# Why the app shows ranges

Needs, label values and portions are all imprecise. A single number would suggest a precision that does not exist.

## Your needs are an estimate

The app shows plus and minus 10% around the estimated value. The 10% follows the accuracy measure of a systematic review.[^1] That measure applies to resting expenditure. The factor for your everyday life adds more uncertainty, so your real needs can also lie outside the range.

## Labels are not exact either

Nutrient values vary naturally and with production. A European Commission guidance document gives these tolerances for food control, including measurement uncertainty:[^2]

| Content per 100 g | Carbohydrate, sugars, protein, fibre | Fat |
| --- | --- | --- |
| Under 10 g | ± 2 g[^2] | ± 1.5 g[^2] |
| 10 to 40 g | ± 20%[^2] | ± 20%[^2] |
| Over 40 g | ± 8 g[^2] | ± 8 g[^2] |

Example: if a label says 20 g of protein per 100 g, a measured value of 16 to 24 g is within tolerance.[^2]

## Portions are guesses

Without scales you estimate the amount, and a photo estimate stays rough too. That is why the app stores meals with a from-to value.

## What this means for you

Read ranges as a guide. A single day above or below the range says little and is not a judgement. How the estimate works is explained in [How much energy do I need?](https://kostenlos-abnehmen.de/en/wissen/energiebedarf).

## Sources

[^1]: [Frankenfield D et al.: Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc, 2005](https://pubmed.ncbi.nlm.nih.gov/15883556/)
[^2]: [European Commission: Guidance document on tolerances for nutrient values declared on a label, December 2012](https://food.ec.europa.eu/system/files/2016-10/labelling_nutrition-vitamins_minerals-guidance_tolerances_1212_en.pdf)

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Last updated: November 2026. This is general information and not medical advice.

Original article: https://kostenlos-abnehmen.de/en/wissen/spannen