Left to do my own thing

So my sister emailed me today and asked me what i wanted to do about food while I'm in Melbourne with her. She said
"Do you just want to eat what we have for dinner or would you prefer to do yr own thing – I can get whatever u want in the shopping & you can sort yourself out.  Anyway whatever makes you feel most comfortable so have a think about it & let me know."

I dont know what to say ... 
I know what I want to do and what I should do.
I don't know if i will be able to sit down to a meal with them, what if i panic and they have pizza or something and i cant purge?!
I'm in 2 minds. 

Voice 1: Yes please leave me to my own, so i can eat my egg white for breakfast, my apple for lunch and my cup of tea for dinner, with the occasional binge and purge and lose more weight while I'm over there, so I can come home and people can say - wow have you lost weight, you look so good-


Voice 2: No please don't leave me to my own, otherwise I wont eat and I'm hoping that coming over to Melbourne will help me remember how I used to be cos I cant seem to remember what it was like to eat normal and feel normal when eating