S.J.
I have an almost 5 month old, and he displays this behavior when, a) teething and/or, b) hasn't pooped in a while and/or just doesn't feel like eating. Sometimes as soon as he poops, he is ready! I also notice my son will be super hungry one day and a few days later not so much. So, I would just continue to do what you are doing, then call the doc if wet diapers stop for a continued period.