I was wondering, do you think it is just the increased calories on the carb up days, the carbs alone, or both that "rev" the metabolism?

It seems like if you can avoid eating too many carbs on high cal days, that you should do it (if I stray very much above 70 I start to get carb symptoms). But then on the other hand, it is probably a LOT harder to eat all the food you need to eat on a carb up day if you're carb levels are low.

Still, I wonder... is it the carbs or the calories?