Alternatively, stop acting lazy and/or weird
Haha sorry I don't totally agree but it tickled me.
Workplaces can be pretty sly but to be fair I think everyone can be as bad as each other to an extent of course.
My advice to you, if you are being made to feel lazy, would be to hit back at the rotund memebers of staff and be quizical about the reasons they are of a "Plus Size" .
Is it from excessive excercise?
Or maybe a strict diet of healthy nutritional meals?
It could be because the only excercise they get is there bowels wobbling under the immense weight of their diet, their lungs having to expand or their chins chatting about other memebers of staff

No disrespect to overweight people (As long as your overweight following a medical or psychological issue other than green).
This may make me sound liek a tnuc but if you can dish it out and make someone feel bad, expect the same back.