Something strange has happened to me. I feel repulsed by the idea of a coffee and a croissant. Instead I crave rare steak and salad even for breakfast; and I find it surprisingly easy to say no to alcohol.

What is more, I've hired a personal trainer and started enjoying circuit training. All of which is very disconcerting for someone who has started everyday with a black coffee and ended every day with a large glass of Malbec, ran irregularly and reluctantly and who has been a vegetarian for more than 20 years

So what explains this personality disorder? I spent a week at a retreat in Portugal. This wasn't a kick-back-and-get-pampered retreat. This was Purescapes, a wellbeing and fitness retreat founded by Canadian fitness expert Reza Niam and Portuguese environmentalist Susana Vidal.

Niam explains that the philosophy underpinning this unusual retreat is that wellbeing is achieved via a trio of elements: chemical (what we eat), physical (what we do and how we move our bodies) and mental (how much relaxation we take and how we deal with stress). "I believe if you get the balance right between these three then you achieve health and wellbeing," he says.

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This translates into a retreat programme based around scrumptious locally sourced organic food, a tough regime of fitness training and sporting activities, educational talks and hikes in beautiful countryside, some challenging yoga classes and relaxing massages.

A typical day starts promptly at 7am with Qi Gong, flowing stretching movements rather like Tai Chi, this is followed by circuit training - it is at this point you are glad that you didn't have any alcohol the night before. The circuits, and other fitness work, are based around seven basic movements; squatting, lunging, pushing, pulling, twisting, bending and walking.

There is no fancy gym equipment, the work-outs are done barefoot on the lawn with exercise balls and kettle bells. The exercise principles may be simple but the exercises are far from easy. We were all begging for mercy trying to do inch worms - walking on all fours moving first your hands then your feet.

Each morning after circuits we all sit down to a breakfast of cereals, fruit, yoghurt and eggs. All meals are taken together with the staff around a dining table on the veranda. At about 8.45 we head out on the day's activity - this could be a hike along the south-west Portuguese coast, kayaking to a deserted island or learning to surf.

A picnic lunch - usually salad - is provided on the activity. We return to the villa mid-afternoon for one-on-one personal training, massages or free time (spent playing tennis, swimming or crashed out face down in your room) before our 6pm Swasthya yoga lesson. The day then ends with a supper of salads with fish or meat and copious amounts of water at about 8pm.

There is no minimum fitness level and the programme can be adapted to suit everyone from overweight business types to elite athletes recovering from injury. But whatever your shape or state to get the most out of your stay you need to be willing to give everything a go. From getting on a surf board for the first time to tasting rare beef after 20 years as a vegetarian.

Ah yes, the beef. Everyone was raving about the beef, saying how it was the most amazing meat they'd ever tasted. It was freshly slaughtered, from a farm an hour away, grass reared, and apparently tasted sublime. For a vegetarian, against intensive farming techniques, I had no excuse.

I tried a five centimetre square of rare beef and I have to report it was amazing, absolutely amazing. Two days later I had the lamb and three days later I was the first in the queue for second helpings of steak burgers.

Not surprisingly I was rated a high-protein type when I had my metabolic type assessed by the nutritionist Melissa Drews. I function best on a high-protein low-carbohydrate diet. If you have never done it, it is worth having your metabolic type analysed, despite the tedious 100-plus questionnaire asking for details of everything from your ear colour to your anger levels. I have kept to the recommended diet since leaving the retreat and have lost 6kg in a month, feel much more energetic and suffer less from insomnia.

For me the retreat was ideal, although there were downsides: my caffeine withdrawal headache certainly spoilt the first few days, and although the Purescapes team have rented a gorgeous villa it is not a hotel so don't expect your bed to be turned down on an evening, room service or even a lock on the door.

And it is certainly not a spa - no manicures or facials here.

It is, though, an excellent opportunity to detox, get fit, lose some weight and change unhealthy habits. As Niam says: "It is about giving people who want to change, who want to be more healthy, a kick start."

In 2008/2009 Purescape retreats are planned in the Algarve, Lanzarote, and Girona. Prices range from £1,790 to £2,710 and include full board, all fitness instruction, classes and activities, and one massage. Extra massages cost £68 per hour and the metabolic typing test costs £54. Additional activities including golf or a visit to a nearby spa are available for an extra charge.

For more information: www.purescapes.co.uk

Carol Lewis flew to Faro with Easyjet - easyjet.com

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