[Warning (!): Mod is still under development, and is not intended for a long game] This mod adds hunger and ways to produce foods and drinks. From grown foods can be obtained effect capsules.
You cant refill the flask if you dont find a pure water source. If you find one just put in your hand a flask then left (or right i dosent remember clearly) click on the water patch and you can see the filling crafting.
If you add the mod to an existing save game there are no food or water on the map. The water is like the oil patch just blue. You can use the https://mods.factorio.com/mod/ChangeMapSettings
Mod to generate things