However, although a dossier has been handed over to Spain's prosecutor general, the paper reported that a legal debate is likely over whether any criminal offences had actually been committed.
The Spanish-language websites and blogs, mainly read by young women aged between 12 and 28, were unearthed by an inquiry led by the technology unit of the national police, the paper added.
Aimed at ''people who make anorexia or bulimia a lifestyle choice'', the sites include advice on how to hide extreme weight-loss methods from family and close friends, and rapid weight-loss regimes that could be dangerous, it said.
Police also discovered an organization which arranges competitions for those ''who can lose the most weight in a set time.''
According to ABC, many of these sites are actually run by people in Latin America, although some sites in Spain have already been shut down.
Four sites hosted by Microsoft were closed at the request of the Catalan Agency for Internet Virtue (IQUA), a web watchdog, last November.
And in early 2007 another site -- which was launching a competition for young girls who lost the most weight in 14 days -- was closed down after protests from the Madrid regional government and Spanish health authorities.