Five years ago, I undertook the Mastercheap challenge: trying to eat a healthy (enough) diet with a weekly budget of $25 and an entirely empty pantry. Would that still be possible in 2015 -- and which supermarket would offer the best deal? Let's find out.

Few people would force themselves to eat for a week on a $25 budget, with only basic ingredients allowed, no existing pantry supplies permitted either and no taking freebies from others, which is what I just did for Mastercheap Raw. But while the process might be extreme, everyone can learn something from the experience and plan their food shopping budgets better.

I'm seated at a media launch at Otto Ristorante, one of Sydney's more exclusive restaurants. Options on the menu include eye fillet of Angus reserve beef and red wine rigatoni with a pork sausage ragu and buffalo ricotta. It's all utterly tempting, and that's before the waiter recites the specials. But I'm not paying attention, because I can't eat any of it. Those are the rules for Mastercheap Raw.

There are only 17 items on the $25 Mastercheap Raw shopping list, so in a sense every one of them is a "hero ingredient": take one out and the whole week would instantly look a lot bleaker. But if I had to pick a single vital element that shows up in almost every meal, it would be the humble container of table spread (that's margarine to most of us).

When I first did Mastercheap back in 2010, when people asked me "How are you coping? Are you hungry all the time?" I could honestly answer "Really well" and "No". If I got asked those questions right now during Mastercheap Raw, I would have to prevaricate slightly. And the reason is mostly carbs.

Day 4 of Mastercheap Raw. Past the halfway point. This can't be called suffering. I'm eating three meals a day and getting plenty of vegetables and protein. But at this stage, the notion that "doing it yourself" delivers better results is not convincing. For that to be true, you need a bigger budget. And one thing I'm learning in this experiment is that very few people actually pay attention to what stuff really costs.

Day 3 of Mastercheap Raw saw me heading to the office and a media launch: how will I cope with co-workers stuffing their faces? Plus: I've spent the last 50 cents.

Day 2 of the Mastercheap Raw challenge was Sunday: no need to go anywhere, and a host of vegetable-centric dishes to prepare. But first let's talk about breakfast.

The Mastercheap Raw experiment has begun! I've spent my $25 and it's time to start actually cooking and eating. How much advance preparation am I going to need, and how will I cope with going to a fully-catered event on the very first day?

So I have $25 to feed myself for the week and I have to make more or less everything from scratch. What made it onto the Mastercheap Raw shopping list?

The Mastercheap project is back! Once again I have to survive with a total food budget of $25 for a week, and to add an extra challenge, this time I have to try and make everything from scratch. This is Mastercheap Raw. There will be many potatoes.

Live Below The Line challenges people to eat on $2 a day for five days to raise money for charity. Two years ago, I undertook the similarly-themed Mastercheap challenge. Can I adapt that $3.50 a day budget to work for even less?

It was a year ago that I embarked on the Mastercheap experiment -- feeding myself on a budget of just $25 for an entire week while maintaining a balanced diet. That proved to be much easier than many people anticipated, but it turns out I could have done it for even less money in the UK.

During Lifehacker's Mastercheap experiment, I reached the conclusion that house brand foods were often indistinguishable from their mainstream counterparts, despite only costing half as much. A cross-brand comparison by Choice goes one step further and suggests that in some categories store-brand products actually taste better than their big-brand rivals.

The main reason for my rush visit to Dubbo yesterday was to test how the wireless broadband worked. But while I was there, I also wanted to investigate how well the budget from the recent Mastercheap project I conducted to eat for a week for $25 would have worked if I happened to live there.

I came, I spent $25, and I didn't starve. But what lessons does Mastercheap hold for anyone trying to get better value from their shopping on an ongoing basis?

I square up to the final day of Mastercheap. It's a potentially tough thing to do on a Friday.

Today's Mastercheap menu includes fried eggs and a meat pie. Surprisingly, that doesn't completely blow out the energy totals.

Just how much difference would it have made to the Mastercheap project if I hadn't relied almost entirely on store brand products? An enormous amount, it turns out.