Count one food for seven days, not everything in the bin. A week is long enough to show a pattern because the quantity involved is small and steady: UK households threw away 65 kilograms of edible food per person in 2022, worth £260 at 2022 prices, which is £260 ÷ 52 = £5 a week and 65 kg ÷ 52 = 1.25 kilograms a week per person, in WRAP's UK food waste key facts. The condition that changes the answer is which food you pick: choose one that appears several times a week, or seven days will show nothing at all.

Pick one food, not the whole bin

The candidates are the ones that recur. In the 2022 UK data the edible food thrown away at home breaks down by weight into fresh vegetables and salad 28%, meals 12%, bakery 11%, dairy and eggs 9%, fresh fruit 8%, drinks 7% and meat and fish 6%, and the ten most wasted single items begin with fresh potatoes, meals, bread and milk (key facts). Pick from that list rather than from whichever item last caused an argument.

Agree a start date and a finish date before anything is written down. Seven consecutive days, one food, one unit. Slices, portions, items or grams all work; changing unit halfway does not.

Two people, two jobs, seven days

One person notices, the other records. The person who cooks is usually the first to see an item go uneaten, and the person who did not cook can write the entry without it reading as a confession. Swap on day four so neither role hardens.

Write three things per entry: the item, an approximate amount, and what was happening. "Both of us bought a loaf" is a redesignable fact. "Not sure" is a valid entry and should stay in the record. Do not retrieve anything from a bin, and follow the storage and date instructions on the product itself; this is a record of ordinary decisions.

An example week: bread, in slices and pounds

Here is the week in figures, with the arithmetic shown. Bakery is 11% of the 65 kilograms of edible food a UK person threw away in 2022, so 65 kg × 0.11 = 7.15 kilograms a year, and 7.15 kg ÷ 52 = 138 grams a week per person. Two people come to 2 × 138 g = 276 grams a week. An 800 gram loaf cut into 20 slices gives 800 ÷ 20 = 40 grams a slice, so 276 g ÷ 40 g is close to seven slices between two people in a week.

The value follows from the same source: £260 for 65 kilograms is £260 ÷ 65 = £4.00 a kilogram, so 0.276 kg × £4.00 = £1.10 a week, and £1.10 × 52 = £57 a year for two people. Seven slices is a number two people can count on a Sunday evening without weighing anything.

What seven days cannot show

A week of notes finds a routine. It does not measure a household's annual total, and it cannot be compared with an EU-wide figure, because the EU figure counts different things: EU food waste in 2023 was 58.2 million tonnes, around 130 kilograms per person, edible and inedible parts together, with households at 53% and 69 kilograms per inhabitant, per Eurostat's release of 16 October 2025.

A week with guests, illness or a changed rota is still a valid week — write the circumstance in the margin instead of discarding the entry. The same care applies to any headline you meet during the week, which is what reading a food-waste statistic properly is about.

Turn the reason into one change

On day seven, read the entries and pick the reason that appears most, not the food. The 2022 UK breakdown of edible food thrown away at home puts cooked, prepared or served too much at 25%, smelled or looked off at 22%, personal preference at 22% and past the date on the label at 17% (key facts). Each of those four points at a different change.

Write the agreement in three lines: what recurred, the one action and the moment it happens, and the same count you will repeat next week. Too much cooked points at portion sizes; two loaves point at one shared shopping list; a date-label entry points at storage and at how the pack was bought.

Split the work so that one person is not left both acting and checking, which is the fairness test set out in making a shared kitchen experiment fair. If no pattern repeats, keep counting for a second week rather than inventing one.

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