Food allergies
Hi there
Sorry to hear that the airline knocked you back. It seems a bit strange that they have this kind of policy as they probably have staff that have allergies and don't realise it.
It depends on how bad your reaction to foods are, maybe they could just be intolerances and you could explain them as these. I speak from someone who has explained this on medical forms for airlines when applying and also worked as cabin crew.
I hope you find someway to work it out if it is your dream, try another airline they may view the situation differently.