CarbTable practical guides
Where the numbers come from
Each CarbTable food links to a specific FoodData Central record. That record’s identity, nutrient values and documented portions are retained in our catalogue.
Different datasets have different purposes
SR Legacy is a historical food composition collection. Foundation Foods provides detailed data on selected foods. FNDDS describes foods and beverages reported in dietary surveys. We identify the dataset used for each food rather than presenting every record as a new laboratory measurement.
A dash is different from zero
A dash means the source does not report that nutrient. Zero is a reported numerical value. When a meal includes an unreported value, its total for that nutrient is marked incomplete.
Source dates and import dates are different
The source release identifies the dataset. Our import date records when the data entered CarbTable. Importing a historical record does not make the underlying analysis new.
Check the original description
Open the USDA link on a food page to see the original record. If a name, portion or nutrient seems inconsistent, prepare a data issue report with the food’s FDC ID and the value involved.
A worked example from the catalogue
Rice, white, cooked comes from FDC 168878, in SR Legacy, April 2018. The original description is “Rice, white, long-grain, regular, enriched, cooked”.
CarbTable imported this record on 2026-10-26. That import date does not replace the historical source release or claim a new nutrient analysis.
Check the original USDA record. Values here come from the same catalogue records used in the calculators.
Check the source
This guide explains how to use the reference data. Read the USDA documentation and CarbTable’s methodology.
Prepared by CarbTable, October 26, 2026. Editorial policy and review status. General information, not individualized dietary or medical advice.