How Many Calories Lost Through Self-Induced Vomiting?

By December 6, 2012

I have an eating disorder, Anorexia – Binge/Purge subtype. In addition, I run a support website for people with all eating disorders. I have wondered myself and I’ve also gotten questions on my site about how many calories are actually absorbed vs. lost through self-induced vomiting. It’s my understanding that the absorption rate is different for different categories (carbs, protein) and, of course, the amount of time the food is left in your stomach before purging is a huge factor as well. A friend of mine gave me your site because she thought she had seen a detailed breakdown of this information maybe a month or 2 ago. I haven’t been able to find the information. Is this something you could help me with? I want to have the facts, however, with enough detail to demonstrate to these young girls that bulimia is NOT as effective means of losing weight as they think. If you could also give me the stats on laxatives (my understanding is you only lose 5% at a maximum). – K.L.

Dear K.L.,

This is a tricky one because, 1) it is virtually impossible to provide a breakdown of exactly how long each substrate (fat, carbs, protein) takes to breakdown after being in the stomach for “x” amount of time; 2) nor would I want to. That might promote ideas of how to get “better” at the practice. Suffice to say, absorption time is highly varied and may be different for each individual based on a number of factors.

The same is true for laxatives. Most of the weight that is lost with laxative use is fluid. So one feels lighter, but will easily replace those lost fluids the next time any food or fluid is put back into the body.

One study from the Annals of Internal Medicine reported that as little as 6% to as much as 12% of calories are actually spared from laxative use. That means it is an incredibly ineffective means of purging calories. Most individuals probably use laxatives for 3 main reasons:

1) Relief from the abdominal distention after a binge,

2) Temporary weight loss due to the large amount of watery diarrhea and/or

3) A false belief that laxatives purge all or most calories.

Upsetting the electrolyte balance either by self-induced vomiting or with laxatives wreaks havoc on the body and can be incredibly dangerous.

My suggestion is to emphasize the positive with those on your website. Spend more time talking about what it takes to eat with balance, variety and moderation than on how the body works as this inadvertently teaches others eating disorder “tricks”.

What skills can help when the urge to binge/purge is so strong? What helps you to be successful? What might help others?

Devoting time and energy to successful use of skills will go a long way toward lasting recovery.

Take care,

Juliet N. Zuercher, RD