The most unreliable number in a food log is usually a restaurant meal, and this remains true when the restaurant publishes figures.
Why the official number is also an estimate
A published figure describes a standardised recipe. What arrives at your table is one execution of that recipe, by one cook, on one shift, with the oil poured by hand.
The variation is not random in its direction. Oil, butter, dressing and portion generosity all skew the same way, because a cook erring toward “more” produces a happier customer than one erring toward “less”.
The practical consequence for a log
Home-cooked, weighed: ±5% or better
Packaged, from the label: ±10% including rounding and reformulation risk
Restaurant, from a published figure: ±20–25% on execution variance alone
Which means one restaurant dinner can carry more uncertainty than the rest of the week combined. That is an argument for how to interpret the week, not for avoiding restaurants.
What to do about it
Use the published figure when it exists. It is the best anchor available and better than a guess.
Estimate high when it does not. The systematic errors all run one way.
Do not let one meal reshape your conclusions. If your week looks wrong and it contained two restaurant meals, the restaurants are the likeliest explanation and the least fixable one.
Where coverage decides it: if you eat out most days, an app that has the entry beats an app with better data that lacks it. That is the honest case for MyFitnessPal’s catalogue despite its measured error being the widest of the mainstream options — and it is why we tell chain-heavy eaters to stay there and verify.
Questions we get asked
How accurate are restaurant calorie counts?
Published figures are derived from a standardised recipe, and what arrives at your table is one execution of that recipe by one cook. Studies comparing served portions against published values find substantial variation in both directions, with a tendency toward under-declaration. Treat a restaurant figure as a central estimate with a wide band, not as a measurement.
How should I log a restaurant meal?
Use the restaurant's own published figure if it exists, because it is the best available anchor. If it does not, estimate deliberately high rather than low — the systematic errors in restaurant food (oil, butter, dressing, portion generosity) all run in the same direction. And do not let one restaurant meal reshape your week's conclusions.
Caleb Ostrowski
Editor · Stronger by Math
Coaches lifters and writes the arithmetic down. Nine years of client logs, most of them unglamorous. Buys every app on this site at retail and cancels most of them. No affiliate links anywhere on this desk.
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