I just posted this on the fitbit Challenge post but thought I'd post it here in case the info is helpful to someone:
If you're using a fitbit and want to sync with a tracking app, there's a 3rd party site I'd read about and have used successfully. The site is Fitmess - the url is
http://fitmess.herokuapp.com/
I had been using a food tracking site for a couple years before I got my fitbit and I didn't want to give up my history just to have something that automatically syncs. I'm not sure which food websites Fitmess supports. It automatically syncs periodically. I've had a couple times where the sync just didn't work but it's only been 2 or 3 total days since Feb 2015.
I think you have to have either a facebook or a google account to sign up.
The details of the food data don't transfer to the fitbit - just the total calories consumed that day. Same for fitbit data to the food app - just the total calories burned is what syncs.
Hope this helps someone!