How we compute per-serving macros, and why they are not exact to the gram
Every recipe card in YouEat shows calories and a macro trio per serving. Those numbers drive the whole plan, so we work hard to keep them as close to reality as we can. It is also fair to say up front: this is food, not a laboratory. Here is how we arrive at the numbers and where their limits are.
Start from grams, never from “a cup”
Volume measures hide a lot of variance. A cup of flour can swing a fifth by weight. Every ingredient in a recipe is therefore kept in grams (or millilitres with a density), and everything downstream is computed from weight. Recipes that originally said “a cup” or “a spoon” are converted with a factor for that specific ingredient, not a universal one.
Where the nutrition values come from
Every ingredient carries a nutrition profile per 100 g: energy, protein, carbohydrates, fat and more. The profiles come from public food databases, chiefly USDA FoodData Central, with ingredients typical of Czech cooking filled in from other sources. A recipe is then a sum: grams × profile, divided by the number of servings.
Where the limits are
- ✓An average, not your product. A database describes a typical ingredient. The flour, yogurt or ham from your particular shop can differ by a few percent, processed foods by more.
- ✓Raw weight. We compute from ingredient weights before cooking. Water that evaporates and fat that renders do not change the totals: the serving is the same in sum, just smaller and denser.
- ✓Servings as written. The per-serving number is the total divided by the recipe’s serving count. If you dish out more than an average share, the number will not know.
“We want to be precise where we can and honest where we cannot.”
The YouEat team
How to work with the numbers
Treat them as a good estimate, not a lab report. In home cooking a deviation of around ten percent is normal even with careful weighing, and over the weekly average your plan tracks, the swings of single servings even out. If you follow macros for medical reasons, go by product labels and a professional’s advice; YouEat is a guide, not a medical tool.
Protein, carbs and fat each keep the same colour everywhere in the app, the trio that rings every plan and recipe. An example serving looks like this:
The short version: the number on the card is our best honest estimate from real ingredient data. Good enough to build a week around, and honest enough that you know where its edges are.