You would think that PE teachers would have no excuses for being fat, but I'm a PE teacher and work with Elementary school kids.
Here's a typical scenario:
I'm having the kids run some laps around the track and to stay in shape, I decide that I will run around the track too. Well, 2 seconds into the activity, I have to stop MY running because some uncoordinated little monster fell and needs a band-aid. Then, some other punk decides to trip someone and I have to send him to the office.
If I want to work out, I have to do it at home on my own time NOT during work.
The other answerer was right too, many PE teachers have kids of their own, very busy lives with all of the stupid meetings and duties we have to do, illnesses of our own and in our families that need taking care of, staying in shape becomes very difficult.
Certainly the school doesn't care if the PE teacher or the other teachers is healthy or happy. They just want to know you are THERE and keeping the kids busy with what they want you to teach them.
I see your point and the irony of a fat person telling you to do something that they are not willing to do themselves, but ALL teachers do that.
The English teacher is asking you to write papers that she/he doesn't have to write. A great soccer coach doesn't need to be a great soccer player to be a great coach. As a matter of fact, some of the best coaches are fat, uncoordinated, slobs.
I teach PE and love to exercise.