Good intention shopping will be the ruin of us all. Overzealous stocking of the larder, buying into offers of two-for-one and bulk deals, plans to start cooking quinoa and kale; it’s why the term eat-the-fridge-down was invented and why we’re literally wasting billions on some seriously gourmet landfill.

I should know better. I wrote the book on home economics, quite literally, in my cookbook The Thrifty Kitchen, co-authored with my mother Suzanne Gibbs. Using up leftovers, smart shopping and virtous gastronomy is my thing. Friends will call asking for a recipe that uses all of half a cooked chicken, mashed kumera, half a litre of milk and three kiwi fruit, stat. Confession: Still my regular fridge purges involve throwing the half-used head of celery, a baby lettuce turned soggy, a whiffy chicken breasts we didn’t get to because we ate out most of last week.

In New South Wales alone, we throw away $848 million of fresh food a year, $694 million of leftovers, $371 million of packaged and long-life products, $231 million of drinks, $231 million in frozen food and $180 million of takeaways, according to the NSW Environment Protection Authority, a government body. The average NSW household throws away $1036 in food each year and 40 percent of the average Australian’s bin is made up of food waste, equating to $8 billion nationally.

When I was growing up a thick-set neighbor’s fridge was where food went to die. I’d open it hoping for soda but be faced with a pile of defeated vegetables and opened cans gilded with fuzzy green fur. She threw out nothing, plus she was the kind of person that would buy in bulk, especially items marked “quick sale”. She couldn’t keep up with the used-by dates and the onslaught of decay, but boy did she try. You wouldn’t catch us scraping mold from the cucumbers, but to her there was nothing so rotten that it couldn’t be eaten. It was people who were spoiled, not food.

Even my grandmother, cook Margaret Fulton, fell into the trap of eating everything and I’ve written a fictitious novella in my head around her during the depression, shooing off a swarm of flies on a decaying eggplant before sautéing it with lovely garlic. Once, truly, she made my mother eat the steamed cauliflower embedded with maggots, telling her not to be so fussy. Times were tough, and so was dinnertime.

Now, ridden with guilt, I throw out old, crestfallen food simply because aside from the compost bin I can’t see any takers. There’s another way, and here it is. First, don’t do big weekly grocery shops. Buy food and groceries that will cover one or two meals at the most. You’re just not going to use the family-pack cobs of corn in four days. Discover the beauty of the miscellaneous roast. Leftover veg is bulking out our bins. Two parsnips, one sad carrot, a baby fennel, half a radicchio from the weekend; together they lie forlorn in the crisper. Roasted in hearty chunks with olive oil, then drizzled in a dash of balsamic, fresh herbs, and you have lunches done for tomorrow.

Use those bulk places, but don’t buy bulk. If you only need 100 grams of puffed buckwheat and two tablespoons flaked coconut to make your favourite cereal, buy just that amount in a help-yourself bulk bin store. No more shelling out for a whole bag of chickpea flour you only need half of to make that gluten-free cake. You’re not a weevil farmer, after all.

In this era of nose-to-tail eating, by-catch seafood dinners and farmers markets, preventing food waste is as much about what you don’t buy as what you do eat.