Mains — Data sources and attribution
Mains's food data comes from three places: the catalog we ship, Open Food Facts, and the foods you create yourself. This page credits the first two and states their licence terms.
USDA FoodData Central — public domain
Mains's built-in food catalog is derived from FoodData Central, published by the U.S. Department of Agriculture, Agricultural Research Service (fdc.nal.usda.gov).
FoodData Central is a work of the U.S. Government and is in the public domain in the United States. No permission is required to use it; USDA is credited here because a user is entitled to know whether a number was measured in a laboratory or modelled from a survey.
Three FoodData Central datasets are ingested, and the app distinguishes between them because they differ in how the numbers were produced:
| Dataset | Release used | What it is | How Mains labels it |
|---|---|---|---|
| SR Legacy | 2018-04 | The legacy Standard Reference: laboratory-analysed generic foods. | “USDA”, shown as a verified entry |
| Foundation Foods | 2026-04-30 | Newer laboratory analyses with full provenance metadata. | “USDA”, shown as a verified entry |
| FNDDS (Survey Foods) | 2024-10-31 (survey window 2021–2023) | Prepared dishes whose nutrients are modelled from ingredient profiles through survey recipes with yield and retention factors — nobody measured “Pad Thai, NFS” in a laboratory. | “USDA”, shown as modelled, not verified |
Mains is not endorsed by, affiliated with, or certified by the USDA. The macro figures shown in the app may have been adjusted from the published values where USDA's own data contains a documented defect (for example, rows whose stated energy cannot be reconciled with their stated macronutrients); those adjustments are ours, not USDA's.
Open Food Facts — Open Database License (ODbL 1.0)
Packaged and branded products come from Open Food Facts (world.openfoodfacts.org), a collaborative, free and open database built by volunteers.
Open Food Facts data is made available under the Open Database License (ODbL) v1.0 (opendatacommons.org/licenses/odbl/1-0/). The individual product contents are available under the Database Contents License v1.0 (opendatacommons.org/licenses/dbcl/1-0/).
What that means here, in plain terms:
- Any Open Food Facts data you see in Mains remains available under ODbL from Open Food Facts.
- You are free to use, modify and redistribute that data yourself under the same licence.
- Where Mains shows an Open Food Facts product, it is marked as such in the app, and the mark travels with the entry into your diary so the source is still visible weeks later.
Open Food Facts data is community-entered and is not verified by Mains or by Open Food Facts. Mains discards rows that are physically impossible and shows at most three suggestions, but a plausible-looking number can still be wrong. Check the package.
Open Food Facts is contacted directly by your device, not through our servers; see the privacy policy §4.5 for what that request carries.
Open-source software
Mains is built on React Native, Expo, PowerSync, SQLite and a number of other open-source components, each under its own licence (predominantly MIT and Apache-2.0). A full dependency listing is available on request from support@mains.app.