One of my French exchanges ate next to nothing we fed her, we were really worried about her. Even when we asked her what she liked & cooked it, she just picked at a little. After she left, found waste paper basket in her room full of chocolate bar wrappers & crisp packets.
Tilly, if you want to PM me and tell me where you are, I can maybe help you find some! We don't do exchanges as such, but are always on the look out for host families, and often the teen kids of our families form a friendship with the furrin kids and then go and visit them etc.
We have a french student staying with us this year and from what I can gather it's about the cultueral experience for her and we are to carry on as normaln (having said that we'll be going out more as think it's only fair to show her local area and do some fun things).
On the first night I'm planning pizza, chips and salad as she will be late and want something quick and easy while trying to welcome her. If that's a reject will have some bread/ham, cheese and fruit on offer. Thought about roast the second day. Will ask if she will eat what I'm cooking for our main meal. If not, we always have various options in the freezer, meat pies, fish, sausages, veggie burgers. We always have veggies and salad, so if it turns out she won't eat what we're having it's no big deal to do a salad.