popular descriptions are also shown and reflect those generally used in the current bariatric literature. Other methods are used to measure fat mass and distribution. These vary from simple anthropometric measures such as waist circumference and skin-fold thickness to more sophisticated techniques using bioimpedance, hydrodensiometry, whole body composition, dual-energy x-ray absorptiometry, computed tomography and magnetic resonance imaging. All have their various advantages and disadvantages with respect to accuracy, practicality, availability and cost (Heymsfield et al, 1998). A focus of this thesis has been the use of simple clinical measures and their relation to obesity comorbidity. Waist circumference has been used as a simple clinical predictor of metabolic risk, identifying those at greater risk of coronary heart disease. A waist circumference of greater than 94 cm for men and 80 cm for women are associated with increased risk and measures of greater than 102 and 88 respectively represent substantially increased risk (Han et al, 1995; Kannel et al, 1991).