What are the four sources, and what does each one mean?
A calorie figure has to come from somewhere, and the four places it can come from are not equally certain. IZeat names them in the record, one per item, and refuses a figure that names none. The names are plain: label, reference, user, estimate.
| Source | What it is | What it is worth |
|---|---|---|
| Label | The values printed on the pack, per 100 g or per serving, read from a photo or typed, scaled to what you ate | The producer's declaration for that product; kept as printed, checked by reading it back; not a measure of your portion |
| Reference | A standard food composition table applied to the grams you gave of a plain, unmixed food | The table's average for that food; as good as the weight you said and the state you named, raw or cooked |
| User | A figure you brought yourself: your recipe's total, a batch you computed, a value you trust | Yours; the record keeps it as you gave it and does not argue |
| Estimate | A figure reasoned out from what was known when nothing could be weighed or read: a portion cue, a dish description, a restaurant plate | Honest only because it says so; the row to redo first when a figure looks wrong |
Bottom line: the source is not a grade for the food, it is a note on the figure, and it is what lets you decide later which rows to trust.
The four are not a ranking of virtue. A label can be misread, and the values read back are how that is caught; a reference value is only as right as the grams and the state you said; an estimate that states its assumption is a legitimate row, not a failure. What the record refuses is the fifth kind, a guess dressed as a measurement.
How does a meal, and a day, take its source?
From its least certain item. A lunch of chicken you weighed, rice you weighed and a sauce nobody weighed is an estimated meal: two reference rows and one estimated row, and the meal is tagged estimated because that row is in it. The recording receipt says so once, on the meal, and each row keeps its own source in the record; when you read the day back, or correct the meal, and only some rows are estimates, the reply names them: "(estimated: sauce)". A meal whose rows are all from labels is tagged label; all from tables, reference values.
On the day page, a row estimated beside weighed ones carries an "estimate" mark on that row; the day card the assistant shows carries the source of every meal and every item. Nothing turns red for it; an estimate is a fact about the figure, rendered the same way as any other.
One rule sits under all four. IZeat never recomputes an item's calories from its macros. A label's calorie figure is stored as printed, even when 4 times the protein and carbohydrate plus 9 times the fat would give something else; the factors, 4, 4 and 9 kcal per gram from Annex XIV of Regulation (EU) No 1169/2011, read 14 September 2026, are used for one thing only, drawing the ring on the day card that shows the share of the day's energy from each macro. A gap between the printed energy and the macros is a cue to look at the pack again, not a correction the record makes on its own.
What does it look like in a real lunch?
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. The assistant is asked to name the source of each item when it calls IZeat: label when it read a pack, reference when it valued a plain food you weighed from a standard table, user when you gave the figure, estimate when it had to reason.
Lunch, said in a chat: "150 g of cooked basmati rice, a tin of tuna in water, the label says 99 kcal per 100 g and I had the whole 120 g, 10 g of olive oil, and my usual salad, about a bowl." The assistant is asked to check what your words leave open, here the salad's dressing, and calls IZeat once. The receipt names the four items with their quantities, tags the meal estimated, and gives the day so far. Each row keeps its source in the record: the rice from a reference table for 150 g, the tuna from the label scaled to 120 g, the oil from a reference table for the 10 g you named, the salad as an estimate that states the bowl it assumed. Ask for the day and the summary says "(estimated: salad)" beside the lunch.
A week later the tuna looks low. Ask "what is in last Tuesday's lunch?" and the assistant is asked to read the rows back from IZeat with their sources: the tuna row says label, so the figure is the pack's and the question is whether the pack was read right; the salad row says estimate, so that is the one to redo if the day matters. "I checked the tin: 145 g drained, not 120" corrects the row, and the earlier state stays in the meal's history.
What a source is not: the source says where a figure came from, not that it is right. A label can be misprinted, a table is an average, your own figure is yours, and an estimate is an estimate. What the source gives you is the next question to ask, and a record where you can tell the four apart is the difference between fixing one row and starting the week again.
Frequently asked questions
Short answers to the questions people type, each one sourced above.
What does "source" mean in a calorie tracker?
Where a recorded figure came from. In IZeat each item carries one of four: label, the producer's printed values; reference, a standard food composition table applied to the grams you gave; user, a figure you brought yourself; estimate, a figure reasoned out from a portion cue or a dish description. The receipt and the day summary show it, and a meal is tagged with the least certain source among its rows.
Is a label more accurate than a reference table?
It is the producer's declaration for that product rather than an average for the food, so for a packaged item it is the figure to use; it is not a measurement of your portion, and it can be misread or, rarely, misprinted. The assistant is asked to read the values back before recording, which is where a misread is caught. A reference value is the right source for a plain food you weighed, and only as good as the weight and the state you said.
What does "estimated" mean on my day?
That at least one row of that meal was reasoned out rather than read or looked up for a weight you gave: a bowl of salad, a restaurant plate, a slice whose size was assumed. The day summary names which rows when the others are firmer. It is a note on the figure, rendered like any other; nothing turns red. It is also the first row to redo when a day looks wrong.
Does IZeat calculate calories from protein, carbs and fat?
No. An item's calories are stored as the label printed them, as the table gives them, as you gave them or as the assistant estimated them, and never recomputed from the macros. The 4, 4 and 9 kcal per gram of the labelling regulation are used for one thing: drawing the share of the day's energy that came from each macro. A gap between a label's energy and its macros is a cue to look at the pack, not a correction.
What is a "user" source?
A figure you brought yourself and asked to have recorded as given: the total of a recipe you computed, a batch you weighed and divided, a value from a source you trust. IZeat keeps it as yours and does not argue with it. It is distinct from a reference value, which the assistant looks up in a standard table for a plain food you weighed, and from an estimate, which the assistant reasoned out.
Can I see the source of each item later?
Yes. Ask the assistant what a meal contains: it is asked to read the rows back from IZeat with their sources; open the day in the web app and each meal shows its rows, the quantities, your own measure where one was converted, and the estimated rows flagged beside firmer ones. The export carries the source of every item too, so a spreadsheet can sort a month by it.