What do a cup, a spoon and a piece actually weigh?
More than you would guess for some things and less for others, and the reference tables have measured it. In USDA FoodData Central, read 17 September 2026, a large egg is 50 g, a medium banana about 118 g without the peel, a cup of cooked white rice about 158 g, a cup of cooked spaghetti about 124 g not packed, a tablespoon of olive oil about 13.5 g, half a roasted chicken breast about 86 g, and a medium baked potato about 173 g.
Those weights are averages of the pieces the table measured, not of yours. A banana from your fruit bowl is somewhere between the small at 101 g and the large at 136 g; "medium" is a guess about it, and a fair one. The point of the list is that the guess has a number behind it, so the record can carry the number and say it was assumed.
| What you say | What the table gives | What the day carries |
|---|---|---|
| "A large egg" | 50 g | About 72 kcal, "a large egg" kept beside the 50 g, the size assumed and said |
| "A medium banana" | About 118 g, peeled | About 105 kcal, size assumed and said |
| "A cup of cooked rice" | About 158 g | About 205 kcal, the cup kept as said beside the grams, the portion marked as assumed |
| "A tablespoon of olive oil" | About 13.5 g | About 120 kcal, the one line that hides on the plate |
| "Half a chicken breast, roasted" | About 86 g | About 142 kcal, size assumed and said |
| "A medium baked potato" | About 173 g | About 160 kcal, size assumed and said |
Bottom line: a measure you can name has a weight the table knows; the record keeps both, and says which parts were assumed.
Where does the error hide when nothing is weighed?
In two places, mostly. The grain, because a heaped cup and a level one can differ by a fifth or more, as the packed and unpacked cups of spaghetti do in the same table, 151 g against 124 g, and the cooked weight varies with the cooking; and the cooking fat, because a tablespoon of oil is about 120 kcal and a generous pour is easily two. Vegetables, fruit and lean meat move the figure less per gram of error, so a rough size there costs a few dozen calories, not a few hundred.
The honest answer, then, is not to pretend the cup is a scale. It is to name the cup, count the spoons, and let the record mark the item as an estimate with its assumption written down. A day made of such items is a normal day in IZeat; it says which lines were estimated, and a week of them still shows the direction, which is often all a count is being kept for.
A label changes the picture even without a scale. A packaged food states its serving size in grams, and a yoghurt pot or a bar is one serving you did not have to weigh: photograph the label, say how many you had, and the assistant is asked to read the values back for you to check before recording them from the label. The label article walks through it.
What do you say, and what comes back?
IZeat is the calorie tracker inside ChatGPT, Claude or any other assistant. Tell the assistant you already use what you ate instead of searching for foods and entering them one by one. Quantities are recorded in grams or millilitres only, so the assistant converts what you said, a cup, a spoon, a piece, and keeps your words beside the grams; its protocol has it ask first for the easiest portion cue you can give, rather than a menu of choices, and state what it still assumed.
Breakfast, said from the kitchen: "Two large eggs scrambled in a teaspoon of butter, a slice of toast, and a small banana." Nothing to weigh: the eggs are 50 g each from the table, the teaspoon of butter about 5 g, a pat, the banana about 101 g peeled, and the toast is the one thing worth a question, since a slice can weigh half or twice another; the assistant is asked to check it, you say a thick one, about 40 g, and the receipt lists four items, the sources, the assumed sizes, and the day so far.
Dinner, with a pot shared: "Chicken curry, about a ladle and a half, with rice, a heaped cup." Following the protocol the assistant asks what the curry was cooked in and how much, you say two tablespoons of oil for the pot of four, and the record carries the rice at about 190 g cooked, the curry as an estimate that states the ladle and the share of the oil, marked as such. Ask "what is in my dinner?" and the assistant reads the rows back with their sources; if you later weigh a heaped cup once and find it is 200 g, say so, and the row is corrected with the day.
The honest limit: without a scale, the grain and the fat are estimates, and the day says so. If you buy one thing, a scale for those two items is where the numbers tighten most; everything else, a cup and a spoon and a size word cover well enough for the record to show the direction.
Frequently asked questions
Short answers to the questions people type, each one sourced above.
Can you count calories without weighing food?
Yes, with less precision and no less honesty, if the record says what was assumed. A cup, a spoon, a piece and a size word each have a gram weight in the reference tables: a large egg 50 g, a cup of cooked rice about 158 g, a tablespoon of oil about 13.5 g. Through IZeat, the assistant converts them, keeps your words, and marks the portion as an estimate; the day shows which lines were assumed.
How do you estimate portion sizes without a scale?
With the measure you have, said plainly: a level or heaped cup, a tablespoon, a small or large piece, half a breast, a ladle. The tables give each a weight, and the assistant is asked to start from the easiest cue you can give rather than a list of options. Name the fat separately, since it is the item that hides; a size word for vegetables and fruit is enough.
How many grams is a cup of rice?
About 158 g cooked for white long-grain rice, in USDA FoodData Central, which is about 205 kcal; a heaped cup can be a fifth more or beyond. Dry rice is a different number, about 185 g a cup in the same table and close to three times the calories for the same weight, so say cooked or dry. In IZeat the cup is converted to grams and kept as said, so a later weighing corrects the row in one sentence.
How much does a tablespoon of oil weigh?
About 13.5 g for olive oil in USDA FoodData Central, which is about 120 kcal; a teaspoon is about 4.5 g. It is the one item worth counting by the spoon even when nothing else is measured, because a pour from the bottle is easily more than one tablespoon and none of it shows on the plate. Say the spoons and what share of the pan was yours.
Is a photo of the plate better than guessing?
It names the dish and cannot see the weight or the oil, so no: the questions still have to be asked, and the assistant is asked to put them before any number is recorded. A photo of a label is different: the serving size is a weight the producer measured, and the values are read back for you to check. A sentence with a cup, a spoon and a size word beats a picture of the plate.
Does IZeat need a scale?
No. Quantities are recorded in grams or millilitres, and the assistant converts what you said, a cup, a spoon, a piece, from its own knowledge of the food, keeping your own words beside the grams. What was assumed is marked as an estimate, and the receipt shows it. A scale for the grain and the fat is where precision improves most, if you want it; nothing in the record requires one.