Can I tell my sister her online snaps are too racy?

And if you feel like it, you can get involved or just enjoy the voyeuristic experience.’

That last bit bothers me, as it does you. Fat fetishism may do no harm (although it depends what pervy ‘voyeurs’ want and do, and where the pictures go). But it is certainly unwise for anybody in a responsible job to post highly sexualised images on Facebook, even in a private group. Pictures are so easily copied and you can have no idea how they are distributed.

What’s more, many of the ‘likes’ encouraging more outrageous pictures are likely to come from nasty, sleazy men, posing as the fat sisterhood. If that was my sister, I too would feel worried.

After so many years, she must feel so excited at looking (she thinks) sexy (and being praised by strangers) that she never stops to think of consequences.

It disturbs me that so many women have no need to be objectified by men (as we’ve been for centuries) because they do the job so well themselves. The vile, multibillion dollar pornography trade has corrupted too many people.

Nowadays girls as young as ten think it fine to create sexualised avatars of themselves and their friends, while intelligent, professional women develop that vacant porn star pout. Kim Kardashian’s epic rear has inspired a million provocatively posing rumps, many of which are amply displayed on that commercial website for any-old-body to see.

Even though you love your sister and have her interests at heart, you do run the risk (if you speak up) of a quarrel which could never be healed. She might say — if you are so ‘disappointed’ and ‘embarrassed’ and see her as ‘cheapened’ — how that speaks volumes about you, not her. If you hurt her feelings, she’s likely to lash out with verbal defiance and tell you to mind your own business. Then (I bet) cry in private.

So tread carefully. You could mention somebody you know saw her pictures and was so shocked and puzzled they asked you what she is doing. You would need to be cool. Or you could see this as just a phase and hope nobody she works for (or with) spots her.

Perhaps she is so thrilled by her new, confident selfhood that she is playing a game which she will tire of in the end.