4 source levels – why each one matters
How Zutato makes the origin of every single nutrient value visible.
Published on
Not every value is equally certain.
When an app tells you "This banana has 18 mg of iron" – how does it know? Did someone measure it? Pulled from a table? Estimated? Calculated from other values?
In Zutato every single one of the 138 nutrient values carries its origin visibly – and you decide which tiers are good enough for you.
The four tiers
Measured
Pulled directly from a product label, an official nutrient database, or a lab analysis. The highest confidence tier.
Example: iron in whole-grain oats at 4.6 mg is measured – source: Bundeslebensmittelschlüssel (BLS) standard reference 3.02, code FE.
The concrete source is always shown on the value itself – currently the Bundeslebensmittelschlüssel maintained by the Max Rubner-Institut, with room to add further official databases later.
Calculated
Derived from other already-measured values. The formula is traceable:
kcal = protein × 4 + fat × 9 + carbs × 4
The result is only as good as its inputs – when the macros are measured, the calorie total is just as reliable.
Estimated
Transferred from a similar product or interpolated from the average of a food group. Useful when no direct measurements exist – but explicitly flagged with lower confidence.
User-reported
A user entered the value themselves. These values are private, never shown publicly, and not aggregated into shared statistics.
Confidence hierarchy
Every value in your logbook carries one of these four tiers, shown as a small color-coded label right next to the value.
Source filter – you decide
In settings you choose the minimum tier that gets shown at all:
- Measured only → maximum certainty, but big gaps (many micronutrients are not directly measured everywhere).
- Measured + Calculated → the default for most users.
- Measured + Calculated + Estimated → full coverage, including interpolated micros.
- All four → including your own entries.
So no app sells you a value as more trustworthy than it is – and you can still work with less certain values when that's good enough.