Yes, CALORIES is a Scrabble word!

Letter values in Scrabble US: C 3, A 1, L 1, O 1, R 1, I 1, E 1, S 1.

Is it a valid word?

CALORIES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure; used by nutritionists to characterize the energy-producing potential in food
unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure

Also: kilogram calorie, large calorie, nutritionist's calorie, gram calorie, small calorie.