going to have to disagree here. If being fed a healthy diet of crickets/earthworms/dubias and/or things of that nature you will have to feed the frog more than once a week. Only time I think otherwise is if you've fed a mouse/rat or other rodent etc. (which should not be often) in which case it would be best to wait a few days before feeding again
to answer the OP's question; it depends on the food you are feeding and how old/big the frog is. So: how old is the frog and what are you feeding it??