My two were a nightmare for suddenly deciding they didn't like their food anymore, usually when I'd just stock piled as they'd been gobbling it up previously. The local animal shelter did very well out of it!
We gradually realised that fish is not of interest at all and they don't like anything in jelly but love cat food with gravy or sauce. And only chicken or turkey is of any interest.
It took well over a year to get to where we are now and they've been eating the food they get now for about a year.
So now I've said that, they'll probably go off everything I've just bulk ordered for them