Eating disorder behaviours such as purging, fasting and using pills to lose or control weight seems to be declining for most youth, yet are on the rise for those who are gay, lesbian and bisexual.

The findings are from a new study by researchers at the University of B.C., who analyzed data from U.S. youth aged 12 to 18 from 1999 to 2013.

The study, which was published online in the International Journal of Eating Disorders, found that gay boys were five times more likely to use diet pills compared to their heterosexual counterparts.

Gap between lesbian, bisexual and straight girls

The study also found the gap in the rate of disordered eating behaviours increased between lesbian and bisexual girls and their straight peers over the 14-year period.

Ryan Watson is the lead author of the study and a postdoctoral research fellow at UBC’s Stigma and Resilience Among Vulnerable Youth Centre (Gavin Fisher/CBC)

"The gap is really widening for lesbian and bisexual girls where it's not for boys who are gay or bisexual, and so really [there are] some differences here within sexual orientation subgroups that are pretty alarming," said Ryan Watson, the lead author of the study and a postdoctoral research fellow at UBC's Stigma and Resilience Among Vulnerable Youth Centre.

The research found that one-third of the bisexual girls reported purging (self-induced vomiting), which stayed roughly the same from 1999 to 2013. That rate increased over the same period for lesbian girls, and decreased for heterosexual girls from eight per cent to five per cent over the same period.

Watson and his fellow researchers analyzed data gathered from surveys administered at public high schools in Massachusetts every two years between 1999 and 2013.

B.C. data shows same trend, researcher says

Though they used U.S. data for the study, Watson said he and his fellow researchers will soon be publishing a paper using provincial data from the B.C. Adolescent Health Survey, which gathered information from about 30,000 youth.

"We're looking at the same questions with very similar outcomes about binge eating and fasting to lose weight, and we see the exact same patterns here in B.C.," Watson said.

Watson said his research does not provide an answer to why these rates of disordered eating are so different between heterosexual and sexual minority youth.

However, he said there is research suggesting that interventions and other programs to promote healthy eating are not reaching lesbian, gay and bisexual youth in the same way they are reaching straight youth.

Watson said the results of these studies could have implications for how these programs are planned and created in the future.

"I'd want parents, schools and clinicians to know there are these big disparities for this population," he said.

"We need to know it's more nuanced than just LGB(TQ) people have higher rates of disordered eating, but you need to consider the nuanced factor and see that lesbians and bisexuals actually may need to be approached differently."

With files from CBC's On the Coast

To hear the full interview listen to the audio labelled: Eating disorder behaviours on the rise for gay, lesbian, bisexual youth, UBC study finds