Babysitting

Looking for advice. I have a friend who asks me to babysit from time to time. Usually it’s at my house. I don’t mind feeding her child however her child is an EXTREMELY picky eater. As a result the child refuses to eat and I end up giving unhealthy snacks to compensate. Would I be wrong to tell her that she must provide food if she wants me to watch her child? I am just tired of wasting food whenever the child comes over because they refuse to eat what I provide. I also don’t want the child complaining they are hungry in my care. It’s also a tad annoying to me bc she’s very aware of her child’s eating habits but never plans ahead or packs food. She just leaves it up to me and I am left texting her asking what I should be providing. Don’t get me wrong she doesn’t ask often and I don’t mind doing a favor but at the same time I can’t help but be annoyed when it does happen.