Dataset

USDA FoodData Central Foundation Foods derived kcal lookup (April 2026 snapshot)

Published April 14, 2026 · License: CC BY 4.0

Description

This dataset is a derived, flattened lookup table of per-100g energy (kcal) values for every USDA FoodData Central (FDC) Foundation Foods entry available in the April 2026 snapshot. It is published as a companion to the Initiative’s reference meal sets so that downstream users can reproduce kcal computations against a frozen FDC version rather than against a live FDC query, which may drift as FDC itself updates.

The intended use is as a pinned reference table. If you are reproducing results published by the Initiative against the Weighed-Meal Reference Set v1.0 (mini-180) or any related product released in April 2026, this table is the authoritative source of the per-ingredient kcal values used in those computations.

Schema

The table is a single CSV with one row per FDC Foundation Foods entry.

Provenance / collection methodology

The snapshot was retrieved from FDC on 2026-04-02 using the public FDC API, filtering to the Foundation Foods data type. For each entry, the per-100g kcal value was computed as follows: (a) if FDC supplied an Atwater-specific factor derivation, that value was used and kcal_basis set to atwater_specific; (b) otherwise, if FDC supplied Atwater-general components, kcal was computed from those components (atwater_general); (c) otherwise, the FDC-reported kcal value was carried through directly (fdc_reported). No kcal value was imputed or interpolated by the Initiative.

The retrieval script, query parameters, and raw FDC response hashes are archived alongside the CSV release for audit.

Known limitations

1. Foundation Foods only. The table does not cover FDC SR Legacy, Branded Foods, or Survey (FNDDS) data types. Users needing those data types should query FDC directly.
2. Snapshot drift. FDC updates its databases; any entry may have been revised in FDC after our 2026-04-02 retrieval. Do not merge this table with a current FDC query without re-pinning.
3. Edge cases. A small number of entries were flagged during retrieval. See the edge_case_flag field:
   • "missing_water": water content not reported; kcal still computed from Atwater components.
   • "negative_carb_by_difference": the carb-by-difference computation produced a small negative value; reported as zero with flag set.
   • "low_confidence_atwater": FDC annotation indicated low-confidence Atwater factors; kcal retained with flag.
4. Unit handling. All energy values are in kcal (thermochemical). kJ is not included in this snapshot.

Versioning

This is the April 2026 snapshot. It is frozen and will not be updated in place. Future snapshots will be released as separate dated products (e.g., “October 2026 snapshot”). Downstream reference sets released by the Initiative will explicitly name which snapshot they were computed against.

How to access

The CSV is available for direct open download from the Initiative’s datasets page. No access procedure or agreement is required beyond the CC BY 4.0 attribution requirement.

How to cite

Rivera S, Weiss H. (2026). USDA FoodData Central Foundation Foods derived kcal lookup (April 2026 snapshot). The Dietary Assessment Initiative.

When citing, please specify the snapshot date (April 2026) to disambiguate from future releases.

License

Creative Commons Attribution 4.0 International (CC BY 4.0). The underlying USDA FoodData Central data is in the public domain; the derived table structure, flags, and kcal derivation decisions are the contribution covered by CC BY 4.0.