In my experience, abstaining from food feels like an addiction. I start to enjoy the feeling of my stomach eating itself away, get a high from the self-control I'm exhibiting. If thinking about anorexia as a type of addiction for myself (I am sure that it is different for everyone though), the definition of an addiction is having a dependency on whatever is that addiction is for. Not being able to get through certain days, for example, without feeling you have abstained from eating is probably a red flag.

I think a lot of people "get away with" the dieting and fasting trend to lose weight because there is such a lack of education on the subject of real nutrition. For example, I know people that have done the paleo diet and make it an excuse to just eat bacon multiple times a day and gorge themselves on fruits. Too much of anything is simply too much, and too much of abstaining is no exception.

I think, often, when people say things like, "You are getting toooo thin," and such, even when the weight loss is done by association (not even on purpose) of eating well and staying active, people are either not used to seeing the person that way (humans aren't really the greatest about change a lot of times), or they are envious. I know that is a kind of a classic form of justification people use - "They're just jealous!" - but in a society where being thin is favored over being healthy (speaking for the US here), what's to be expected?

Even before I had problems with anorexia (I'm one of those that did not start for weight-loss intentions), I was told I ate like a bird and people were always trying to shove food down my throat. I think sometimes it is just people projecting what they want, or trying to justify their eating a piece of cake because it's more doable if someone is doing it with them! Haha. I definitely relate to that-!

I guess in summary, the line, I feel, is when one becomes dependent on fasting or dieting or abstaining, etc... when the quality of life is lessened because of the mental association rather than just the nutritional aspect. Unfortunately, I think a lot of people don't realize they are crossing the line, though of course people pull out of it. A lot of these diet crazes people go on are just phases or half-baked ideas I think, and they end up rubberbanding. Dieting is pointless! Lifestyle changes are necessary to really be healthy, and from that, the natural loss of weight, and to not just later go back to the same weight once you ultimately quit the diet.