As fads go, it's not as bad as a piercing -- certainly not of a body part not immediately visible. It has not got the same impact as a ridiculous haircut, either. And it's definitely less violent than a tattoo. Still, when my eldest announced she had become a vegetarian (sorry, "a PESCAtarian, mum"), I felt a shot of angst all the same.

Where had I gone wrong? My carnivore-based meals are always home cooked and delicious. I can do mince 10 different ways and a chicken wouldn't know what might happen to itself in my kitchen. Little gambolling lambs don't last past lunchtime and moo-cows are only good for one thing: a hearty casserole or garlicky marinated steak.

Nothing in the child's upbringing propelled her towards this kind of a notion. Or me, either. I'm sticking it firmly under the heading of "Phase", like the tantrums when she was two, and the pink hair that was a latter rebellion, while carefully examining the wardrobe for signs of goth-like clothing.

She announced it with the skill of a government spin doctor. We were on holidays, sitting in the sun, probably with a few on board. Relaxed as you like. She outed herself there and then. It was to include fish "for the moment"; otherwise, nothing that had to be murdered for tea, thanks.

It was all very calm and thought out. She'd done the research, asked friends and got hold of recipes. We were to be "supportive". Right, well, of course. I mean, the last thing you'd want is to forbid it, lest the fish disappeared too.

But now, weeks in, the practicalities are beginning to annoy me. There are the separate meals for one. She says not to bother, she'll get something for herself, but you can't possibly trust it won't be a packet of crisps and a Mars Bar, can you? I had already become used to doing odd-ball options for the pernickety youngest (no sauces, nothing touching, nothing green).

I have developed a worrying protein obsession: is she getting enough? How will we know? I'm stuffing cheese into her, and beans. Trying to get her to eat an omelette for breakfast. She's, er, cool, thanks. She'll just have "whatever vegetables" I have with what we call dinner. Dinner is the meat, you understand. Veg is the accompaniment. You can't just have a backing singer without Beyonce, can you? A guitar without the band? So, I worry.

And have you seen the price of fish? I mean, we normally buy SOME every week, but this is ridiculous. I'm glad she'll eat it, but it's costing a bomb. She tells me horror stories of people who are vegans and the eating list is shorter than your little finger. So, fish is good, but expensive. Mind you, we're all eating a bit more of it, so that's something I suppose.

And we are finding new ways to do veg. We're roasting, sauteing, baking, steaming. We're finding that vegetable lasagne is very tasty actually and that a nice frittata is nothing to sneeze at. We're inadvertently helping the ozone (did you know cows' farts cause 51pc of greenhouse gases?).

Still, it's wearing, but I trust her decision. And, despite it all, I find myself with an unexpected feeling: pride. That moment when your kids make choices entirely independently, outside of your direction, and stick to them. Maybe she'll make us all a little bit healthier, and kinder, with her decision.

- Sinead Ryan