In the UK, a number of supermarkets electively decided to stop the sale of impulse buy small pack checkout aisle junk food. Researchers curious about the impact had a peek at their sales data.
What they found was encouraging and they detailed their findings in their article Supermarket policies on less-healthy food at checkouts: Natural experimental evaluation using interrupted time series analyses of purchases. Plainly put, when compared with purchases from supermarkets still selling checkout aisle small pack junk, shoppers purchased 16% less small pack junk food from supermarkets that didn't offer checkout aisle junk food temptations.
Given the ubiquity of junk food in checkout aisles, and here I'm not just talking about the supermarket, but pretty much any and every checkout aisle, cleaning them up is a very real target in improving our food environment. And before you say it can't be done, it's been done with tobacco's "Power Walls" (but some irony here in that at least some of the new walls hiding cigarettes are being used to advertise junk food)