1. Primary source: USDA FoodData Central
The nutrition values for whole foods on this site come from USDA FoodData Central, the U.S. Department of Agriculture's public food composition database and one of the most rigorous nutrition references available. We use the Foundation Foods and SR Legacy data types, which contain laboratory-analyzed generic foods rather than branded products.
All USDA-backed values are presented per 100 grams of the edible portion. This keeps every food directly comparable and avoids the ambiguity of vague serving sizes like "one piece" or "one cup".
2. How foods are matched to USDA records
Every whole food in our database is manually mapped to a specific USDA record through its FDC ID, a unique identifier assigned by FoodData Central. When you open a food page, the calories, macronutrients, vitamins, and minerals are retrieved from that exact record via the official USDA API. We do not guess which record fits: each mapping is chosen to represent the most common raw or typical form of the food, and the page links back to FoodData Central so you can verify the numbers yourself.
3. Prepared and composite dishes are estimates
Dishes like pizza, lasagna, cocktails, and fast-food items do not have a single authoritative composition: every kitchen makes them differently. For these foods we publish AI-assisted estimates derived from standard recipes and published nutrition data, reviewed for plausibility before going live.
These entries are never presented as USDA data. Each one carries a visible "Estimated values" badge, uses a per-serving basis appropriate to the dish, and states its source as recipe-based estimation. We also do not publish vitamin and mineral values for prepared dishes, because those numbers would be too speculative to be useful.
4. Known limitations
- Natural variation: two apples are never identical. Ripeness, variety, season, and growing conditions all shift nutrient content.
- Preparation differences: cooking method, added fats, and trimming change the final values, especially for meat and fried foods.
- Estimated dishes: recipe-based values can differ meaningfully from the specific version on your plate. Treat them as a starting point, not a measurement.
- Not medical advice: all values are for general information. If you manage a medical condition through diet, rely on your healthcare provider, not on this site.
5. How errors are corrected
If you spot a value that looks wrong, tell us through the support page or by email at [email protected]. Reports go directly to the developer. We check the flagged value against the underlying USDA record or recipe data, fix incorrect FDC mappings, adjust estimates when better data exists, and update the page. The review date at the top of this page reflects the last time this methodology was checked end to end.
To learn more about who maintains this site, visit our about page.