Calorie tracker with a barcode scanner: the diary side

Scanner versus tracker

Worth separating, because people search for one and need the other.

A scanner answers a question about a single food, right now. How many calories in this? It is a lookup and the interaction ends there.

A tracker accumulates those answers into a record. Its output is not a number but a pattern: where your calories come from, which meals run heavy, how the week compares to the last one.

Most people start wanting a scanner and discover the tracker is what changed anything. Almost nobody is genuinely surprised by the calorie content of a chocolate bar. Plenty of people are surprised to find a third of their intake arrives after 8pm.

What the diary shows

The day

Every item, grouped into breakfast, lunch, dinner and snacks, with a running total against your target and the macro split alongside. The meal grouping is the part that earns its place — it localises a problem to a slot rather than leaving you with a vague sense of eating too much.

The week

Seven days side by side, with the average. This is the number that corresponds to what your body is actually doing. Daily intake swings by hundreds of calories for entirely ordinary reasons, and reacting to a single high day is how people talk themselves out of a plan that was working.

The patterns

Things that only appear once there is a fortnight of data. Weekends running 600 calories above weekdays. Protein consistently short on days you eat out. An afternoon snack that quietly outweighs the lunch before it. None of these are visible on any single day.

Making a diary survive past week one

Log as you eat, not at bedtime. Reconstructing a day from memory reliably under-counts, and by the largest margin on exactly the items you would most want recorded.

Build a favourites list. Most people eat the same forty foods. Once your repeats are one tap, the daily cost of tracking collapses.

Log the bad days too. A diary with the heavy days missing is not a record, and its average is wrong in a specific, predictable direction.

Accept approximation away from home. A rough estimate for a restaurant meal is worth far more than an abandoned day. Perfectionism is the main cause of people quitting.

Judge fortnightly, not daily. Weight moves with water, salt, glycogen and hormones. Two weeks of data is the shortest window that means anything.

Reading a plateau correctly

The usual story: several weeks of steady loss, then it stops. Almost always one of four things, and none of them is a broken metabolism.

Intake crept up. Portions grow, logging gets looser, the odd item stops being recorded. This is by far the most common cause, and a week of strict logging will show it.

Expenditure fell. A lighter body costs less to move, and spontaneous movement quietly declines in a deficit. A 10 kg loss can reduce maintenance by 200–300 calories a day.

Water is masking it. Fat loss continues while water weight offsets it on the scale. A sudden overnight drop of a kilogram or two after a stall is the giveaway.

Not enough time has passed. Three weeks of a 300-calorie deficit is roughly 2 kg of fat, which normal water fluctuation can hide entirely.

The response is to tighten logging for a week before changing anything else. Cutting further on inaccurate data is how people end up hungry and no lighter.

Your data

Without an account, the diary lives in your browser and never reaches us — private, and lost if you clear your data or change device. With an account it syncs, and you can export the whole thing as a spreadsheet whenever you like. It is your record either way; we do not sell it and there is no advertising business here that would want it.

Start a diary — the diary itself is free and lives in your browser.