“On January 22, [personal trainer] Donna Harris received a cease-and-desist letter from the Mississippi Department of Health. Talking about healthy eating on Facebook and getting paid to do it, the department said, could trigger a $1,000 fine and up to six months in jail. In the eyes of the state, Harris was an unlicensed dietician — and apparently enough of a threat to public safety that she might need to be put behind bars.”