Hi @alancolyer,
New to ACF Pro is the JSON Sync(added in v5.1.5) feature that allows which detects changes to local JSON files and allows the user to update the corresponding field groups within the Database. This functionality is visible when viewing the field group admin page but only when ACF has detected there are field groups available for synchronizing.
You can also opt to do the importation of the fields using the PHP export facility that allows you to copy the export code to your theme files.
Calling an import function is not available at this time.
Please check out the resource page on the JSON sync feature here http://www.advancedcustomfields.com/resources/synchronized-json/
