How is obesity defined and measured?

'''Obesity''' is defined as having an excessive accummulation of body fat. Obesity is being at a body weight that is considered unhealthy. The terms "overweight" and "obesity" can sometimes be mistaken for the same meaning. However, '''overweight''' is defined as a body weight in excess of a recommended range for good health. '''BMI''', or body mass index, is a method of classifying overweight and obesity.