I think there is a very big difference in attitude between someone who actually thinks they are "fat/overweight" or are not very comfortable in their skin and people who just say it to get attention...
In general (and of course there are always the exceptions) I have found that people who are genuinely not comfortable in their skin or find themselves overweight etc don't tend to go around "advertising it" (i.e: "omg look how fat I am")
And I've also noticed that for the people going around saying they are fat when they are clearly not, most of them if you actually tell them they are fat will get upset and say they're not fat at all...
At least so far that's been my experience....
If you really think you're fat, you usually don't think there's a need to go around telling the world about it, because in your mind (whether it's true or not) everyone can tell, there's no need to advertize.
But of course there are always exceptions etc etc...
I have been there. When I was younger there was not a picking on me - although it's only now I realise that. I used to sit and break my heart at how huge I was and my friends would try to consol me - often we had to agree to disagree as they were my friends and, in mind, they were just lying to make me feel better. I always had a front so strangers / those not that close to me would never know and I wouldn't advertise it / tell the world - but if something upsets you you talk to your friends.
xx