Whenever I visited France to stay with pen friends, their standard breakfast was cake (the sort made in loaf tins rather than big and round with icing).
They were most surprised when I was surprised about eating cake for breakfast - and when I said that we would more normally have it at tea time (they would apparently have gateaux or patisserie then!)
Think about it - it is a good breakfast food if you get a decent one. It's got eggs in (good protein), flour (carbs), sugar for energy, fat (everybody needs a bit), carrots or cocoa are both good for you...
I often make banana-ies (like brownies but with bananas in, instead of cocoa), with spelt flour and they are good breakfast cakes. Sometimes they have nuts or choc chips in. But lots of bananas, eggs, spelt for slow release carbs, all sorts of stuff.
And the next recipe i'm about to try is healthy brownies with apple sauce instead of most of the fat and sugar, which also sound ideal for breakfast.
I certainly don't think they are any less healthy than toast and jam, or cereal. A healthy version of the traditional english breakfast is probably the best start to the day though!