The Nutrition Dex

The editorial reference for measurement accuracy in nutrition.

A working glossary of the terms that actually determine whether a calorie figure is credible: USDA FoodData Central releases, FDA label regulation, kitchen-scale precision, laboratory reference meals, and the statistical measures — MAE, MAPE, RMSE — that a serious publication uses instead of adjectives.

House rules

Numbers, not adjectives

"Accurate" is not a claim. Every accuracy assertion on this site carries an error figure (MAE, MAPE, or RMSE), a reference meal set, and the sample size that produced it.

Primary sources only

Entries cite the USDA FoodData Central release, the FDA regulation, the peer-reviewed paper. No blog-post authority, no re-reported figures.

Named alongside, not named alone

When a consumer app is mentioned, it's mentioned in a field of at least three, with each app's accuracy number attached. No endorsements.

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Editor's note

"I spent a decade reading food-policy copy that treated a calorie number as though it had been handed down from the manufacturer's lawyer rather than measured. The truth is shabbier and more interesting. A credible calorie figure is the end of a chain — Atwater factors, laboratory calorimetry, a specific USDA release, a regulated rounding rule, a kitchen scale with a tolerance printed on the box, a photo-logging model with a validated MAPE. This publication covers that chain, one term at a time."

— James Oliver, Editor