Please help me hide my food problems

I have an irrational fear of anything with added sugar, gluten, dairy, corn, any kind of gain(rice quinoa ect), legumes(peanuts, beans ect) or any thing like dyes or fake sugar. It all started when I did this diet called whole 30 about 5 months ago. It was great but you are supposed to slowly add stuff back in after 30 days but I just started eating all my normal stuff right away. Coincidentally I got the flu and so I return to my diet of mostly nuts fruit and eggs. Then I went and traveled with my friends to Costa Rica over Thanksgiving break and not wanting to be difficult I ate whatever they ate and got strep throat. Once I got home I was so relieved to go back to eating fruit and nuts again. But now I’m about to start nannying for family friends in another country and I don’t want to offend them when I can’t eat anything they make. My parents are going to stay there with me for 2 weeks to get me settled and my mother will absolutely kill me if she notices I’m not eating the food they make me and I’m just so stressed. I need ways to hide the fact that I’m not eating. No I can’t just tell her I have a problem she won’t care and my poor parents already spend so much on me for doctors bills this is the last thing they need.