The prayer that most people in the United States say before eating their food is the prayer "Grace"
The prayer before eating usually goes like this.
Bless us oh Lord for these thy gifts that we're about to receive from thy bounty through Christ our Lord, Amen or it can also be Bless us oh Lord for the food we are about to eat or receive from thy bounty through Christ our Lord, Amen.
Some people also say “Good bread, good meat, thank the lord, LET'S EAT.”
I never say any prayer myself because I'm not religious however some people are and that's okay.