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?.
The app does not replace medical advice.