Answer by Professional Japanese Teacher
Thank you for the food.
“いただきます itakakimasu” is the humble form of “もらいます、食べます moraimasu, tabemasu” (to receive, to eat).
The direct translation is “I humbly receive it”. The origin of this expression is unclear but there are two main theories.
Some say it is an expression used when eating food offered before the gods in Shintoism. Others say it shows a sense of gratitude toward life forms that were killed as food for humans as taught in Buddhism.
Japanese children are taught from young to say this phrase before mealtimes. If they start eating without saying this phrase, they will be scolded by their parents for having poor manners.
At school, they are taught that this is an expression to give thanks to the meat, fish, eggs, and plants that will nourish and sustain their lives, as well as to give thanks to their parents, farmers and other people who work hard to provide and serve food on the table.
There is no equivalent expression in English and you may think of this as a way to say prayers before eating. I am sure that the inn staff would be very pleased if you say “itadakimasu” to her.