Overweight?

Okay, good people of blog land. Can someone tell me when exactly, size 10 became to symbolise being over a healthy weight?!
It appears to have annoyed the Duchess of York.
Are we so obsessed with all our models and actresses being a size 0 (or size 4), that we've completely lost focus on what the rest of the world's female population look like?! Looking at the photo of Princess Beatrice with her mother, she appears to be a healthy, curvacious young woman. Certainly not overweight!
As for the size. Assuming she's a 10 - I'm a size 14. By the logic of whichever creep is calling Beatrice overweight, I must be pretty close to obesity!
And, I know I don't need to lose weight. If I lost any more weight I'd just be a skeleton with a couple of breasts. Don't we all know that the Victoria Beckham look is unappealing!
Who sets the standards for what is, and isn't, a healthy weight?! Because, it seems that far too much emphasis is being placed on a vague idea of overweight, and not enough on the unhealthily skinny models we see in our newspapers and on the catwalks. What kind of message is this sending to young girls and boys?! That it's okay to be perilously skinny, just don't be any bigger than a size 12!