“Encourage restaurants and caterers to donate leftovers. Ask if they can donate leftovers to food banks.”

I don’t think you understand how a food bank works, or a restaurant. Food banks generally don’t handle prepared food because they have no way to store it or transport it. The fact that it’s a “bank” means they need food products that are packaged and will keep since they might not go out the door right away. The vast number of donations to food banks come from supermarkets and individuals, not restaurants. Restaurants packaging leftover meals to give them away would be a huge pain in the ass for them, and is something the health department will take a dim view of. Just because people are poor doesn’t mean you can sling any kind of leftover food at them.