It begins. This morning I splashed five parts water onto one part silty, vanilla-scented Huel as instructed. It’s a thin, beige, oaty-sweet mixture, 150 calories stretched across the best part of a litre. If I learn one thing this week it’ll be why Oliver Twist wanted more.Wildly increasing the relative amount of Huel to water stopped me expiring of hunger later in the day, but in the absence of a blender – you have to furiously shake the branded beaker like a baby with a rattle – this makes it fairly lumpy. Still, I’m full and feel fine, and if my colleagues think I’m a weirdo for doing this, none of them have said so.

I head to the pub after work – a problem. All I'm allowing myself to put in my mouth is Huel and water. Do I sup brazenly on my beaker? Or do I ask for water and put some shrapnel in the tips pot?Realising that I’d have to turn down even a lemon slice, I hunker down with my trusty beaker and try to avoid the landlord's eye. It’s going to be a long old week.

I’m struggling to get enough down me to hit anywhere near my 2000-calorie RDA, and feel a bit off the pace playing five-a-side football. But I’m always off the pace, and I’ve felt full all day.Interestingly, I don’t experience my usual vicious afternoon craving for Quavers. Am I cured?

Caved and had a ginger nut. Oops. In my defence, I’ve lost three kilos in three days (albeit mostly just through not having much food in my gut) and the scent of Huel is beginning to sicken me, making it even harder to chug enough down to keep me going. By mid-afternoon I feel fairly light-headed, and when a kind but unthinking colleague offers me a biscuit, I take it. I feel rejuvenated.

The Huel remains a little lumpy, but putting coffee powder in it this morning livened it up enough for me to start almost liking it again. And I don’t feel malnourished at all. In fact, I can say with absolute certainty that my current diet of Huel by mouth is far healthier than whatever I’d be gobbling down left to my own devices.

Someone on the other side of the office just opened a tub of curry from the Wasabi shop downstairs. I know because my sense of smell could rival a bloodhound’s after days without real food.There are mercies though. Huel forum users warn that days of flatulence and digestive problems await sudden adopters, but to everyone's relief I’ve escaped this unwanted side-effect. And that mixing in coffee powder for breakfast really helps. Savoury in the morning, sweet in the evening. Like a drawn-out main course and then pudding. Delicious.

The list of food which I am lusting after includes, but is not limited to: a colleague’s Cornish pasty; Mini Cheddars; a Quorn sandwich; red cabbage; and Quavers. I even half-fancy some lettuce.I turned veggie a couple of years ago and this is the closest I’ve come to running into the nearest KFC, slapping a tenner on the counter, and demanding a Boneless Banquet with extra gravy. Is this what it's like to be pregnant?It all gets too frustrating after another unfulfilling pub trip: I wolf down some noodles on my return home. Sorry, Huel. Sorry, journalism. Sorry, science.

Having had something different the night before, the last day is a breeze. A week to the hour since my last full meal, my flatmate and I usher in a pizza delivery. It’s bready and flavourless and she bins most of hers – Hearn and Collier would despair at her wastefulness – but I make short work of mine. At last! Real food! I devour the pathetic excuse for a pizza like a wolf tearing through a flock of lambs.