Here's a contemporary conundrum for you: how come celebs get thinner when they have kids, while the rest of us end up looking like blow-up versions of our former selves?

I saw a picture of the German model Claudia Schiffer in a tabloid newspaper the other day in which she was "showing off" her new post-natal look at an awards ceremony in Berlin.

Her new shape was described by the paper as "slimline", but then again it also described her former supermodel gauntness as "voluptuous", so what the heck does it know. To me, she looked like someone who had been living in solitary confinement for a year eating only cockroaches and the occasional moth.

She was very pale and was so thin that her teeny-tiny little dress had nothing to cling to; it just fell directly from her knobbly shoulders to her knobbly knees.

She was so thin that she had knobbles of bone sticking out at jaunty angles where no knobbles are normally seen.

Claudia attributed her elegant (for "elegant" read "emaciated" - they're quite close in the dictionary, so she probably got into a bit of a model muddle) new look to breastfeeding. I can only imagine she has been breastfeeding an entire rugby team 24 hours a day for the past 12 months.

Or does she really think that the tabloid-reading masses are gullible enough to believe a small child can devour an entire supermodel by itself? Sunday Sport readers perhaps, but not those of us who are capable of reading joined up writing and tying our own shoelaces.

But she's not the only celeb to all but disappear after popping out a celebaby. Just look at Victoria Beckham. Oh sorry, you can't: she is now completely invisible to the naked eye.

Since giving birth to Bronx and Shylock, she has gone from slim to skinny to skeletal.

If she has any more kids, which she keeps threatening to do whenever she gets within squawking range of a microphone, the poor little thing will disappear altogether. And then who will I have left to point and laugh at in a sneering superior manner?

Catherine Ryvita-Jones that's who. When she put on five stone during her last pregnancy and still looked fabulous in her Hollywood frocks, I applauded her. She had bosoms like watermelons in a vice and a bottom you could balance your pint on, but she looked - as Kate Beckinsale memorably said of Angelina Jolie - so good you could eat her with a spoon.

And when she had popped out the latest cleft-chinned, leek-wielding Douglas, she had the good grace not to immediately ping back into a size 10 before the midwife had said "it's a celebrity".

You know, I would bet my life savings (about £2.20 if you count the stamps in my purse) that some celebs - and I'm looking at you now Ms Hurley - insist that the poor midwife weighs them before they weigh the baby. "Yes, yes, she's 6lb 7oz, fan-flippin-tastic, but can I fit into my Versace?"

But anyway, back to CZJ. She sounds like the latest hormone replacement therapy, and, for decrepit old Michael, she probably is.

So, she pigged out while carrying Catatonia and didn't walk out of the delivery room and straight into a size 6 diamante mini-skirt and matching bustier. What's to hate about her; she sounds - dare I say - vaguely normal?

Well, unlike myself and some of my other post-natal friends (you know who I'm talking about girls), she has actually managed to get back into her size 10 frocks after months of sensible healthy eating and daily exercise.

We like to talk about getting fit and levering ourselves back into our favourite jeans without the use of an industrial jack. Unfortunately, however, these chats usually occur over a pizza (heavy on the cheese please Luigi), dough balls, cheesecake and several bottles of plonk.

Catherine, on the other hand, would probably be dancercising round the table and nibbling a green salad while we ate everything including the placemats. Which leaves me no option but to point and laugh at her in a sneering superior manner at every opportunity.

And no, it's not just sour grapes because she's snogged George Clooney and I haven't. There's still time.

Updated: 10:08 Monday, March 15, 2004