Almost one million Australians are suffering from an eating disorder, costing the nation a staggering $69.7 billion this year, new research shows.

The Paying the Price report, to be launched by the Butterfly Foundation on Tuesday, covers the prevalence and social and economic costs of eating disorders in Australia.

"Until now, we had no idea that the socioeconomic impact of eating disorders was comparable to around two per cent of Australia's GDP," said CEO of the Butterfly Foundation Christine Morgan.

The landmark report estimates there are 913,986 Australians with an eating disorder, with Deloitte Access Economics putting the total social and economic cost at $69.7 billion this year.

The report suggests mortality rates are almost twice as high for people with eating disorders than in the general population.