⚡ Energy

Food energy is the fuel the body gets by breaking down fats, proteins and carbohydrates; it is measured in kilocalories (kcal) and kilojoules (kJ). Under EU rules, a gram of fat provides 9 kcal, and a gram of protein or carbohydrate 4 kcal. 100 g of whole milk contains about 60 kcal.

EU Regulation 1169/2011 sets these factors for labels: fat 37 kJ per gram, protein and carbohydrates 17 kJ each, alcohol 29 kJ, and dietary fibre 8 kJ. Packaging gives energy in both units, and one kilocalorie equals 4.184 kilojoules (FAO). As a benchmark, labels use the reference intake for an adult: 8,400 kJ, or 2,000 kcal a day.

In milk, energy comes from three components. According to USDA, 100 g of 3.25% whole milk contains 60 kcal, 3.3 g of protein, 3.2 g of fat and 4.6 g of carbohydrates, mostly lactose. Skimmed milk has almost no fat (0.08 g), but the protein and lactose remain, so it provides 34 kcal — a little more than half. The milk of some animals is far richer: reindeer milk, according to FAO, has about 16% fat and more than 190 kcal.

How much energy you need depends on age, sex, weight and activity. So EFSA gives no single figure for everyone but calculates needs by physical activity level. The 2,000 kcal on a label is only a benchmark for comparing foods, not a personal target.

Energy or calories? On food labels both appear: energy is shown in kilojoules and kilocalories, and one kilocalorie equals 4.184 kilojoules. This is food energy, the fuel the body gets by breaking down fat, protein and carbohydrates, not the energy of physics or of an electricity bill. Under EU rules a gram of fat gives 9 kcal, a gram of protein or carbohydrate 4 kcal. Whole milk has about 60 kcal per 100 g, skimmed milk 34.

In the nutrition table of a pack, look for the line “Energy”, given in kJ and kcal per 100 g. The EU requires both units, and Regulation 1169/2011 fixes the conversion factors. Milk with a higher fat content shows a higher number: whole milk about 60 kcal per 100 g, skimmed milk 34. Any shop that sells packaged dairy, from a supermarket to a corner grocer, shows it. Compare per 100 g, not per pack.

Why it matters to you. Compare foods by energy per 100 g: this shows that a glass (250 ml) of whole milk provides about 150 kcal, while skimmed milk gives roughly 85. Vitamins and minerals provide no energy — they do not appear in the EU table of factors. And the fat content of milk is the simplest key to its calorie value.