Data Methodology

1. Data Provenance

Our foundational nutrition dataset is sourced directly from the U.S. Department of Agriculture (USDA) FoodData Central foundation database. Every food item on EatYay retains its canonical USDA record identification, raw nutrient values, and official food description. Restaurant menu nutrition items derive from verified brand disclosure datasets.

2. Standardized Mass Basis (Per 100 Grams)

To enable scientific, un-biased side-by-side comparison across disparate foods, all underlying nutrient records are stored and calculated on a standardized 100-gram mass basis. Household portion sizes (e.g., 1 cup, 1 medium fruit, 1 oz) scale dynamically from explicit USDA gram weights.

3. Daily Value (%DV) Calculations

Percent Daily Value (%DV) figures indicate how much a nutrient in a serving of food contributes to a daily diet, based on FDA reference daily intakes for a 2,000-calorie daily diet:

• Total Fat: 78 g
• Saturated Fat: 20 g
• Sodium: 2,300 mg
• Total Carbohydrates: 275 g
• Dietary Fiber: 28 g
• Protein: 50 g
• Potassium: 4,700 mg
• Calcium: 1,300 mg
• Iron: 18 mg

4. Strict Null Semantics (Unknown vs. Zero)

EatYay enforces strict null semantics. If a nutrient value was not reported or tested by the USDA for a specific food item, it is represented as null (displayed as Not available (—)). It is never assumed to be zero. In multi-ingredient recipe aggregation or side-by-side food comparisons, missing values propagate diagnostic status (Partial / Unavailable) rather than returning misleading zero sums.

5. Rounding Policy

Calculations maintain unrounded IEEE floating-point precision throughout internal processing. Display values round to one decimal place (0.1) for macro and micro values, and whole integers for calories and Daily Value percentages.