Extreme obesity

What are the criteria for someone crossing the line from being a bbw or bhm to a ssbbw or ssbhm?

There is already a thread about this:
fantasyfeeder.com/forum/posts

Personally I've always looked at it as the point your waist size is larger than your height.

I say waist specifically because I've known a few ladies with weird distribution that I wouldn't call particularly fat but that could break the hips to height ratio.