An average is useful for describing a set of measurements. It is not proof that every individual portion contains precisely that amount. USDA’s Foundation Foods documentation makes sample information and variation part of the data context.
A simple sample example
Imagine three invented measurements for the same stated nutrient basis: 8, 10 and 12 g. Their mean is (8 + 10 + 12) ÷ 3 = 10 g. The range is 8–12 g. If you report only 10, you communicate the centre of those examples but hide the variation.
Do not turn a range into a personal reading
You cannot know which sample your lunch resembles merely by choosing the average. Nor can you treat the highest or lowest sample as the guaranteed content of your order. A measured portion, a recipe calculation and a published mean are different evidence types.
Preserve the basis and method
An average per 100 g should stay attached to that food description and preparation state. Multiplying it by a weighed amount can give a useful estimate, but extra decimal places do not remove the underlying variation. A 137 g portion calculated from 10 g per 100 g gives 13.7 g under that simple assumption; it is not a direct laboratory measurement of your plate.
For everyday use, a documented estimate is often more honest than false exactness. When a published source gives sample counts or variability, keep them rather than rewriting the number as a universal property of the food. The figures above are fictional and explain statistics only; they are not measurements of any ingredient in GetMacros.
Sources and example boundaries
- USDA: Foundation Foods documentation
Food descriptions, portions, missing nutrients and sample variation.
All food figures and prices in the worked example are invented to explain the method. They are not restaurant nutrition, tested recipes, shopping prices or personal dietary advice. Use the current label for the product you actually have.