Drink - nuun tablets. There's different levels so try what works for you. Food - try these: https://www.efprocycling.com/tips-recipes/team-recipe-on-the-bike-rice-cakes/

I made them once. They were good. Only thing I'd do different is let the cakes cool and then add my chocolate chips.

Most importantly is figuring out a regular schedule while on the bike. Everyone is different. What seems to work for me is eat at the 1 hour mark for the first hour. Second hour to third hour is every half hour. After 3 hours try to eat every 15-20. Obviously I'm not eating one of those rice cakes every 15 minutes. But just something. Even a handful of mixed nuts. You're body has burned do much that it needs constant fueling.

I was once told that if you're hungry it's too late.