My son went through an early waking stage around this age. What seemed to be consistent in the end was teething. It seemed strange at the time because all he wanted was milk when he woke but I think it was more because milk chills him out and comforts him. I mean, my son at that age would wake at 5, sometimes 4:30 then have a single nap for 45mins - 1hr and that was it. Now he wakes at 6 and sleeps for 1hr to 1hr 45! No change in his diet, just the teeth.