This is not a request for advice on my own self-harm…
Bulimics usually keep their body from absorbing food by vomiting quickly after ingestion.
I have met, however, habitual, pathological users of laxatives.
How widespread is this? And wouldn’t it be fruitless since by the time food gets to the colon its “damage”–from the bulimic’s point of view–has been done?
In my experience, the use of laxatives is combined with one of the other eating disorders and isn’t used on it’s own. For instance, a bulimic will use laxatives in combination with purging just in case they ‘didn’t get it all’.
I think the mistake your making in your question is that eating disorders are rational. There is no rational thought in most cases of eating disorders. I have been both bulimic and anorexic and, while I told myself I needed to be thin to be pretty, it all came down to feelings of emptiness and needing to punish myself (psychology, yay!). It’s not the same for everyone, but generally ED’s are a symptom, not the problem itself.
It did occur to that the concept “useless” is a rational decision, and would be ruled out.
Also:
EDs: 
Eating Disorders.
Bulimia can involve binging and purging (through vomiting and/or laxatives and/or diuretics and/or enemas), and it can also involve excessive exercise.
As stated by others, bulimia isn’t always “rational”. But thinking about it, I could see how the use of laxatives, diuretics and enemas wouldn’t necessarily be used by a bulimic to decreased calorie absorption from food, but just to “get rid of” waste and to decrease your “weight”. If someone is obsessively weighing themselves frequently, they might use laxatives, diuretics or enemas to get the number on the scale as low as possible.
Speaking from past experience with dieting (sensible dieting, not an eating disorder), your body weight can easily go up or down several pounds per day just from normal urinating and defecating and changing water consumption. Using purgative methods would increase that - it’s “weight loss” that’s not really “weight loss” in that it’s not actual body fat, but just water weight or ahem solid waste matter.
Also: After you’ve done that to yourself, you feel “better” and may not purge later because you aren’t as hungry or don’t want to mess up the “good feeling”.
At least that’s how it was for me 32 lbs ago. I’m looking at that now, shaking my head, not believing I had “fat days” back then.
nothin
(bolding mine)
I think this is exactly right.
Also, the amount of laxatives and diuretics used is astonishingly high, for some. You may not be able to prevent all calories from counting, but you can cut it down a good bit. To a bulimic, every little bit ‘helps.’
The people I’ve known who abused laxatives weren’t bulimics: they were people who ate a fiber-less diet (baby food, shakes) but who still expected to defecate every day. The notion of “maybe you should eat an orange sometime” just didn’t register.
I agree. I didn’t use laxatives, but I did weigh myself before and after a purge. I can imagine one that uses laxatives does the same.
I don’t have an eating disorder (other than wanting to do more of it than is good for me), but have had a number of bouts of chronic diarrhea caused by lymphocytic colitis. My most recent bout lasted for months. It got to the point where a few hours after eating, I’d see in the toilet bowl actual snippets of what I’d last eaten. Really, really disgusting. I was starting to lose weight more rapidly than is healthy. Now, some of that might have been because of dehydration.
Now that I have found another gastroenterologist and the symptoms are being reduced, of course I’m starting to have to fight against overeating and weight gain again.
So, I think a continual misuse of laxatives, enemas, etc., could have such an effect.
