AT first I find myself reluctantly agreeing with Iain Duncan Smith.

When the Work and Pensions Secretary was challenged to live on £53 a week by benefits claimant David Bennett, the MP's response was "if I had to, I would".

So I'm relatively optimistic when I start five days of living on an equivalent amount to find out just how difficult it might be. After all, I live in a fairly cost-effective one-bedroom flat in Glasgow's west end surrounded by shops and rarely needing to drive anywhere,

Sticking to a daily budget of £7.57 for food and bills – excluding housing costs – will just mean cutting out expensive bought-sandwich lunches, and walking to work a bit more than usual, I think. With careful budgeting I might even be able to afford a couple of drinks or trip to the cinema.

A dose of reality kicks in when I sit down to calculate how much I will actually have to spend. Going through my monthly outgoings I chop out anything which I think I can live without – ranging from an expensive gym membership and the car to broadband and digital TV. That leaves electricity and gas, home insurance and the TV licence – which I decide to keep, given it is likely to be my main source of entertainment for the week. Scarily, that chops nearly one-third – £2.47 – off my £7.57 daily amount. But turning the heating off will save me 40p every day. I swither over the issue of home insurance at 80p a day before eventually deciding to keep it. That leaves me a grand daily total of £5.50.

On the first day I think I'm being frugal – but still manage to spend £1.30 on breakfast, £1.40 on travelling by subway into work, £1 on a roll, and £5.21 in the supermarket, the total of £8.91 coming in at just over my daily budget.

To compensate, the next day I manage not to spend anything by walking to and from work – a total of eight kilometres, which saves £2.80 on subway tickets – and steering clear of the shops at lunchtime. I'm doing very well, I think, until I realise I have forgotten to deduct the everyday bills I would still have to pay for the past two days. My healthy surplus of £6.23 has suddenly shrunk to £2.09.

A series of attacks were made on Bennett in the wake of the interview, with some claiming his true income is nearer £150. Whatever the exact details of that case, consumer charities point out some claimants exist on very little money.

In one case recorded by Citizens Advice Scotland a 59-year-old woman faced being left with £25 a week for food and travel after being told she would need to lose 25% of her housing benefit due to the "bedroom tax".

During the week, my breakfast has been porridge every day. I've relied on soup and rolls and pasta for lunches, while dinner has variously comprised of baked potatoes and beans, eggs and cheap pizza. I realise that purchasing a large amount at once would be the most efficient way to eat – but baulk at the thought of spending a large chunk of £53 in one go in case I run out of cash – and food – by the end of the five days.

Glasgow-based dietician Natalie Jones, a spokesperson for the British Dietetic Association, says while healthy food is not expensive, buying in bulk is often cheapest.

"It is a budgeting issue of whether you have enough to spend that week on something that could in theory last a month," she points out.

On the third day I stay within budget, but by the fourth day – after a long cold night with no heating – what started as a novelty is becoming a relentless grind.

I come across an account by Helen Goodman, Labour MP for Bishop Auckland, about her experience of living on £18 for a week, which she tried after being told by her constituents of the impact of welfare reforms. In a House of Commons debate in February she described how it left her hungry and sapped of energy.

"Most shocking of all was the fact that come Sunday I ran out of food—there was literally nothing left to eat that night," she told MPs.

I'm not quite at that stage, I'm thinking smugly, until I realise that Goodman had set aside £5 a week for basic non-food items. Technically, I should have done the same, with washing powder and bin bags among necessities I have put off buying until next week. That leaves me with 50p for the day. I defiantly spend it on a cake.

Evidence shows the stress of having to live on a low income does contribute to mental-health problems, points out Tom Pollard, senior policy and campaigns officer at mental health charity, Mind. The increasing rhetoric around benefit claimants being "scroungers" and "work-shy" also has a huge impact, he says.

"A huge number of people make reference to the fact they feel they shouldn't be on benefits because everyone thinks they are scroungers: that rhetoric around strivers versus skivers has really permeated into the conscience of people who are claiming benefits.

On the last day, I'm left with £3.70 to spend after finally succumbing to turning on the heating and forking out for a subway trip. It's not enough for a cinema ticket and I still have to buy food.

Tim Nichols, a spokesman for charity Child Poverty Action Group, points out that families can easily become trapped in a cycle of debt, often having to turn to loans with extortionate rates of interest.

Five days cannot of course reflect the reality of living on such a low income. I've had the benefit of escaping to a warm office every day and know there is money in the bank and an end in sight. Even so, when I consider if I could carry on for a month or longer, I don't see how anyone would choose living on benefits over work.