Quoted By:
If you want to be fit during your journey as a trainer you have to get a Pokemon that can help you with that. Being a trainer is hard because you are mostly on your own unless you are with a group. You better make sure you can cook well and can afford basic stuff for you and your Pokemon.
Trying to win the league against other trainers could lead into some bullshit battles because they can use the power of friendship or something to have stronger moves. You have to improvise your moves a lot in order to have a chance to win.