You may be able to ration out the same meal for longer if you give it to her in parts. It'll make her less likely to be ravenous if she eats constantly. Get her into a schedule.

[Jotaro frowns and crosses his arms, mulling the situation over.] It is rough when you first start out but there are lots facilities that help new Trainers. Your money should get you at least to a Pokemon Centre where it's free accommodation and food. And the people in Cherrygrove's PokeMart often give out free samples. Then there's berries and the like you can find in the wild. Almost everything is safe in this world, you should have no problem foraging.

Is Mitzi any good for battling yet?