Karkarmar: It was clear that shoppers who brought their own bags were more likely to replace nonorganic versions of goods like milk with organic versions. So one green action led to another. But those same people were also more likely to buy foods like ice cream, chips, candy bars, and cookies. They weren’t replacing other items with junk food, as they did with organic food. They were just adding it to their carts.
The full story is here, via Peter Metrinko.