https://en.wikipedia.org/wiki/Calorie
"In a nutritional context, the kilojoule (kJ) is the SI unit of food energy, although the kilocalorie is still in common use.[15] The word calorie is popularly used with the number of kilocalories of nutritional energy measured. To avoid confusion, it is sometimes written Calorie (with a capital "C") to make the distinction, although this is not widely understood (in part because capitalization contravenes the SI rule that the initial letter of a unit name or its derivative shall be lower case in English)."
Japan uses the "proper" term on their nutritional labeling.