Fiona Barton: I wanted a change – so I gave up my job and my comforts

We are living on £140 a month, and there is no hot water. We are having a ball

"Change your life!", the ad man exhorts us daily. Buy a bigger car, switch deodorants, use another toilet cleaner, new brand, new you, the annoying jingles bray. Of course, we tell ourselves, as we reach for the credit card or turn on the latest makeover 'n tears TV show, it is all total nonsense. But, we cannot help but yearn for our lives to be transformed. And so four months ago, I did just that.

Not the essentials, I hasten to add: I am still married; a mother; daughter; sister; aunt; but I have stepped away from the life I once led to do "something worthwhile". "How brave", they all said when I announced my intention to abandon a generous salary, a successful career and a company sports car in order to live in the Third World as a volunteer. By which, most meant "How Insane" but only my parents were courageous enough to say it out loud.

I can still hear my father's incredulous voice when I rang, thrilled my husband and I had been accepted for a two-year placement with the charity Voluntary Service Overseas (VSO). "What? You are going to give up your job?" he said. "Yes, dad", I chirped, still high on the acceptance letter. "And you are going to give up your salary?" he asked. "Er, well that sort of goes with the job," I said. Uncomprehending silence followed but the unvoiced question "Why? (IN GOD'S NAME, WHY?)" was deafening down the phone line.

Why, indeed. I don't think it was a particularly virulent mid-life crisis, neither was it prompted by other seismic events, such as serious illness or the credit crisis. The reason – and it sounds so horribly smug that I have deleted the rest of this sentence twice already – is that we wanted to give something back. There, I've said it. My embarrassment is, I suppose, due to the fact that altruism is viewed with such cynicism by some. There is the lingering odour of Lady Muck about any act of "charidee", together with deep suspicions of the motives of anyone who acts without obvious – ie financial – rewards.

Examining our motives was hard enough for us but we decided that we were volunteering because we felt lucky. Lucky to have had happy, fulfilled lives, blessed with good health, adorable kids and a loving family. So was it middle-class guilt? A sort of atonement for that luck? I suppose there must have been an element of that, but we did not feel weighed down by our decision. There was an energy and fizz to our plans that was shared by other VSO volunteers- in-waiting we met.

As a group – I'm not sure what the collective noun for volunteers is, perhaps a perkiness? – we were about as disparate as it was possible to be. Yes, yes, there were some "brown rice and sandal" candidates, but in the main, we fitted no stereotypes. At the training sessions – in a former West Midlands convent – we were a room of singles and marrieds, between 30 and 60, and all professional (the VSO only recruits skilled professionals) all wanting to pass on our good fortune.

In 2006, the wonderful VSO sent 836 long-term volunteers to 34 countries and almost a third of them were, like us, over 50. The average age of the VSO volunteer is now 41 – the middle-aged are packing their rucksacks and setting off in their droves. We come from a generation of baby boomers and have been further liberated by worthless pensions, cheap travel and the advent of the "gap year".

We are, naturally, doing it our way – this is a grown-up world of volunteering, a long way from the newly commercialised gap year industry where our children pay through the nose to spend time with dolphins or elephants in the name of "saving the environment".

We spent years planning for the moment when our children would be old enough and our parents young enough to spare us for two years. That is not to say there were not protests and a few tears but, in the end, we got the nod from those most important to us.

So here I am, a Programme Adviser in a South Asian city, placed by VSO with a local organisation which brings together the media and the marginalised so that they can have a voice in how their society is run. I am having a ball, trying to impart my professional skills as a journalist at training workshops and making a documentary about refugees while my husband helps adults with learning disabilities.

We are (just about) living on £140 a month, shopping in the neighbourhood market rather than the expat supermarkets, and home is the ground floor of a local family's house. There is no hot water. I do the washing under a tap in the yard outside.

It is a life I am learning to relish although I realise that even the most talented adman would struggle to put a gloss on this new lifestyle brand.