Are there different levels of obesity?

I have hered that there are different levels of obesity something like level III. How many levels are there and how it is defined that level?

Here there is overweight, obese, morbidly obese, super morbidly obese.  I think they are defined by BMI. 

Found this website, added the link for you to read all of it.




There are different levels of obesity which along with being overweight are measured using a BMI (Body Mass Index) calculator.  This tool performs a series of calculations based upon a person’s height, sex and weight.  For example, weight in kilograms x height in metres.  This enables your doctor or healthcare professional to assess whether you fall into one of the following categories:

• Below 18.5 - classed as underweight
• 18.5 to 24.9 - classed as a healthy weight (normal)
• 25 to 29.9 - classed as overweight
• 30 to 34.9 - classed as obese
• 35 to 45 - classed as severely obese
• 45 to 50 - classed as morbidly obese
• 50 to 60 - classed as super obese
• 60 upwards - classed as super-super obese

It is important to remember that BMI is a guide only.  These definitions apply to many people but are not suitable for the very young, very old and sportspeople.


http://www.medic8.com/healthguide/articles/obesity.html

I've seen the levels used sometimes in medical articles. I've never seen a definition anywhere. I am going to assume they track pretty closely to Obese, Morbid Obese and Super Morbid Obese but I'd like to know for sure.