How to measure the body mass index
Obesity is defined as an excess of body fat in relation to lean body mass, both in terms of absolute quantity and distribution in specific parts of the body. The distribution of body fat can be carried out using different methods: the measurement of skin fold thickness, the relationship between waist circumference and hips, or using more sophisticated techniques as ultrasound, CT-scan and MRI. The Body Mass Index (BMI) is considered the most representative method of the presence of excess body fat.
BMI is calculated using the following formula:
BMI = Weight (kg) / squared height (in meters)
Weight classes are indicated by BMI:
< 18.5= underweight
18.5 to 24.9= normal weight
25 to 29.9= Overweight
> 30= Obese
There are of course gender differences: with an equal BMI women tend to have more body fat than men. Furthermore elderly people have more body fat than younger people. Athletes and especially weight lifters will be able to weigh more, because of well-developed muscle mass.