DAY THREE

Woken by whistle at 5.40am. Dear God. Still stars in sky as enter exercise barn at six for Stretch 'n' Move - hour and half of circuit training. Breakfast, then seven-mile hike around local area finishes me off. After lunch, life coaching workshop. All very interesting, am sure, but would listen to lecture on astrophysics at this point as long as could sit down, even if perched on gym ball.

Despite constant stretching, all now stiff from exercise and hobbling about. Looks like old people's home. Encouraged to think how hard we are exercising, from one (no effort) to 10 (very hard). Should be six to eight, but feel have spent past two days at about 20. Not sure how much more can take.

Tonight, line-dancing. Good laugh but never mind hoe-down; need lie-down. Another Cardio Blast and game of Crazy Cricket before bed. On way to barn for final session, see frogs mating on path. At least someone's having fun.

DAY FOUR

Whistle of doom sounds again, 5.40am. Stretch 'n' Move hard and only kept going on five-mile hike by company of others. Camaraderie very strong.

This afternoon, thank God, chance to sit down. Inspiring session with nutritional consultant Julia FitzGerald, deviser of week's menus. Can really see self sticking to her healthy recipes. Delicious. Lots of good advice. For me, big realisation that often confuse dehydration with hunger. Note to self: drink lots more water. Will help keep off wine too.

Blur of more exhausting exercise, then at 10pm find self alone in pantry, surrounded by food. Weirdly, am not tempted to swipe it. So far not really hungry or - astonishing - missing alcohol. Actually in pantry to use washing machine. Definitely sweatiest person in Devon. Leaving perspiration pools everywhere. Still, beats alcohol fumes.

DAY FIVE

Strange thing. Still hate early morning whistle but actually enjoy sweating to Burn Baby Burn and Oops Upside Your Head at 6am today. What's happening to me? Stretch 'n' Move definitely easier. Couldn't have managed this three days ago. Good feeling.

March along to Amy Winehouse on six-mile hike this morning. Cold sunshine, stunning countryside, feel euphoric. Maybe Amy should try retreat - can't imagine drugs give bigger high. Mood dips lunchtime when realise still have hours of exertion to go. By evening, ready to drop. Kept going by Denise Rose, 37-year-old from Reading, overweight since childhood and twice the weight she should be. Harder for her than anyone but never stops. Spurs me on, too.

DAY SIX

Draining nine-mile morning hike over Exmoor - practically licking tarmac as lean into horrifically steep final hill. Great sense of achievement at end.

Lunch followed by tai-chi next to lake at back of farm, accompanied by quacking ducks. Wonderful, but is only brief respite. Next, Bounce an Ounce - sounds fun but horribly testing abs-and-arms workout with gym balls.

Dinner, then repeat of games we did first night. Seems weeks ago. Afterwards, exercise workshop, helping us plan goals. Short-term aim? Survive week without dying. Also, might try to get through all the exercises in Stretch 'n' Move tomorrow without stopping once. Wonder if can.

DAY SEVEN

Last full day. Great boost when get through final Stretch 'n' Move with no stops, just as hoped. Am getting fitter.

This morning, repeat of the walk/jog/run from second day. Two minutes slower for me but no stopping this time, so feel good. Emotional moment when Denise crosses line. Lots of cheers. Group bonding is big part of week.