When Debbie St. Onge of Hyde Park, New York, was shopping with her 2-year-old son, she looked back from the groceries she was buying to find chocolate smeared all over her son’s face.

“I was busy checking out a pile of groceries and didn't notice that he had acquired and consumed a chocolate bar from the checkout display,” St. Onge told Healthline.

For many parents, this story is all too familiar. But for stores it is a sign that their checkout displays work well as encouragements for last-minute impulse buys.

A new report released by the Center for Science in the Public Interest (CSPI) takes aim at junk food in the checkout aisles.

By calling on stores to take down the wall of candy and other snacks facing shoppers at the end of their trip, the non-profit advocacy organization hopes to reduce unplanned purchases of high-caloric snacks — a hot topic in a country with high rates of obesity, diabetes, and other food-related illnesses.

Read More: We Can’t Resist Junk Food, Even When Our Health Depends on It »

Resisting the Nag Factor

According to the report, in 2012 companies sold $11 billion of potato chips, tortilla chips, pretzels, and cookies. Sales of candy are even larger, at $34 billion a year.

Checkout sales alone of food, drinks, and other items net companies about $5.5 billion each year. And although junk food is found throughout most stores, CSPI has chosen to focus on those last-minute impulse buys.

Many parents are aware of the challenges of shopping with children, but checkout aisles offer the perfect combination of marketing factors.

“It’s the bane of my shopping existence for myself and my kids,” Sarah Moloney, a mother from Owen Sound, Ontario, Canada, told Healthline. “It’s that last-ditch attempt to leave the store with healthy items intact and — bam! — don't forget your crap impulse buys before you leave.”

Even when children don’t take matters into their own hands, the overwhelming amount of junk food awaiting them at the checkout can stir up what some researchers call the “nag factor” — the tendency of children to respond to marketing by asking their parents to buy those products.

Read More: Junk Food and Diabetes »

Checkout Is Marketing Dream

Placement is key, with candy and other snacks at eye level and within easy reach — something that is not unique to the checkout aisle.

Some research has found that just viewing food can encourage impulse buying.

But there’s also one other factor that most parents are familiar with, and that is fatigue.

This extends beyond just the physical. Some research has found that willpower is like a muscle that can be tired out from making too many decisions.

The typical supermarket contains 30,000 to 50,000 products, according to the CSPI report. So by the time you hit the checkout area your willpower is sapped, making you more prone to poor snack choices.

“You’ve already been through the store with [your children], so of course you’re kind of worn out, they’re a little bit worn out,” Bettina Siegel, a writer and food policy commenter, said in an interview with Healthline. “And you know that as you bring your cart to the checkout aisle that there’s going to be this almost inevitable conflict.”

Read More: The Effects of Fast Food on the Body »

CSPI Targets Checkout Junk Food

CSPI’s push for healthier checkouts includes encouraging food stores to eliminate the junk food at the cash register.

But the organization is also targeting non-food stores that stock candy and other less healthy snacks at the checkout.

“Companies like Bed Bath & Beyond need to recognize that they have their own role to play when it comes to preventing diabetes, obesity, and other diet-related health problems,” CSPI senior nutrition policy counsel Jessica Almy and lead author of the report, said in a press release. “Right now, they’re making those problems worse.”

For those who have grown accustomed to the walls of candy at the checkout, these changes may seem far-fetched.

But three major grocery chains in the United Kingdom have already eliminated candy from their checkouts.

Many parents won’t wait for stores to shape up, however.

An online request by Healthline for tips on steering clear of junk food at the checkout aisle came back with a flood of responses — from just saying no, to leaving the kids at home, to eating a meal right before shopping, to shopping only at health food stores that don’t sell junk food.

For some, this includes reminding children that even though they may ask for candy every time: “It’s my job as your parent to say no.”

Checkouts, though, are one small piece of a complex food ecosystem dominated by junk food, something that makes staying healthy as a family more difficult.

“It’s getting harder and harder for individuals, and certainly for parents, to stay on the path of healthful eating,” said Siegel, “because there are so many forces pushing us — quite intentionally and often beneath our conscious awareness — into making choices that don’t benefit us.”

Take the Challenge: Can Your Family Go Junk Food-Free? »