days & nights switched? (XP)

I'm starting to suspect that DS is getting the bulk of his calories during our nighttime feeds.  He "eats" (snacks?) every 1.5 - 2 hrs during the day, but lots of shallow sucking and not much swallowing that I can hear, but overnight he's doing deep, drawing sucks and swallows (waking to eat every 1.5 - 3.5 hrs).  His diapers are super full overnight and until about midday and minimally wet the rest of the day.  He is gaining great so I'm not worried that he isn't getting enough overall, but ideally I'd like him to consume more during the day and sleep more at night. 

Has anyone dealt with this or have suggestions on how I might get him to switch it around?  I offer the boob whenever he might want it during the day, so I don't think that's the answer, but I don't know what else to do.

Thanks!