What do calories measure?
The calorie count tells you how much energy is contained in a food product. The energy in food is sometimes also measured in units called joules. When people talk about calories or joules in connection with nutrition and diet, they really mean kilocalories (thousands of calories) or kilojoules (thousands of joules). The abbreviation for kilocalories is kcal. For kilojoules it’s kJ. Calories can be converted into joules – and vice versa – as follows:
- 1 kcal is equal to around 4.2 kJ.
- 10 kJ is equal to around 2.4 kcal.
Micronutrients, alcohol and fiber provide the body with various amounts of energy:
- Carbohydrates: 4 kcal per gram (17 kJ per gram)
- Proteins: 4 kcal per gram (17 kJ per gram)
- Fats: 9 kcal per gram (38 kJ per gram)
- Alcohol: 7 kcal per gram (29 kJ per gram)
- Fiber: 2 kcal per gram (8 kJ per gram)
These are averages. The amount of energy your body can actually use depends on various factors.