Per the obese comments:
The medical field (and yes most of us know they aren't perfect either) set the definitions of obese as:
30% body fat or more in a male
35% body fat or more in a female
Sounds like a lot, but most people get there faster than a lot of us would guess.
I'll use myself as an example
Here is a goofy picture taken of me two months ago:
Goofy Dagta
I'm 5' 9", 185lb, and have a body fat of about 21%. So, I'm about halfway between 'ideal' bodyfat and 'obese' bodyfat. In other words, I'm medically overweight, probably in the area that the article referenced in the original post of this thread is talking about.
A lot of people that are considered 'chubby' are actually obese by medical standards.
Edit: typos