I'm sorry, I know this column is meant to be about exercise rather than diet (or dieting) and I know I banged on about food last week, but I'm going to do so again, for I am a woman obsessed. I have realised over the past stunningly physically unrewarding eight months, during which I have remained the same weight and increased my level of fitness by a measure that can only be reckoned in microns, that my failure derives from two things.

The first, as I have already documented in previous outpourings of resentful bile, is sloth.

The second has taken me more time to identify, but is no less deeply ingrained in what I increasingly miscall my character. It is the fact that I cannot be trusted around sweet food. I eat one Jaffa Cake, I eat the whole packet, and then happily move on to a family pack of Smarties and have to have my fingers prised off the crowning glory of a king-size Mars bar while I still have some blood left in my glucose stream.

So for the past six days - six long, long days - since I was vouchsafed this insight, not a grain of sugar has passed my lips. I have been mainlining cherry tomatoes, raspberries and strawberries instead, while carving hearts enclosing the words Cadbury Creme Egg into my desk. And anyone who says that raspberries and strawberries contain natural sugars is warned that I am not in the mood to respond to technical niceties. When I say I haven't eaten any sugar, you know what I mean. The white stuff, the refined stuff, the condensed, concentrated stuff, the stuff that - ideally - comes enriched with cocoa, hydrogenated vegetable fats and nougat. That stuff.

Yesterday I went to Sainsbury's and spent 20 minutes in the sweets and biscuits aisle, cradling bags of wine gums, licking Curly Wurly wrappers and entertaining vivid mental tableaux in which I lie on a hospital bed with eight liposuction tubes attached to each thigh, eating handfuls of Minstrels and sandwiches made of Fry's Turkish Delight between two slices of Fry's Turkish Delight - the perfect zero sum set-up for the fructose-dependent. And the bed is made of Flyte bars. And I'm reading Charlie and the Chocolate Factory.

Back in the real world, alas, all I can do is suck on a sodding strawberry.