Cooking too much is the most common source of leftovers nobody wants, and it happens because almost nobody measures the things that matter. A handful of rough numbers, held loosely, removes the guesswork and most of the waste with it.
Rough amounts, dry weight, per adult
Pasta: 75 to 100 grams. Rice or other grains: 60 to 75 grams. Potatoes: 200 to 250 grams. Dried pulses: 60 to 80 grams, which roughly doubles when cooked. Meat or fish: 120 to 180 grams boneless, less if the dish is full of other things. Vegetables: 200 to 300 grams across the meal, and it is difficult to overdo this one. Adjust upwards for people who have done something physical and downwards for a meal with several components. These are starting points, not rules.
Why everybody overshoots
Dry pasta and rice look like nothing in the packet and treble in the pan, so the eye is a bad judge of both. Meat looks like more when raw, so people under-buy that and over-buy everything else. Cooking for a household also drifts upwards over years as portions creep, and nobody recalibrates when a child leaves home or a habit changes.
Weigh the two that matter and eyeball the rest
Pasta and rice are worth weighing, because they are the ones that produce the sad tub in the fridge. Thirty seconds on a scale is the difference between dinner and dinner plus a portion nobody eats. Everything else can be judged by hand. A fist of grain, a palm of protein, two hands of vegetables per person is close enough for most meals.
When to cook extra on purpose
Deliberate extra is not waste, it is tomorrow’s lunch or next month’s dinner — but only if it is portioned and put away while you are still standing there. Extra that stays in the pan becomes waste on a delay. Things worth doubling: stews, sauces, beans, rice for frying, roasted vegetables. Things not worth doubling: anything crisp, anything dressed, anything fried.
Serve less and put the pan on the table
Plates are bigger than they were, and people finish what is in front of them. Serve slightly less than you think, leave the pan within reach, and let seconds be a choice rather than an obligation. What stays in the pan can be cooled and kept properly. What is scraped off a plate cannot.
Weigh the pasta and the rice, judge the rest by hand, cook extra only on purpose and portion it immediately. Most food waste is not a storage problem — it starts as a quantity decision half an hour earlier.