My doctor says there is no need for a baby to be waking to eat after the age of 4 months. My baby girl (now 9 months) goes down at 7pm and wakes between 5am-6am now. She no longer wakes up multiple times a night since I stopped feeding her.
My parents (of three kids) recommended just letting them "cry it out" at night if they are waking without any reason. (ei Your child doesn't wake up with a dirty diaper). After about three nights (long and terrible for mom but wonderful after the three or four nights) they will no longer wake up and if they do they quickly self soothe themselves back to sleep.
It works and you will be such a happier mom with uninterrupted sleep!