Your access token has a limit of 5000 requests per hour. The plugin will make an api request per set of 33 posts per feed along with 1 api request for the header if it's included. The plugin will also make an api request to retrieve comments if a post is opened in the lightbox and lightbox comments are enabled. The api request for the comments is only made if there are new comments to retrieve.
So for an average feed of about 20 posts with a header and comments enabled, you would have about 7 to 10 api requests depending on how often people make comments on your posts. If comments are disabled, only about 2-4 depending on how many times a visitor "loads more" posts.