I've written about food waste before, but as we are fast approaching that time in the year when resolutions are made and sometimes kept, it seems worth bringing up again.

Besides, this is a subject that is not going to go away. Perhaps I would have written about something else today had I not spoken to an elderly woman in Sainsbury's pushing a trolley filled with two of everything.

Two large bunches of bananas, two identical packets of biscuits, two bags of crisps, two bags of oranges, two packs of frozen chicken curry, and so on. My curiosity got the better of me.

"I have just got to ask you," I said, "why do you buy two of everything, I've never seen a trolley packed this way before?"

"Oh, they are the specials. Two-for-one bargains. I can't resist a bargain," she replied proudly.

"But are you going to eat all this before it goes off"? I asked as I noted the brown spots on the bananas, a sure sign they were already over-ripe, doubtless the reason they were on special offer.

"Oh no. I hardly ever finish everything, but if I throw the one away I didn't pay for, I haven't lost anything have I?" she replied.

She had a point. Nevertheless, I would have liked to have talked further about the impact food waste has on the environment, but she had already wandered off in the direction of a two-for-one cheese deal.

That episode really made me think. I accept that the younger generations who have grown up in a throwaway world might adopt that attitude, but when an elderly woman who had clearly lived through the war years thinks this way - that's scary stuff!

My friend's admission that she always buys far more than she needs during her once-a-week shop was equally worrying. It seems she always stocks up with extra food just in case she needs it. She finds it's cheaper to throw away the things that go off, rather than spend an hour travelling to the supermarket and back in the middle of a busy week if she hasn't got enough food. Have we really got to the point where time is more valuable than food?

d=3,3,1Supposing we do resolve to waste less food during 2008 - how are we going to go about it in order to reduce that 6.7million tonne mountain of waste food that's thrown out at an estimated cost of £8bn a year?

One of the most obvious ways of only buying what you need is to take time to plan the week's meals and write a shopping list which you resolve to stick to regardless of special offers. This will not only have a positive impact on the embedded energy costs of producing, packaging and transporting the food you buy - which is claimed to produce the equivalent of at least 15 million tonnes of carbon dioxide every year - it will save you money too.

Another tip is to make sure that you never go shopping when you are hungry. Research suggests that people buy far more food than they need if they have skipped lunch.

Once home from a shopping spree, sort out the fruits and vegetables, stacking those that will last longest - root vegetables and cabbage, for instance - into the bottom of the pile, with the more fragile on top so that they are used first. Any food left from the last shop that's still stored in the fridge should be put to the front so that it's used first.

Save any leftover cooked vegetables by freezing them in small plastic bags until you have accumulated enough to turn into a tasty vegetable soup.

Turn the chicken carcass into soup, so that all you throw away when the soup is made are the bare bones. This is easily done by covering the carcass with water, adding a few herbs and an onion or two and allowing to simmer with the lid on for a couple of hours. Remove the bones, picking off any meat that's still attached, then add a little rice, or a few lentils and any other vegetables you happen to have hanging around that need using up. It's so easy and ensures that very little is wasted. Added to which, home-made soup is a hundred times nicer than commercially made soup - it's cheaper too.

If you have a dish of mashed potatoes left over, try mixing them with a small tin of salmon to make fish cakes, or use them to top a shepherd's pie. Mashed potato freezes well, too, in fact most leftovers can be frozen if they haven't been left hanging around at room temperature for too long.

When buying bread, decide how much of it you need for immediate consumption and freeze the rest. If making sandwiches each day for the lunch box, wrap the number of slices you need on a daily basis in cling-film and freeze until required. Bread thaws quickly, especially if you have only frozen a couple of slices.

Our inclination to be generous when we are entertaining visitors accounts for a great deal of food waste. Not wanting to appear mean, we often prepare far too much food for a dinner party. It really is worth cutting back a little - the days of conspicuous consumption are coming to an end. Visitors will soon come to appreciate the sight of empty dishes at the end of the meal as much as you do.

At the moment, it's thought that every third bag of shopping we buy ends up in landfill, which is a terrible waste, particularly as around 20 per cent of climate change emissions are related to the production, processing, transport and storage of food.

Ensuring that all the food you buy ends up in people's stomachs rather than the bin will probably be one of the biggest contributions you can make towards halting the ever-increasing emissions that come from landfill sites.

It's up to all of us to help halt food waste - all it needs is a little more thought about what is placed in the shopping trolley, the larder and fridge and on the kitchen table.

By eating the contents of that third shopping bag rather than throwing it away, we could make a real difference. Let's resolve to do just that in 2008.