By Jacqueline Howard, CNN

(CNN) -- Cheering on your favorite sports team and snacking on junk food often go hand in hand in the United States, but a new study sheds light on just how intertwined sports and unhealthy foods really are.

The study, published in the journal Pediatrics on Monday, reveals that 76% of food products shown in ads promoting a sports organization sponsorship are unhealthy and that 52.4% of beverages shown in sports sponsorship ads are sugar-sweetened.

Sponsorship was measured by instances in which the sports organization logo or name was shown with an official company name, product or logo in a commercial, banner ad, YouTube video or similar type of promotion.

The study focused on the top 10 sports organizations most frequently watched by children 2 to 17 years old, based on data from Nielsen ratings.

The researchers are concerned that such sponsorships could have a negative impact on children's food choices and diet, said Marie Bragg, first author of the study and assistant professor in the Department of Population Health at the NYU School of Medicine in New York.

Yet "there's a unique dynamic between the sports organizations and the food companies, and it's hard to know who should take more responsibility for the problem or if both organizations -- both sports organizations and food companies -- should take equal responsibility," she said. "I'm not totally sure what the answer is."

The Hershey Co. and PepsiCo were among the companies mentioned by name in the study. Hershey Co. said in a statement that it believes in "supporting organizations that enable athletes to showcase their talents and serve as role models."

"Sports are viewed together by multiple generations who understand that our products are a treat. In fact, candy makes up a very small amount of the average American's diet (about 2-3% of total caloric intake)," it said in response to the study. "We have a broad portfolio of brands that offer a variety of choices for consumers."

The company added that it participates in the Children's Food and Beverage Advertising Initiative, a voluntary program in which it has committed to not advertise its products to children under age 12.

In an emailed statement, PepsiCo said the company "has made strong global commitments on responsible advertising to children, and we have signed on to industry-led voluntary initiatives through several global, regional and national pledge programs. In the U.S., this includes the Children's Food and Beverage Advertising Initiative, which is administered by the Better Business Bureau."

A 'striking' finding

The researchers used 2015 data from Nielsen's television ratings to identify the 10 sports organizations with the most youth viewers. Then, they compiled a list of each organization's sponsors using publicly available information.

A research assistant, who was unaware of the purpose of the study, sorted all of the organizations' sponsors into categories, identifying which were food and beverage brands.

When it came to defining sponsorship, "it really has to be the partnership of either the logos or names showing up in the same commercial," Bragg said.

"Let's say a chip commercial showed up in between programming for the NFL. We would not count that unless in that chip commercial, it said 'official chip sponsor of the NFL' or if, during the commercial, it showed the chip logo next to the NFL logo," she said.

The researchers then "gathered nutrition information for all products shown in sponsorship advertisements by searching official food and nonalcoholic beverage companies' websites between January and March of 2016," they wrote. The nutrition information for each food product was evaluated using a profiling system called the Nutrient Profile Model in order to determine what could be defined as unhealthy.

The researchers also recorded the total number of food and beverage sponsorship commercials uploaded to YouTube from 2006 to 2016. More than 195 million YouTube views were associated with food and beverage sports sponsorship ads in that sample of commercials.

"This is the first study to our knowledge to really harness this new form of social media in getting a sense of how it's adding to the food advertising exposure picture," Bragg said.

The researchers found that the NFL had the most food and beverage sponsors, and the organization had the most youth viewership. The National Little League had the third-highest number of food and beverage sponsors.

"That was striking to me," Bragg said of National Little League.

"There could be the argument that it doesn't necessarily matter as much for childhood obesity if there are unhealthy products promoted where most of the viewers and sports organization players are adults, as opposed to Little League, where it's a lot of really young players and really young viewers," she said. "Still, they came in third place for the highest number of sports food sponsorships."

The study had some limitations, including that the researchers did not quantify sponsorship appearances within games on the sidelines or sponsorship announcements made during games. Also, the researchers did not determine what percentage of YouTube viewership data actually belonged to young people.

The study also does not explore whether the sponsorships actually influenced food preferences or behavior among children. More research is needed to determine whether the study findings have a real-world impact on diet, they said.

The American Beverage Association, which represents the beverage industry, has responded to the study in a written statement.

"As the authors of this study admit, the target audience for professional sports are not children but adults," the statement said.

"Nonetheless, America's beverage companies have taken actions to ensure parents have the support they want, including voluntarily implementing international advertising guidelines to not market to children under the age of 12, voluntarily pulling full-calorie beverages from K-12 schools and offering parents fact-based information and the wide variety of beverage options with and without sugar they need to make the right choices for themselves and their families," the statement said.

The message it could be sending to children

The researchers wrote in the study that poor diet is a significant driver of childhood obesity, and food marketing is one factor that contributes to poor diet among children.

"I think the study provides a good example of that," said Dr. David Ludwig, a professor at the Harvard T.H. Chan School of Public Health and co-director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital.

"Public health experts and pediatricians, when a child comes in for a visit, may warn against the risks of excessive weight, but for every positive message like that, 10 negative messages undermine the benefits -- negative messages in terms of food advertisements, which suffuse media today, broadcast media, the internet and athletic sponsorships, as this study shows," said Ludwig, who was not involved in the study.

"Food advertisers and athletic organizations have long had an unhealthy relationship, implying that if you're physically active, you can eat anything you want," he said. "The evidence is that very few children are realistically ever going to reach such high activity levels that they can outrun a bad diet."

Bragg also led a previous study on how popular music celebrities endorse mostly junk food. For that study, published in the journal Pediatrics in 2016, the researchers ranked a singer or group's popularity with teens and then analyzed the type of foods and drinks that the celebrities endorsed. A total of 163 celebrities were included in the study

The researchers found that among the beverages that the celebrities endorsed, 71% were sugar-sweetened drinks. Among the foods they endorsed, 80.8% were energy dense and nutrient poor.

In the United States, the prevalence of childhood obesity is about 17%, affecting 12.7 million children and teens, according to the Centers for Disease Control and Prevention. It's estimated that nearly one in five children and teens aged 6 to 19 are obese, but obesity is not just an American problem.

In the United Kingdom, obesity is estimated to affect about one in every five children ages 10 to 11, according to the National Health Service.

The World Health Organization has called childhood obesity one of the most serious health challenges of the 21st century. Globally, the number of overweight or obese infants and young children, up to 5 years old, climbed from 32 million to 41 million between 1990 and 2016, according to the WHO.

For people with young children, Ludwig said, monitoring their television viewing and setting a good example when it comes to food choices can help counteract the influence that advertising might have on their eating preferences and habits.

"Television has become a platform for programming children to want junk food," Ludwig said.

"So parents must protect the home environment," he said. "We may not be able to control the external environment in the ways that we like, but we can encourage healthful behaviors when our kids are at home."