Dataset

Weighed-Meal Reference Set v1.0 (mini-180)

Published April 14, 2026 · License: CC BY 4.0

Description

The Weighed-Meal Reference Set v1.0 (mini-180) is the Initiative’s primary reference set for validation work on dietary assessment applications. It comprises 180 meals prepared in a metabolic kitchen between October 2025 and March 2026. Each meal has an ingredient-by-ingredient breakdown with weighed grams, a mapping of each ingredient to a USDA FoodData Central (FDC) Foundation Foods entry, and a computed per-meal kcal ground truth derived deterministically from those two inputs.

The set is deliberately stratified across three cuisine buckets, drawing on the Initiative’s Cuisine Classification Codebook v1.1:

The 42 meals in the “Unassigned / prep variants” row include preparation-mode variants of the same dish (e.g., baked vs pan-fried) that were retained in the set for photo-capture coverage but are not assigned a primary cuisine bucket.

The set is released in two layers. The tabular layer (ingredient weights, FDC IDs, computed kcal, meal metadata) is released openly under CC BY 4.0. The photographic layer (overhead photographs of each plated meal under controlled lighting) is released under a restricted-access procedure because participant consent for the imagery was conditioned on researcher-use-only distribution.

Schema

Each meal is described by the following fields:

File formats: CSV (flat, one row per ingredient, with meal metadata repeated) and JSON (nested, one object per meal). Both formats are released together; content is identical.

Provenance / collection methodology

Meals were prepared in a metabolic kitchen by a team of three research dietitians following standardised recipes. Each ingredient was weighed on a calibrated balance (precision +/- 0.5 g) prior to plating. FDC Foundation Foods entries were resolved by the preparing dietitian and independently verified by a second dietitian; disagreements were adjudicated against FDC snapshot documentation. Per-meal kcal was computed deterministically from the weighed grams and the FDC entry’s per-100g energy value, with a composition-matching uncertainty half-width assigned per ingredient.

Photographs were captured under one of three standardised lighting conditions, on a neutral background, at a fixed overhead distance. Participants (the humans whose meals entered the set via donated recipes) consented to the imagery under a restricted-use agreement; no identifying elements appear in any photograph.

Known limitations

1. Cuisine coverage is narrow. Only three cuisine buckets are represented in v1.0; South Asian, Latin American, and Sub-Saharan African cuisines are not. A v2.0 expansion is planned.
2. Metabolic-kitchen setting. All meals are prepared in a controlled setting and do not reflect naturalistic meal variability. External validity to restaurant-served meals is limited — see the companion Restaurant Pilot Meal Set.
3. Portion-size distribution. Portions were calibrated to adult maintenance energy needs; the set undersamples very small (snack-sized) and very large (restaurant-sized) portions.
4. Photograph access. Photographs are restricted; purely computational work that needs imagery must go through the access procedure below.

Versioning

v1.0 is frozen as of the release date above. The canonical v1.0 file hash is published alongside the download link to permit verification. Errata, if any, will be documented in a v1.0.x patch release that does not change the meal set but may correct individual field values. A v2.0 expansion — adding South Asian and Latin American cuisine buckets, expanding to approximately N=300 — is projected for late 2026.

How to access

Tabular layer (open). CSV and JSON files are available directly from the Initiative’s datasets page. No request or agreement is required beyond the CC BY 4.0 attribution requirement.

Photographic layer (restricted). Researchers requiring access to the photographic layer should email the Initiative with (a) a brief description of the intended use, (b) affiliation, (c) confirmation of a suitable data-handling environment. A signed researcher use agreement is required; turnaround is typically within 10 working days. Redistribution of photographs is not permitted; derived products (e.g., trained models) may be published subject to the agreement’s terms.

How to cite

Rivera S, Patel M, Weiss H. (2026). Weighed-Meal Reference Set v1.0 (mini-180). The Dietary Assessment Initiative. https://dietaryassessmentinitiative.org/datasets/weighed-meal-reference-set-180/

License

The tabular layer is released under Creative Commons Attribution 4.0 International (CC BY 4.0). The photographic layer is released under a restricted researcher-use agreement and is not covered by the CC BY 4.0 license.