that cake had beef gelatine in it.!!
You'll find the most interesting and disgusting stuff in generic stupidmarket foods. It really poses the "why?" question, because I don't remember putting gelatine in a cake once in my entire life. I guess it's all down to efficiency, the reigning utility for almost every business on earth. Make a buck as quickly as you can, and don't worry about whose toes you tread on.
Rock and roll to you for the switch! You're going to feel on top of the world in a couple of days! Keep your nutrition in check and you'll experience an abundance of energy previously kept under a lid.