Method and sources
Where Renalday's numbers come from, and how each one is checked.
The food tables
| Country | Table | Licence |
|---|---|---|
| United States | USDA FoodData Central: SR Legacy (2018), Foundation Foods (April 2026), FNDDS (2024) and Branded Foods (April 2026, barcodes) | Public domain (CC0 1.0) |
| Canada | Canadian Nutrient File 2026, Health Canada | Open Government Licence – Canada |
| United Kingdom | McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID) 2021 | Open Government Licence v3.0, © Crown copyright |
Each table is used only in its own country. Renalday never fills a missing value in one table with a value from another. None of these agencies reviewed or endorsed Renalday.
How values are checked
- The app's food files are generated from the official downloads. A second program, written separately, reads the same official files in a different way and compares every value of every food; if a single value differs, the build stops.
- Samples of foods are compared by hand with each agency's own website.
- Missing values stay missing. "Trace" is shown as trace; "less than" is shown as "less than"; UK values marked "N" (present but not measured) are shown as "Not measured".
- Food values are averages from each table. The food on your plate can be different. For packaged foods, the label of your product comes first.
What Renalday does not do
- It does not set, suggest or change targets.
- It does not interpret lab results, blood pressure or weight.
- It does not calculate doses of any medicine.
- It does not estimate how much potassium is lost by soaking or boiling. When a table measured a boiled food, Renalday shows that food.