If you have allergies or certain dietary restrictions, that is something you’ll need to be proactive with. With as many unique diets and needs as there are, we are unable to accommodate everyone. However, we can talk to you about certain locations that might be a little easier for you to work around your diet (maybe choosing a location where you’ll be shopping for your own groceries would be a better fit than a host family situation).
In any case, if you have certain dietary needs, plan on adding more to your spending budget so you can purchase snacks and meals that fit your diet better than what the local cuisine may provide.
Additionally, you may find this blog post about eating vegan, vegetarian, and/or with dietary restrictions while traveling helpful.