Food calories and macronutrients

Because those are two states of the same food. 343 kcal is the dry grain, 92 is the porridge cooked from it. Boiling makes the grain absorb water and roughly triples its mass, while the calories neither appear nor disappear — they are simply spread over a larger mass. The practical rule: weigh what you actually eat and take the figure for that same state. If it is easier to count the dry grain, weigh it before cooking — 60 g of dry buckwheat is the same roughly 205 kcal as 180 g of the porridge made from it.

It depends on the food, not on the spoon, so there is no single answer. A tablespoon holds about 15 ml, and that is 21 g of honey (about 70 kcal), 14 g of vegetable oil (124 kcal), 8.8 g of flour (30 kcal) or 15 g of water (zero). For every food here you get both the weight of the spoon and its calories. Spoons are counted level: heaped, a dry food gives 20–50 % more depending on how well it holds a shape.

Because the 4-9-4 coefficients are a simplification. Fiber counts as carbohydrate but yields about 2 kcal per gram rather than 4, so for foods rich in it — legumes, bran, dried fruit — the formula undercounts. Alcohol works the other way: it gives 7 kcal per gram and belongs to none of the three macronutrients, which is why beer looks almost calorie-free by the formula. On top of that, reference values are themselves rounded. A 5–10 % discrepancy here is normal and does not mean the data is wrong.

Less accurate than they look. The spread between varieties, batches and cooking methods is usually wider than the difference of a few kilocalories between sources: the same cut of meat can vary twofold in fat, and potato starchiness depends on variety and storage time. On top of that, not everything eaten is absorbed — from nuts, for example, the body gets roughly 20 % less than the label says, because part of the fat stays inside unchewed cell walls. So a table is useful as a reference point and for comparing foods with each other, not as a counter accurate to the kilocalorie.

There is no single number: daily need depends on sex, age, weight, height and activity, and usually falls between 1600 and 3000 kcal. The 2000 kcal used here is a reference for judging the size of a portion — the same one printed on food packaging in Europe — not a recommendation for you personally. Your own figure is better estimated with a formula that uses your data, and then checked against reality: if your weight holds steady, you are eating about as much as you spend.

Far less than a cup of water — flour weighs about 0.59 g per milliliter, so a 240 ml cup holds roughly 142 g rather than 240. The reason is bulk density: air stays between the particles. Sugar comes out at about 204 g per cup, salt at 300, rice at 204. That is exactly why volume cannot be converted to weight through water: the error reaches one and a half times. For every food with a known density the weight of the spoon and the cup is computed here separately.