Every food tracker is only as good as the numbers behind it, and those numbers come from somewhere. Vital shows the source under each food so you can judge it, and flags entries that look wrong. This article explains where the numbers come from and why they can still be off.
Common foods: USDA FoodData Central
Vital bundles the USDA FoodData Central SR Legacy dataset, about 6,711 foods, so common foods search offline. It is published by the US Department of Agriculture and is in the public domain. Those values are reference averages: a lab measured samples of a food, and your chicken breast is not that sample. Cooked and raw versions differ a lot, which is why Vital asks which one you have.
Packaged foods: Open Food Facts
Barcode scans and packaged-food search use Open Food Facts, a free database that volunteers and food companies add to. Anyone can add or change a product, so an entry can be missing, out of date, for a different size or country, or typed in wrong. Open Food Facts itself gives no assurance that its data is accurate or complete, and the data is licensed under the Open Database License. Looking up a barcode sends only the barcode number, never a photo or anything about you.
Labels are not exact either
Even a correct label is an approximation. In the US, calories on a label are rounded, and the rules allow a margin before a label counts as wrong, so a label can differ from its own protein, fat and carbs and still be legal. Where the label counts fiber and sugar alcohols also changes the math, and the US and EU treat carbohydrate differently.
How Vital checks a barcode result
Protein and carbohydrate give about 4 calories a gram and fat about 9. When Vital reads a product, it adds those up (adjusting for fiber and alcohol when the record has them) and compares the total with the calories listed. If the two are far apart, Vital shows a notice before you log it, shows where the numbers came from, and lets you edit them. A number you edit is marked as yours.
The check is a smoke detector, not a guarantee. It catches an entry whose calories do not match its own macros. It cannot catch a product whose calories and macros are consistently wrong, or the wrong product entirely.
What to do when it matters
- Check the package against the screen, especially for a food you eat often.
- Edit the numbers before you log, or save the food as one of your own.
- If a number is wrong and Vital did not warn you, email support@vitalmacro.com with the product name or barcode and what the label says.
Sources
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central. Public domain (CC0 1.0).
- Open Food Facts and its terms of use. Database under the Open Database License (ODbL).
- US energy factors and label rules: 21 CFR 101.9 (Code of Federal Regulations, Nutrition labeling of food).
Written November 5, 2026. This is general information, not medical advice. Talk to a doctor or dietitian before big changes to how you eat or train, especially with a medical condition or a history of disordered eating.