いただきます。

Itadakimasu.

Thank you for the meal. (before eating)

Word for word

“I humbly receive.”

Politeness: Neutral

Fixed expression that suits almost everyone, with no politeness marker to adjust.

When you would say it

Right before the first bite, said at home, at restaurants and by guests.

Worth knowing

Said to whoever made the food, and to the food itself. Hands together is customary.