I'm not sure if you can answer this, but why is it that people who have anorexia [nervosa] are usually easier to spot than people who have bulimia [nervosa]?
-- Karen (last name withheld)
I think what you are referring to, Karen, are some of the physical symptoms of these two particular eating disorders.
Anorexia nervosa is accompanied by extreme -- and sometimes rapid -- weight loss.
In turn, faces can become gaunt, hair can start thinning, and clavicles and ribs can become more visible. To the naked eye, anorexia nervosa is certainly more visible.
One reason why people living with bulimia nervosa can live with it for so long without physical manifestations is because purging -- whether through self-induced vomiting or excessive consumption of laxatives -- does not eliminate all consumed calories.
The latest studies emerging from the University of Pittsburgh -- conducted in a laboratory setting, where researchers first calculated the amount of calories in patients' binges and then analyzed what was regurgitated for caloric values -- have determined that approximately half the calories in a binge are retained by the body.
Keeping in mind that some binges can consist of 3,000 to 5,000 calories in one sitting, it is very feasible that, even after purging, someone can provide their body with a day's worth -- or more -- of calories.
This is very much in contrast with an anorexia nervosa picture where caloric intake is often in the low three digits.