It definatly said it was assur to eat Pizza at Melava Malka and that one must eat Hemish Foods at Melava Malka
The book also spoke about the holiness or something like that of food like Gefilte Fish (Yuch) and Challah (Which I also cant stand) (I eat other kinds of bread when I have a choice like a Bagel or other breads with similar doughy insides).
I do know there have been “issuirim” about eating such things as sushi (because its not a “Jewish Food”) , I dont think this book mentioned eating sushi. I dont remember if he mentioned sushi at Melava Malka or not (He might have though and not in a positive light)
I found it like any other Halacha book , but written more in a spiritual way as opposed to straight halacha, I dont normally ask the rabbi what I see in a Halacha book , I dont ask a shaila on every single thing I see in a book. The rabbi is too busy for that