Which statement about calories is true?

The statement that a calorie is a unit of heat is true, as it is defined as the amount of heat energy required to raise the temperature of 1 gram of water by 1 degree Celsius. This aligns with the scientific foundation of calorimetry, which measures heat based on the caloric definition.

Additionally, the preferred unit in nutrition labels is the kilocalorie (kcal), often referred to simply as "Calorie" with a capital 'C'. One kilocalorie is equivalent to 1,000 small calories and is more practical for expressing the energy content of foods, which is why it is used in dietary contexts.

These two aspects combine to affirm that both statements about calories are accurate, making the compound statement true. Understanding the significance of these definitions is essential for interpreting nutritional information and managing dietary intake effectively.