pro-ana
adj. Promoting or encouraging excessive thinness, extreme weight loss, or anorexia.
Also Seen As
Etymology
Examples
2006
The group dieting that is relatively ad hoc among friends and sorority sisters takes a more organized form on the Internet, where spring break has become a popular topic on Web sites and message boards maintained by devotees of a controversial underground movement known as "pro-ana," or pro-anorexia, who sometimes identify themselves in public by wearing red bracelets. There are hundreds of pro-ana Web sites promoting and supporting the "anorexic lifestyle," despite aggressive efforts to shut them down by eating-disorder activists.
—Alex Williams, “Before Spring Break, the Anorexic Challenge,” The New York Times, April 02, 2006
2006
Pick up any gossip magazine, and you'll find a pic-filled spread. "Stars: Are They Too Thin?" they ask as every pound of weight-gain is breathlessly heralded as "a return to curves." These pictures usually make their way onto pro-ana (that's anorexia-promoting) Web sites, where they're tagged as "thinspirations."
—Mark Ellwood, “Is thin in?,” New York Daily News, March 09, 2006
2001 (earliest)
Health experts are calling for a ban on "sick" websites that use skinny stars such as Posh Spice and Kate Moss to promote anorexia as an acceptable "lifestyle" choice.

The so-called Pro-Ana sites offer tips on achieving "beautifully emaciated bodies".
—“Anorexia web fear,” Scottish Daily Record, February 14, 2001
Notes
A similar adjective is pro-mia, which describes people or websites that promote or encourage bulimia.