Taste different

A few minutes ago my son asked me if I could make him some French fries for him. I was in a hurry to make them for him and while I was cooking them he was eating crackers. He said he wanted to eat while waiting for the fries. When the fries were ready for him to eat he said that he doesn’t like the taste of the fries. I asked why and he just said it taste different so he was only eating the buttermilk waffles his favorite. He likes eating grapes all the time but unfortunately the grapes that I bought from Wal-Mart he doesn’t like he said taste different too. I do not know what to feed for my son.