Jag isn't even used over here but I still knew what was meant. I think the word I'd likely have used would be 'bender' or perhaps even 'fest' it would have been something that similarly conveyed an over-indulgent detour though.
'Krispy Kreme' is the stranger bit to grasp here for me as it seems like a proprietary name for a 'ring doughnut'. I doubt what we'd call a doughnut quite hits the same spot as a Krispy Kreme though, as the doughnuts you get from grocery stores here are either too dry (stale) or too stodgy or more commonly both those things.
Doughnuts are best served fresh for sure.