I have noticed that when I eat right before bed (and bolus correctly), I almost always wake up with high BG. I suspect that the role of active insulin changes during sleep, from glucose metabolism to one of the functions listed below (via www.diabetesinformationhub.com).
"Functions of Insulin
In addition to its role of regulating glucose metabolism, insulin also
Increases amino acid transport into cells
Altering the cell content of numerous mRNAs
I recall from biology courses that a few of these functions happen primarily during sleep, so I think that as a rule of thumb, it is best to hit the pillow once the bulk of any active insulin has finished its work.
All opinions, thoughts, etc. will be greatly appreciated,
Brandon (T1 dx 07/21/12 - Minimed 523 no CGM)