It's lunch time, you joined a table with people, you are about to start eating, but just a moment before you do so, you want to wish everyone a good lunch.

If they were French you would say:

Bon Appetit

If they were Russian you would say:

приятного аппетита

And for Israelis it's:

בתאבון

But when I asked my friend how would he say it in English, he node his head.

Help me out, how to wish a good lunch in English?