Three nutrients, three energy densities
Protein and carbohydrate each release roughly 4 kcal per gram; fat releases roughly 9 kcal per gram. Alcohol sits at about 7. These are conversion factors used in food composition tables, and they are the reason a small change in the fat content of a meal moves the calorie total more than the same change in carbohydrate.
That single fact explains most of the surprise people feel when they start logging. Two tablespoons of oil in a pan is a rounding error on the plate and around 200 kcal in the total. A large bowl of rice looks like the main event and often carries less.
What reference bodies actually publish
European reference values are given as ranges rather than single targets. Protein intake for healthy adults is expressed as a per-kilogram figure, carbohydrate and fat as a share of total energy. The ranges are wide on purpose: they describe populations, not individuals, and they are set to avoid deficiency rather than to optimise anything.
This is worth knowing before reading any macro split online. A '40/30/30' rule is not a scientific finding. It is one point inside a range that reference bodies deliberately left wide.
Why the split matters more than the total for some people
Two meals can carry the same energy and behave differently: in how full they leave you, how they fit around training, and how easy they are to repeat. Protein and fibre in particular tend to change how long a meal holds, which is why they show up in satiety research far more often than total calories do.
None of that makes the total irrelevant. It means the total answers one question, and the split answers a different one.
What this looks like when you log a meal
A logged meal that only shows calories hides the thing you would want to act on. Emira breaks a meal into its ingredients and shows where each number came from, whether that is a scanned product, a database entry or an estimate, so the split is inspectable rather than asserted.