Immediately, I knew it was the right decision. I would be bendy and serene. My new party trick could be tying my ankles over my head. I would speak sagely to my peers about inner peace, spreading the joys of meditation and self-love. Later in life, I'd teach my grandchildren how to do the splits.

After a quick trawl on the internet, I found The Elbowroom yoga centre was right up my street (literally). They run 'Yoga Bootcamps'.

Reading through their philosophy, I felt my under-exercised heart pump quickly in anticipation. "Feel in awe of what you can do, " they said. "Kickstart your health program, shed pounds, get results." It was the ideal mechanism to catapult myself towards my eventual ambition: yoga guru (to the stars). Also, my recent skiing holiday had included a personal chef in my chalet, so I was feeling a little rounder than normal. Might drop one or two pounds, make it easier to tie myself in flexible little knots. I signed the dotted line.

THE WEEK BEFORE. . .

Ooh, goody. My confirmation of booking has arrived, along with a packing list, timetable and 'bootcamp rules'. I open the email and scan through the details.

If this was television, there would be an appalled silence right about now.

Good God. What have I done? I need chocolate. I nibble on a Twirl and brave another look.

The timetable is quite terrifying. All in all, over eight hours of exercise a day. The 'bootcamp rules' section warns against 'diva behaviour'!

It prohibits mobile-phone use during the day and includes a promise to search your bags in case you've sneaked in extra food.

And why would I sneak in extra food?

Because I was going on a wheat free, dairy free, caffeine free, alcohol free, sugar free, salt free detoxifying diet that would consist of just 1,000 calories for the entire day. I shut down the computer and stagger out of the office.

Mental state: Deeply traumatised.

Physical state: Vaguely nauseous but will manage spaghetti bolognese dinner all the same.

Spiritual state: Prayed for the first time in ages.

DAY ONE 8.30am: I add a third Oatabix to my breakfast bowl and pour in some porridge oats for good measure. All part of the padding process that I've been engaging in all week.

1pm: Work is mercifully busy so have no time to contemplate the fact that at 6.30pm I'm leaving for Bootcamp. Manage a large lunch and immediately begin fretting about what to have for dinner . . . the Bootcamp rules expressly state there will be no food served tonight.

Must, at all costs, avoid being hungry.

3pm: Need coffee to calm my nerves. While I'm waiting for the milk to be steamed (full fat latte, I deserve it), I see a Mars Bar Cake in the corner of my eye. Best get that too. Last chance to have chocolate for three whole days.

5.30pm: Not hungry at all but better eat. Can't be hungry later. A huge serving of pasta and lamb stew will do the job, topped up with some Belgian chocolate biscuits that are doing the rounds in the office.

6pm: Feel distinctly ill. Tummy uncomfortably full and distended. Nerves kicking in for real.

7.15pm: We arrive at Kippure Valley, Co Wicklow, and the countryside is just beautiful.

Inside the lodge incense is burning, the fire is roaring and herbal tea is being served to all the arriving guests. I feel a surge of hope and optimism. This is going to be a wonderful experience. I take one sip of peppermint tea and already feel cleansed and purified.

8.30pm: Everyone has arrived: 13 women, and two brave men, different ages, different sizes, varying levels of apprehension on their faces. We sit around and chat. There's a certain camaraderie in the air. Similar to the bond between deathrow prisoners.

8.45pm: The Weigh In. Having not weighed myself in over a year, I'm not overly concerned. Probably much the same as always, hovering under the 10-stone mark. I stand on the scales. Sweet Jesus. The week of padding clearly worked. For the first time in my life, I watch the little dial swing past 10. Just far enough for there to be no room for doubt.

9pm: The bootcamp organiser, Lisa Wilkinson, goes through the possible side effects of our detox diet. This includes headaches, a bad taste in the mouth, irritability and skin break outs.

I blithely don't take any notice. After all, I eat rather well on a daily basis so I'm not likely to suffer from any adverse reactions.

10pm: In bed. Not hungry at all, even though I haven't eaten for hours. Padding worked.

Good thinking by me.

10.10pm: I cannot believe I've put on weight.

This is why I don't own scales. Scales are evil.

Mental state: Rather depressed actually.

Physical state: Full. Really, really full.

Spiritual state: God? Well, clearly, there is no God.

DAY TWO 6.45am: I'm swimming in a sea of chocolate.

The clouds are made of marshmallows. A loud knock and cheerful voice drags me back to the bed in Wicklow. Time to get up.

7am: I gaze dolefully at my wardrobe. The Tribune photographer has refused my pleas to show up on Monday, when I will undoubtedly be super-slim and fabulous. Day off, he said.

Saturday morning or nothing, he said. So here I am, having been painfully enlightened by The Scales, trying to find something that might make me look decent while doing yoga.

Hmm. Just skintight leggings and clingy sport tops. May have been a bit premature with the packing list.

7.15am: Drinking hot water and lemon in the yoga room. Tummy rumbling. Hungry.

7.30am: Linda, our yoga instructor, starts us off. Feel optimistic again. I can do this. I bend down to touch my toes. My knuckles graze my knees. And don't go any further.

7.50am: Am bent double, staring through my legs, red faced and sweating, when I see the cheerful face of the photographer grinning through the glass door. My hope that he may have got lost in the mountains is dashed.

8am: My thigh muscles are trembling from the strain of holding myself in 'Warrior' pose, my poor little biceps are screaming at me. 'Downward dog' just isn't happening. And every time I bend, I grunt. Involuntarily. Extremely unbecoming.

9.30am: Finally, breakfast. I wait anxiously at the table, spoon at the ready. My heart sinks when I see my porridge. It only comes half way up the side of the bowl! And it's a small bowl.

I resovle to eat slowly, savour every bite.

9.31am: Finished.

9.32am: Seriously. Really. Is there seriously no more food?

10am: Time for the hike. No problem. Used to hike in the Girl Guides. Bit of an expert actually.

10.30am: He's bringing us up the side of a mountain. For the love of God, why?

12 noon: Gallantly holding my own. Not the last person to the summit. Not quite, anyway.

12.01: We get to eat our apple! Yay! Mmm. Food.

2pm: Back to the lodge. Legs ache. Arms ache.

And, unusually for me, head aches.

2.30pm: Lunch. Bowl of soup with lentils.

Entire meal comes to just 150 calories but is still surprisingly filling. Feel refreshed.

4.30pm: Headache growing. Strange taste in mouth.

5.15pm: Jog around the grounds. Most people opt to walk. But oh no, not me. I'm too busy being little miss 'give it everything I've got'.

Hurtle around the circuit twice with a very fit scuba-diving instructor and promptly collapse, gasping like fish on the shore.

7pm: An hour of pilates. Beyond exhausted.

Seeing double.

8pm: Dinner. Quinoa, salad, fennel and pears.

Tasty but hard work. We chew in silence, occasionally reminiscing about steaks.

9pm: Restorative yoga. So restorative that one person falls asleep and starts to snore. Cue hysterical giggles from the rest of us.

10pm: Bed. Head pounding but taking painkillers would ruin the detox.

Mental state: Good day. Good people. Feel virtuous and ridiculously healthy.

Physical state: Quite literally can hardly move.

Spiritual state: I am one with nature, following my hike. Lover of animals and plants.

DAY THREE 6.45am: Peel my eyes open. Shooting pain between my temples. Hmmm. Headache has morphed into extraordinarily painful migraine.

And me with no painkillers. Interesting.

7.30am: In absolutely foul humour. Trudge into yoga class, shoulders aching, barely able to bend my knees. Flop onto mat and shoot Linda my best evil look. Telepathic message:

do not dare ask me to exercise this morning.

7.31am: In demanding yoga posture.

7.45am: Seeing triple.

8.45am: Feeling a little more limber. Headache regressing a bit.

9.10am: Yay. Wrapped my hands around my feet . . . with straight legs! Clearly, I'm a natural.

9.30am: Mmm. Breakfast.

9.31am: Oh no. No way. It's smaller than yesterday.

9.32am: Finished. Still so hungry. Feel cheated.

And, to my complete horror, feel like crying.

9.35am: Can't take it. Ask for more. It's given cheerfully with a smile. Still, feel like Oliver.

10am: Another day, another hike. Really, really, really don't want to go. Tired, sore and incredibly moody. Occurs to me that perhaps I might be suffering . . . extensively suffering, in fact . . . from all the side effects of the detox.

11am: Yes, yes, beautiful views. But when are we stopping for the apple break?

1.30pm: First to arrive for lunch. Soup with tofu. Really yummy but for the first time I'm still hungry after eating.

2pm: Lying in bed. Awful humour is persisting.

It's Sunday afternoon. I should be nursing a hangover and ordering takeaway.

3pm: Time for some strange martial arts dancing. Why? Why the torture? I just want to sleep.

3.01pm: Weirdest thing. Was looking at yoga instructor David and his head turned into an Easter egg. My Flake Easter egg, so recently eaten.

3.30pm: Hmm. This martial arts dancing is quite fun actually. I almost did a handstand too.

3.45pm: Ok. Not running today.

5pm: Headache is gone, bad mood is gone and I'm not hungry. In fact, I feel brilliant. Wait anxiously for pilates class. Can't wait to become expert at that also.

7pm: Dinner. Chickpeas and brown rice. Yes, rice. Lovely carbs, how I missed you.

8pm: Yoga. Legs stretching and body bending in ways I didn't think possible.

9pm: We sit around, sip herbal tea and have a natter, our bright healthy faces glowing in the candlelight. Food still dominates the conversation.

10pm: Mmm. Bed.

Mental state: Much improved. Don't think I've lost weight but loving the yoga and pilates and feeling great in my own skin.

Physical state: Can hardly move. Sapped of energy but in a good way.

Spiritual state: I've hit a sort of eerie calm. A peace, if you will.

LAST DAY 6.45am: I bounce out of bed. Really looking forward to yoga. Getting the hang of it now.

7.45am: I can do the 'Downward Dog'. I knew it. I was flexible all along.

9.30am: Last breakfast. Same small size but today it's more than enough.

10am: Last hike. I'm at the top of the group, radiating energy and health.

12pm: Oh, no. No, please, no. They've taken out The Scales again.

12.15pm: Everyone looks so happy. One girl lost seven pounds and loads of people lost five.

12.20pm: The Weigh Out. I reluctantly step on the scales and gaze down.

12.21pm: No. Way.

12.22pm: Resisting the urge to do the chicken dance.

12.23pm: Ask me. Someone ask me how much I lost. I look around the empty grounds.

12.25pm: Lunch. I look around expectantly, waiting for someone to ask the question. And finally it happens. Oh, say I, looking modest, I lost nine pounds. In three days. Nine pounds in three days. Yes, that probably couldn't be healthy. But God almighty, it feels fantastic.

Mental state: Immensely proud.

Physical state: Every muscle feels tighter and harder than before. Body full of energy.

Spiritual state: Just about ready to start preaching love, peace and the joys of lentils to everyone I know. Tranquil. Serene. Wise.