ok i thought bout this, in the water maps there should be those over sized fish! that goku catches in the water, they can kill you if u dont kill them theyd have some hp and there really fast, once you eat these fish you gain max hp, and about 150 ki for killing this fish, there would be only one once in a while like senso bean bags. if the fish kills you first you lose 150 ki!.. its a crazy idea i no but i think it should happen. or even if they dont give u ki.. just for some hp..