Recently I became a fat woman. Age, comfort eating, the stresses of being a head, too many meetings: all matters within my control but not under control. I've always had red hair so I'm used to the student who reaches for the first handy insult and finds "ginger" available. But now, when pupils feel invective is the only response, they choose "fat" or, more usually, "fat" and "ginger", and once (I think a quite engaging image) "fat, ginger cow".
But it has made me wonder. How does school feel to a fat child who has none of the resources of a head? I shadowed Jodie for a day because I wanted to know. Jodie is in Year 10, studious, conscientious, a prefect, lonely. Fat.
I watch as she struggles down the narrow aisle between desks. She carries lots of bags, which doesn't help, but when she stumbles and catches the shoulder of a boy, he says "fat cow" to her quite naturally and amicably - though he flushes slightly when he catches my glance. After Jodie takes her seat, I wonder if she suffers the discomfort I do - school chairs are not made for fat bottoms and the overhanging bits hurt after a while.
Being jostled while stuffing bags into corridor lockers is an endurance test for any pupil, but it's only Jodie who is abused as she does it. It's not nine o'clock and she's been called fat twice.
Her next two lessons pass without incident. Well, almost: I realise Jodie sits on her own despite seating plans which place her next to boys. I can't imagine the agony of that, when you are 15. But I also recognise the problem - in another, thinner life, haven't I minded the fat woman next to me on the train?
In English they are studying poetry about misfits. None is about fatness, but I wince for Jodie when the teacher's diagram includes, unchallenged, being fat as a cause of social isolation.
By the end of the day I'm exhausted with it. I've watched a PE lesson where the teacher - young, kind - has over-compensated at every turn for Jodie's lack of a partner. I went into the bleak changing rooms after the girls had gone and wondered how I'd feel - knew how I'd feel - if I had to change there in full public view. And finally, I went on to the school bus to check the students' seatbelts are fastened. As I watch her struggle to fasten hers, I think of the unintentional torture I've inflicted.
Do you know, though, what keeps me awake at night? At the end of that day I found that casual hatred of fatness contagious. I started to wonder why Jodie didn't do anything about being fat. And most importantly, she had exposed as a sham my belief that my school offers equality to its children. And, briefly, I hated her for it.
The writer is a headteacher in the east of England. To tell us what keeps you awake at night email firstname.lastname@example.org.