Yes, KILOCALORIE is a Scrabble word!

Letter values in Scrabble US: K 5, I 1, L 1, O 1, C 3, A 1, L 1, O 1, R 1, I 1, E 1.

Is it a valid word?

KILOCALORIE 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

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