1. Binge Eating Disorder (maybe I take this personally since it's the problem that I have) - if the person with BED is medically overweight, I sometimes think that we tell ourselves the same things a lot of anorexics (especially b/p type) tell themselves: "Stop eating you fat pig!!!" The difference is, someone who is anorexic is told the exact opposite by the rest of the world, and someone who is overweight and has BED is told the exact same thing by the rest of the world. Yeah, if it was that easy, don't you think we'd DO it?! Telling someone with BED to just "stop eating junk" is about as effective as telling someone with AN to "just eat a sandwich" - yet both seem to be persistent as all get-out. [Sorry for this being more personal rant-ish than I meant it to - I have NOT slept well.]
2. Bulimia Nervosa, non-purging type - I knew someone in college who very obviously had this problem, but was able to deny it because to her, exercise wasn't "really" purging, so she couldn't "really" be bulimic and was therefore perfectly healthy despite binge eating, crying and saying, "I'm so bad!" and going off to the gym for 3-4 hours at a stretch. For that matter, I'm not sure how seriously people take a bulimic who doesn't actually vomit as opposed to purging with laxatives or diuretics.
3. ED-NOS in the form of "meeting all criteria for Anorexia Nervosa, except still has a BMI over 17.5 and/or still has regular menstrual periods." While I agree that "wanarexics" are incredibly annoying and wish they would go away, there are people out there who started severely restricting or engaging in similar behaviors when they were so overweight that it will take a long time to show up as a problem, people who are visibly and worryingly underweight long before their BMI goes anywhere near 17.5 (my husband is one of them - he looked like a starving stray cat - although a very cute one! *grin* - at a BMI of 22 or so, when we met), and people who are playing the "don't diagnose me!" game. The website AnorexicWeb talks about "borderline anorexia" or "anorexia-lite" - people (mainly women and teen girls) who evaluate their self-worth almost entirely based on their weight, tend to slightly under-feed themselves, and are terrified of becoming fat...but are also terrified of the *label* "Anorexia Nervosa" and consequently maintain a BMI slightly above 17.5. While someone who is playing the "anorexia-lite" numbers game may not be in the same medical danger as someone with full-fledged AN, I think there is enough commonality in the overall mindset that this particular form of ED-NOS really needs to be taken more seriously than most people seem willing to take it.
4. Anorexia Nervosa in anyone other than a well-off Caucasian female teen or 20something. It tends to go rather ignored in boys and men, in non-Caucasian women and girls, and especially in the elderly (though I think some research is finally starting to be done there).
I'm curious what the rest of the community thinks about this - does my perception of what is not "taken seriously" fit with your experiences, either as someone with an ED or as someone who knows more about them than the average random person on the street?