Perhaps he is going through a growth spurt??
At times like this when you are certain he is still hungry, it's ok to increase solids but what he really needs to fill him up is milk. So be careful that you are not replacing milk with solids. The milk feeds will sustain him longer so if anything try to get more milk into him.
Otherwise, if it continues longer than a few days and is not a growth spurt, you might want to look into your routine. There could be other reasons for his waking, and if it actually isn't hunger then you don't want to be reinforcing a feeding habit by continuing to feed, kwim? You can also try posting on the NWings board, or the EASY board if you think it is a routine issue.
