Kriterion vs Cronometer

Cronometer tracks the nutrients in your food as well as the calories. Kriterion does too. The difference is where each figure came from, what sets the number you are eating to, and what happens on the days you do not cook.

Where a number came from is its own fact

Two entries can both say eleven grams of protein and mean completely different things. One was measured in a laboratory. One came off the back of a packet. One is what somebody typed in three years ago. Most apps flatten all three into the same figure and let you assume the best.

Kriterion tags every entry with how its numbers were produced, and colours it accordingly: laboratory analysis, a manufacturer’s own label, a published restaurant menu, a community submission, a recipe you built. Something you typed yourself gets no badge at all, rather than an invented one. It is a small thing that changes how you read your own diary, because you can see at a glance which parts of today you should trust.

The same idea runs one level deeper. When a source never measured something, Kriterion says it was not measured rather than showing you a zero, and it tells you how many of the nutrients it looks for were actually reported for that food. A blank and a zero are different facts, and an app that quietly turns the first into the second is telling you your diet is worse or better than the evidence supports.

The number you are eating to

However carefully you count what went in, the count is only useful against a target, and the target is where the guessing usually happens. Nearly every app, Cronometer included, starts from a formula: your height, weight, age and sex give an estimated resting rate, and an activity setting multiplies it. That is a sensible starting point and it is also, for a lot of people, several hundred calories out.

Kriterion works the other way round. It compares what you logged against what the scales actually did over a rolling window, and derives your expenditure from the gap. Then it does two things nothing else in this comparison does: it publishes how confident it is, as an interval in calories that narrows as you log more, and it grades its own past predictions against your results and tells you if it has been running high or low.

It also says plainly what that interval cannot cover. If you under-report your food, the maths still works, it just works on the wrong numbers. No app can see around that, and we would rather say so than let the confidence interval imply otherwise.

The days you do not cook

Weighing ingredients is where careful tracking works best and it is also why careful trackers tend to fall apart at the weekend. Kriterion carries real menu items taken from the figures restaurants publish themselves, starting with the UK and Ireland and growing outwards, so a meal out is a logged meal rather than a guess or a gap. For a British user in particular, that is the difference between a diary that reflects the week and one that reflects Monday to Thursday.