Celebrity endorsements for food and drink products from A-list stars including Britney Spears, Justin Timberlake, will.i.am, Christina Aguilera and Mariah Carey, overwhelmingly plug brands that are nutrient poor and high in sugar, according to researchers investigating the impact of advertising. They say that the use of celebrities to market products to young people is contributing to childhood obesity.

“Because of [the US]’s childhood and teenage obesity public health crises, it is important to raise awareness about how companies are using celebrities popular with these audiences to market their unhealthy products,” said Dr Marie Bragg, a psychologist at New York University Langone medical centre who carried out the study with colleagues. “Research has already shown that food advertising leads to overeating and the food industry spends $1.8bn (£1.2bn) per year marketing to youth alone.”

The team looked at every endorsement collected in a US advertising industry database between 2000 and 2014. They identified 65 celebrities who had directly or indirectly advertised 57 different brands of food and beverage owned by 38 companies. The researchers defined endorsements not only as appearances in radio, television and magazine ads, but also as a celebrity’s participation in a concert sponsored by a product.

To score nutrient values for the products, the scientists used a set of indicators that also form a standard for child-targeted UK food marketing research. More than 80% of the selected 26 food products scored as nutrient poor. Of 69 beverages endorsed, 71% were sugar-sweetened.

The biggest category of endorsements overall was for full-calorie soft drinks. Pepsi, for instance, was endorsed by, among many others, Beyonce, Britney Spears, Christine Aguilera, Enrique Iglesias, Justin Timberlake, Katy Perry, Mariah Carey, Calvin Harris, Nicki Minaj, One Direction, Shakira and will.i.am. Christine Aguilera, Calvin Harris and will.i.am also endorsed Coca-Cola. Taylor Swift was the only name from the sample associated with Diet Coke.

“There were no endorsements for fruits, vegetables, or whole grains but one celebrity endorsed Wonderful Pistachio, which was the only food product with a healthy score,” the researchers wrote in the paper published in the journal Pediatrics.

One in three children in Europe – where some of the products endorsed are also sold – between the ages of six and nine are either overweight or obese, according to a study published last week. While research predicted that around a fifth of all adults around the world will be obese by 2025, with potentially disastrous health consequences. Nutrition experts have repeatedly warned about the impact of fast foods, sweets and sugared drinks on public health.

The American Beverage Association, which speaks for the US soft drinks industry, did not respond to a request for comment. But in May the association said it had responded to a 2010 challenge by the first lady, Michelle Obama, by putting prominent and clear calorie labels on bottles. “We believe people should have clear and understandable nutrition facts about foods and beverages so that they can make informed choices that are right for themselves and their families,” the statement said.

Dr Bragg said she hoped that the companies would take a closer look at the kinds of products they are promoting and shift some of the endorsements to include healthier beverages and foods. “That would really help young people and parents in their efforts to make healthy beverage choices. Most of these companies do have healthier alternatives but what we saw in our study was that the endorsements featured sugary beverages and unhealthy foods, with very little promotion of healthy products.”

She also hoped that her study would provoke more discussion among music industry performers, she said. “I imagine it’s hard to turn down a multimillion dollar endorsement offer, so perhaps they could play an active role in requiring their endorsements to be low-calorie beverages or nutrient-rich foods. I imagine companies that are eager to sign these stars might be responsive to those kinds of requests.”

Food and drinks companies in the US have voluntarily pledged not to target children under 12. “Given the heavy targeting of adolescents and the amount of money they spend on foods and beverages, voluntary food marketing pledges should expand to include teens,” Dr Bragg said.

The research follows an earlier study by the same group from 2013 which found that foods and drinks promoted by celebrity athletes were also overwhelmingly unhealthy.