Resynchronize FeedDemon with Google Reader

If FeedDemon isn't showing the same unread counts as Google Reader, you can force it to resynchronize with Google Reader by selecting Tools > Synchronization Options > Advanced > Resync Now.

This will mark all articles in synchronized folders as read in that copy of FeedDemon, and then download all unread articles from Google Reader and ensure that they're also marked unread in FeedDemon.