It's 11am and something is amiss. I'm sitting at my desk, mug in hand, but the mug is full of hot water and there's not a biscuit, muffin or ricecake in sight.
My stomach grumbles, demanding to know what's delaying its mid-morning pick-me-up of sugar. But all I can do is pat it disconsolately and reassure it that tomorrow normal service will be resumed.
Today, however, there will be nothing entering my tum until 7pm when I'll have one-third of a tub of soup, a small salad and 10 grapes.
It's my first day trying a 'fast' day of the 5:2 Diet or 'Fast Diet' and there's no two ways about it – I'm hungry.
Over the years, I've tried a lot of slimming plans, counting points on Weight Watchers, chowing down lean meats on Dukan and munching on vile combinations of cottage cheese and beetroot on the British Heart Foundation plan, forever fluctuating between 10 stone and, at my heaviest, 12.
The appeal of the 5:2 Diet is that it's essentially only a diet for two days a week – five days a week I can eat what I want; no foods are banned. I just have to commit to two non-consecutive 24-hour periods of slashing my intake to 500 calories. Simple.
Except that I swiftly realise I've no idea how many calories are in anything. Under the assumption that it's low-cal, I sit down to my normal breakfast of boiled egg, buttered toast and coffee only to discover nearly 200 calories – gone.
Mid-afternoon sees me pacing Tesco mumbling like a mad woman as I read food labels in horror.
"107 calories in a Kit Kat, well I never . . . 90 calories in a fat-free yogurt! Hmm, for another 17 I could have a Kit Kat . . ." and so went my shopping experience, until I established that I could have a chicken salad with 100g of tomatoes and 10 grapes, so long as I only ate one third of my tub of soup at dinner.
Oddly, working out the mathematics of fasting was more tiring than the lack of food itself.
Yes, I felt a bit morose missing elevenses, lunch and my afternoon snack. It was a pain having to work out the calorie content of everything (thank God for the MyFitnessPal app) and I hit a real low point eating soup with a tea spoon to make it last longer while my husband munched gleefully on a meat pie. Nor will calling 10 grapes "dessert" make it so.
But, actually, as diets go, it wasn't the worst. I wasn't bloated, had enough energy to go for a jog and the day's meagreness seemed manageable because tomorrow I could eat what I wanted.
Interestingly, at 11am the following day, I didn't want my traditional mid-morning snack. On reflection, it's habit, not hunger that prompts a lot of my daily calorific intake.
More importantly, the scales said I was down four pounds after just one day. Is intermittent fasting sustainable long-term? Only time will tell, but the short-term results are certainly food for thought.