When it comes to tracking your energy intake or comparing the calorie content of different foods, the terms "calories" and "kcal" can often cause confusion. In this article, we will demystify these terms and explain their differences.
Main Differences: Large vs Small Calories
Calories are a measure of energy contained in foods and beverages, or the energy expended during physical activities. However, depending on where you live, energy can also be measured in kilocalories (kcal) or kilojoules (kJ).
A "large" calorie is indicated by an uppercase "C" and measures the amount of energy required to raise the temperature of 1 kg (2.2 pounds) of water by 1°C. On the other hand, a "small" calorie is indicated by a lowercase "c" and measures the amount of energy needed to raise the temperature of 1 gram (0.035 ounces) of water by 1°C.
To avoid confusion between large and small calories, the term "kilocalorie" (kcal) was created to refer to a large calorie. Today, the terms "calories" and "kcal" are used interchangeably, both representing the same amount of energy related to food and exercise. Therefore, there is no need for conversion as 1 kilocalorie equals 1 calorie in nutritional terms.
Calories can also be expressed as kilojoules (kJ), with 1 calorie (kcal) equaling 4.18 kJ or 4,184 joules (J). To convert from calories to kJ, simply multiply the calorie amount by 4.18. Conversely, to convert from kJ to calories, divide the kJ value by 4.18.
How are These Terms Used?
Food and beverage manufacturers are required to display nutrition facts labels on their products, providing information about energy content per serving or weight. The nutritional labeling system varies depending on the country. For example:
- United States and Canada: calories
- European Union (EU): kJ and kcal
- Australia and New Zealand: kJ or both kJ and kcal
- China: kJ
These labels help consumers make informed decisions about the healthfulness of packaged foods and beverages, including potential allergens or ingredients to avoid.
The calorie content of a food or beverage is determined by the amount of energy-supplying nutrients it contains, such as protein, carbohydrates, fats, and alcohol. Proteins and carbs provide approximately 4 calories (16.7 kJ) per gram, while fat provides 9 calories (37.6 kJ) per gram. Alcohol supplies 7 calories (29.3 kJ) per gram. However, it's important to note that manufacturers round the values to the nearest gram increment, so the total calories or kJ may slightly differ from the calculated amounts.
Foods with fiber, which is classified as a carbohydrate, may contain fewer calories than expected due to its indigestibility or poor digestion. Fiber contributes zero or few calories, depending on the type.
Summary
Calories and kcal are interchangeable terms in nutrition, representing the same amount of energy. They can also be expressed as kilojoules (kJ). Understanding these concepts is essential for effectively managing your energy intake and making informed dietary choices. Stay mindful of energy values and make wise decisions for your overall well-being.