The food and beverage industry spends $2 billion US a year on ads targeted at teens featuring their favourite performers, a practice experts say will only end if youth and their parents themselves object.

In a study published in Monday's issue of the journal Pediatrics, researchers looked at the nutritional value of products endorsed by 65 entertainers between 2000 and 2014 in TV and radio commercials, magazine ads and YouTube videos.

Music celebrities were included based on the 2013 and 2014 Billboard Hot 100 Chart, whose popularity was verified by checking Teen Choice Award winners.

Marie Bragg of the department of population health at New York University School of Medicine and her colleagues found 81 per cent of 26 endorsed foods were unhealthy, according to the Nutrient Profile Index of energy density and nutrient levels.

Baauer, will.i.am, Justin Timberlake, Maroon 5 and Britney Spears had the most food and beverage endorsements, including fast food such as McDonald's, Chili's and A&W, as well as crackers from Nabisco, which sponsored a tour by boy band One Direction.

According to YouTube views of ads, Rihanna, Britney Spears and Beyoncé were the most popular celebrity endorsers in the study.

Ads part of YouTube traffic

PepsiCo, Coca-Cola and Red Bull were the companies with the most music celebrity endorsements, particularly for sugar-sweetened beverages.

"There were over 312 million YouTube views for these kinds of commercials between 2000 and 2014, so it is pretty striking that there is a lot of exposure to these kinds of ads and that most of the products are really unhealthy," said Bragg.

Right now nobody bats an eye at Beyoncé signing a $50M deal to sell liquid candy to kids - Dr. Yoni Freedhoff, who treats obesity

Few celebrities chose to endorse water or water filters. South Korean pop star Psy sponsored the healthiest product included in the study, Wonderful pistachios, in an ad played during the 2013 Super Bowl.

There were no ads for fruits, vegetables or whole grains.

Bragg suggested teens should not only be aware of the issue, but they should speak up about it, because if they complain about feeling manipulated the companies might change their tactics.

Dr. Yoni Freedhoff, who treats people with obesity-related illnesses, thinks media literacy alone won't suffice, given the scale of the health problems associated with obesity.

Shouldn't shilling hurt their brand?

"Right now nobody bats an eye at Beyoncé signing a $50-million deal to sell liquid candy to kids," said Freedhoff, an assistant professor of family medicine at the University of Ottawa who was not involved with the study.

Beyoncé performs during the 2013 Pepsi Super Bowl Halftime Show. She earns millions from ad deals that young viewers see via YouTube. (Mark Humphrey/Associated Press)

"I think that if that partnership affected her brand because the public was upset by it, we would see it stop."

Companies advertise because it works.

"Pitting my three kids against the Don Drapers of the advertising world with billion-dollar budgets and neuropsychologists and fMRI studies, that's not a fair fight," Freedhoff said, referring to the ad genius portrayed in TV series Mad Men.

Currently, advertising of tobacco products is banned to those 18 and under. He'd like to see a similar ban for sugar-sweetened beverages, for instance.

CBC News played some of the ads to a Grade 8 class in Toronto. The star power made the ads more memorable, some students said, but their enjoyment was tempered with a keen awareness of the "tricks they're trying to pull on us."

Changing how teens are preyed on by the food industry will likely require new regulations, Freedhoff said.

Prime Minister Justin Trudeau's mandate letter for health calls for restrictions on commercial marketing of unhealthy food and beverages to children, similar to rules in place in Quebec that ban ads directed at children under the age of 13. A spokeswoman for Health Canada said the age limit hasn't been determined yet.

Bragg said it will also be important for researchers to see how people respond to endorsements on social media.

The study was funded by the U.S. National Institutes of Health.