Canadian researchers set out to see which McDonald's Happy Meals that kids age six to 12 would choose when toys were included with healthier menu combinations, but not with standard offerings that are typically higher in fat and salt.
It turns out the children were three times more likely to opt for a healthier Happy Meal containing apple slices with caramel sauce and water instead of fries and pop when a toy came only with the more nutritional boxed meals.
"Overall, our findings suggest that toys have a strong influence on children's food choices," said Erin Hobin, a post-doctoral fellow in the school of public health at the University of Waterloo, who led the study published Sunday in the Canadian Journal of Public Health.
"And actually we also found that the toys have a stronger influence on boys than girls."
The study was conducted over a six-week period in August 2011 and involved more than 330 children attending YMCA summer day camps in the Waterloo region. For their lunch on the study day, each child was asked to pick a Happy Meal from an order form that showed photos of each meal combination and the toy, if included.
The kids were randomly assigned to one of two groups. Those in the study intervention group were offered the choice of four meals: two more nutritional combinations with a toy and two less healthy meals without a toy; those in the control group could pick one of the same four meals, but all included promotional toys.
"We wanted to try and make the study as naturalistic as possible, so that's why we chose McDonald's, because it is the most popular restaurant for children under the age of 13 in North America," Hobin said from Waterloo, Ont.
"That's also why we chose to use the actual toys that McDonald's were giving out the week of our study," she said, noting that they included tiny Smurf dolls related to a movie featuring the characters playing in theatres at the time.
The Happy Meals offered were hamburgers or a grilled chicken wrap with fries and a pop or either of the first two choices with apple slices in caramel dipping sauce and bottled water.
Hobin said the fact children in the intervention group were more likely to opt for the healthier meals when a toy was offered suggests that restricting promotional premiums could be one way to get kids to avoid eating less nutritional fast food.
"Currently, Canada has very few regulations restricting food marketing practices directed at children, despite the fact that government and non-government organizations have identified that reducing food marketing to children as a priority in Canada's childhood obesity strategy," she said.
"So our findings highlight a potentially effective policy measure for promoting healthier eating among kids when they're going to fast-food restaurants. And with the obesity epidemic and the increasing proportion of Canadians and Canadian children eating in fast-food restaurants, it might be something to consider."
Dr. Mark Tremblay, an obesity expert at Children's Hospital of Eastern Ontario, called the study's findings "rather compelling."
"One would hope that they (McDonald's and other fast-food chains) would look at this as an opportunity to contribute to the promotion of active healthy living in our children and take under advisement the findings that are in this report," said Tremblay, pointing out that one-quarter of Canadian kids are overweight or obese.
"So ideally, it would be great if voluntarily, if they use toys as part of their marketing of their product, that they would direct them towards their healthier alternatives and withhold them from the least healthy alternatives," he said from Ottawa.
In at statement, McDonald’s Canada said it is "proud of our Happy Meal program. The toy is a fun and engaging part of the Happy Meal experience for kids and parents alike, and we have no plans to change it."
The company said it does not agree the fast-food industry is responsible for high rates of obesity, as referenced in the report.
"We do, however, see ourselves as part of the overall solution," McDonald's Canada said. "Since this study was completed, our Happy Meal program has been reformulated to include an automatic offering of yogurt and the choice of apple slices or mini-sized French fries.
"All our Happy Meals are advertised with one per cent white milk, apple slices and yogurt, and meet the current Canadian Children’s Food and Beverage Advertising Initiative commitment."
But Tremblay said fast-food restaurants encouraging healthier eating through selective toy inclusion could be at least one small way of chipping away at the factors contributing to the high prevalence of obesity among both children and adults.
"Will this single-handedly solve the obesity epidemic? Almost certainly not. But is it a piece of the puzzle?
"I think that it's worth a conversation at least ... And this is just one organization. We need to remember that all of the fast-food spots do the same thing."
Hobin agreed there is no one-size-fits-all solution to solving the growing problem of childhood obesity.
"But our findings do suggest that limiting toys to healthier food options could potentially promote healthier eating among children."
She said research showed that in 2006, the top-10 U.S. fast-food chains spent almost $1 billion a year on child-directed marketing and toy premiums, a figure that is likely far higher in 2012.
"They're investing tons of money. They know toys have a strong influence on kids' food choices. Our study is supporting that," she said.
"Toys do influence kids' food choices, but they can also encourage healthy eating, not necessarily only for kids to order fries and the hamburger and pop."