Obesity is a disease, not a personality disorder, with both genetic and environmental causes leading to the accumulation of excess fat, which can be, and often is, detrimental to health. The amount that one's health is affected by obesity correlates well with how obese they are and how long they've been obese. In order to assess health risk, obesity is defined by medical and scientific communities, by a method which accounts for the relative contributions of height and weight, by what's called the Body Mass Index or "BMI." BMI is expressed as kg/m2 , and can be calculated by:

Multiply your weight in pounds by 705
Divide that number by your height in inches
Divide that number by your height in inches

Calculate your BMI

Obesity categories, according to BMI, as classified by the World Health Organization (WHO) and National Institutes of Health (NIH)are as follows:

BMI		Obesity Category
Below 19		Underweight
20 â´¼/td>		Normal
25 â¹¼/td>		Overweight
30 ã´¼/td>		Obese
35 ã¹¼/td>		Severely Obese
40 ä¹¼/td>		Morbidly Obese
50 +		Super Obese

Ideal Body Weight (IBW), is the combination of height and weight at which is associated the best health. It is derived from Height-Weight tables and the simplest formula for it is:

Hamwi formula:
Females, 100 lbs for 1st 5 ft, +/- 5 lbs for every inch above or below
Males, 106 lbs for the 1st 5 ft, +/- 6 lbs for every inch above or below

Excess Body Weight = Actual Body Weight 餥al Body Weight

Calculate your IBW

Morbid Obesity is defined as having a BMI over 40. This equates to being about 110 lbs over your IBW. This is the category of obesity with which is associated the most health risk.