Itadakimasu: A Word You Say to the Food, Not the Cook
So the literal shape of “itadakimasu” is not “thank you.” It is closer to: “I humbly receive.”
And the thing being received is the food. Not the labor of the cook — that has its own phrase, said afterward, to the person. “Itadakimasu,” said before, with the eyes on the plate, is addressed downward and outward, to what is about to become part of you.