IF you find a water pump in a town just spam it until your water is full, it goes up to a value of 5000 but you spawn in with like 400, and food goes up to 20k.
If you find a water pump you won't have to worry about hydration at all, on the wiki its been calculated you could sprint for 72 minutes before needing to drink again.
As for food you just need to eat literally everything you find. You're stomach is endless in 0.63, your food value starts at like 500 and it goes up to 20000 as previously mentioned. Also you can even eat raw meat and drink from ponds without infection as its not in the game right now so thats a plus