I don't know about y'all but I have a profound weakness for Duncan Hines yellow cake and chocolate frosting. Growing up my Mom would make any cake we wanted for our birthday and that's all I ever wanted. To this day that's my only request -- guess I programmed myself through years of repetition.
Anyway, my wife made me that particular cake for Father's Day. Fortunately, she gave away a lot of it, but I was still able to pound a large piece every evening. That's an extra 400-500 calories a day, folks. Not smart.
So, my main point is that you shouldn't be afraid to throw away leftovers, especially when they are as dangerous to your diet as cake. You make the cake, have a big piece, then bring the rest to work or just throw it in the trash. You'll thank yourself later.