From the start of my diet, I have been clear with myself: I will not try to be perfect, because this can only lead to failure, which leads to shame, which leads to a season with your head in the fridge, munching your way efficiently through the contents. The trouble is that, as with many aspects of my life, I have embraced imperfection with far too much gusto. "Oh," said my boyfriend the other day, as I explained that I couldn't have pie for lunch. "I had absolutely no idea you were still on a diet." Since we live together, this seemed a bad sign.

And so last week I decided to aim for seven days of perfection: I would walk into work, lay off the booze and eat carefully. With a little planning, I reasoned, this would be no problem at all.

On Monday I marched into work with a salad, and was promptly sent to Inverness for a story. I forgot the salad, and instead bought beef sandwiches at the airport - they looked so good that I didn't check the dietary details; whatever the damage, I really wanted to eat them. On returning home that night, I couldn't resist more reward for my rigours. I have been to Inverness and back in a day, I thought. The least I deserve is cake.

Tuesday was marred by eating chocolates in the office; on Wednesday I eschewed the chocolates, but went for one drink that turned into four; on Thursday I was hungover, so had an enormous bagel with peanut butter for breakfast; on Friday I had given up the ghost entirely and gulped down a fried egg sandwich, followed by heaped handfuls of pistachios.

"The trouble is," said my boyfriend "you don't really care about how you look, so it's difficult to get motivated." He's right. I try to dress well, and I hate being confronted by unfortunate photographs, but beyond that I'm sanguine. And yet, I would likely still be healthier, more active, if I weighed less. What can I say? My halo hasn't so much slipped as taken up residence around my ankles.