Picante (my sister, currently taking an MN break) was given a tip to prevent early-waking in her nearly 3 YO DS, to limit the amount of carbs in his tea, and just stick to protein and veg/fruit instead. This goes against other things I've read of filling up their tummies overnight so they'll sleep til the morning. The idea is that carbs turn into sugar overnight and then they wake for more food (or something, not quite 100% sure of the science behind it!) DN slept until 7 4 nights running (almost unheard of) and I tried it with 14 MO DS and he slept until 7 too!! He didn't have his normal banana and only had a little bit of rice with his beef casserole, so I did extra steamed veg too. Previously both boys had been waking 5-6am most days.
I'm excited that we may have found a solution so I wanted to share it! I am going to try it again tonight, I just hope it wasn't a fluke. I can't imagine it will work for every child but it's worth a go and doesn't involve setting an alarm to wake your DC up at 4am!