Questions about the physiology of bulimia.

Let me preface this by saying that I would prefer not to discuss the psychology of bulimia in this particular thread - I have a very good knowledge of that particular aspect of the disease - I’m more interested in the physiology involved.

Most bulimics are considered normal weight or even slightly overweight, despite purging. Only patients who have a strong restrictive component to their disease (more associated with anorexia) tend to be underweight.

I personally, while not bulimic, am pregnant and barfing my damn face off. I’m still eating stuff, but it tends to come up fairly quickly; however, I’m still gaining a respectable amount of weight for a preggo lady at my stage.

So the question is this - when food is consumed, are the calories ‘taken up’ by the body almost instantaneously? Like the food hits your tummy and BLAMMO calories are absorbed? Or is it the case that bulimics binge so much food that it’s impossible to purge it all out leaving them with a calorie overload?


I’m not a doctor, but I am a diabetic, and I can tell you that some foods are taken up almost instantaneously - primarily simple sugars. If I eat a piece of candy that’s straight sugar (hard candies, jellybeans, that sort of thing), my blood sugar will go up within minutes of eating it. Sometimes it’s even absorbed through the gums - one trick they teach people around diabetics is that if they go so low that they can’t/won’t eat, you can try rubbing sugary stuff (honey, gels, etc) on their gums to get their glucose up.

Similarly, I’ve read that if you’re sick and throwing up, you can still get sugar into your bloodstream by eating candy, even if you immediately throw it back up. It absorbs quickly enough that you’ll get it even if you puke a minute or two later.

Fats/proteins are a different story - they take longer to digest, sometimes a matter of hours.