It's funny, in North America, it's been accepted now for ages that you don't give babies solids before 6 months. So their babies don't suddenly "need" solids at 4 months!
I'm also trying to make it to 6 months, we're at 4.5m now I think. Luckily, DS2 is a really efficient feeder, but he does eat a lot, and is huge. He's still often having only one side, so I guess I can haul out the double-barrell treatment if he starts seeming more hungry.
I'm also not kicking him out of my bed until I'm ready to say "ok, no milk for you in the night".