Yes, FOOD is a Scrabble word!

Letter values in Scrabble US: F 4, O 1, O 1, D 2.

Is it a valid word?

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

any substance that can be metabolized by an animal to give energy and build tissue
any solid substance (as opposed to liquid) that is used as a source of nourishment
anything that provides mental stimulus for thinking

Also: solid food, food for thought, intellectual nourishment.