There is probably an entry for business meal expenses in one of your Schedule Cs or K-1s in your Federal forms. (I believe this is a bug in TurboTax as a even a "$0" in a Sched C triggers the CO state to want a >$0 for the add back.)
Rather than trying to use the Easy Step, I found this by going to Forms and looking at each K-1 and Schedule C for "meals". (I don't know of a way to search the forms for "meals".) I had some issues so I deleted it from the forms page and then went back to the Easy Step for that Sched C and verified it to be empty.
You will likely need to delete the state data (File->Remove Colorado Data) and then go through the prepare state data again.
