From what I've read, it's not the sugar you have to worry about, it is the
carb count instead, as piratesmate mentioned.
Also, you really can't just eat fiber and carbs/sugar. You NEED to eat a good protein with ANY carbs.
I've been on South Beach Diet for the past several weeks as I'm pre-diabetic. On Phase 1 I was losing weight just fine. But, it's not recommended to stay on Phase 1 for more than a couple weeks. as I've been slowly integrating into Phase 2 and slowly adding a miniscule amount of carbs back into my diet, I find I'm gaining the weight slowly back.

(I haven't even made it to Phase 3.)
I think I am going to have to change to a diabetic diet with the carb counting as I seem to be way to sensitive to carbs.
I never think of eating any foods just for "breakfast' or other foods should only be for lunch and dinner. When a person breaks their fast first thing in the morning after several hours of no eating, it is better to have a good protein and a (complex) carb. Not have something that is all sugar or carbs, the way america has been culturally trained to eat: waffles, pancakes, muffins, donuts.
Adult onset diabetes is one of the leading growing epidemics in AMERICA today vs. the rest of the world. Because children are now getting it, it is no longer referred to as "Adult onset diabetes." It's a
cultural thing, not genetic. Simplified, it's caused by HOW we eat, how we over-tax the pancreas by overloading our bodies with sugar, until the pancreas fails to produce insulin properly.
In some ways, diabetics are being forced to eat properly the way we should have been eating, all along.
Also, instead of quiche, look up frittata. It is the crustless version of quiches.