All food packaging now contains precise nutritional information. The energy content of food is stated in two units: Kilojoules (kJ) and kilocalories (kcal). The difference: the calorie is an obsolete unit and has been replaced in science by the new unit joule. However, calories are still used in everyday language rather than kilojoules. One kilocalorie corresponds to approximately 4.2 kilojoules. The Food Information Regulation contains reference values for an average adult. This is based on an energy quantity of 2,000 kcal per day.

The German Nutrition Society (DGE) recommends a daily energy intake of 2300 kcal for men and 1800 kcal for women as a guideline. The lower energy metabolism of women is due to the different composition of body tissue. Men usually have more muscle mass, less body fat and heavier bones than women. Men therefore burn more calories than women. People with special requirements such as athletes, sick people or pregnant women have different values for the recommended energy intake.