Good one! Industry and consumption problem. Also I assume by candy bars you are referring to chocolate bars.
Industry: could offer chocolate bars in bulk packed sealed boxes or bags with waxy cardboard or paper packaging. This already exists for many independent products. However vendors and producers want to maximize profit on individual wrapped item, preying on weak wills around the cashiers.
Consumption: chocolate bars are bad for you. I'd tax sweets and sugary beverages a similar way we tax tobacco, cannabis and alcohol, so that it can give back to society's increased healthcare costs and dissuade excess consumption via increased prices. Currently producers like Mars, Mondelez and Hershey's get away scott free for poisoning the populace.