You probably need to prepare for the 10 days achievements. This one requires you to avoid fishing altogether for 10 days. That means you will need to rely on the food sources on the land, such as Boar, Crab, Snake, Coconuts and fruits such as the kuwawa fruit. If you're starting a new game, you will have some emergency rations in your life raft satchel, which will hydrate you as well as satiate you about half your meter.
Note that certain foods, like Coconuts, will make you sick if you only eat it without any other food source, so make sure to get a little bit of everything.