Purging and Calorie Absorption in Bulimic Patients and Normal Women

Abstract
Self-induced purging with laxatives is common among bulimic persons, who assume that purging reduces intestinal absorption of ingested calories. The efficacy of purging in reducing calorie absorption has never been studied, probably because the standard calorie balance procedure is expensive and time consuming. With a recently devised method, calorie absorption during a single day was measured to determine to what extent phenolphthalein or saline purge reduced calorie absorption. In 2 bulimic patients who regularly used laxatives for weight control and 5 normal young women, even extreme purging producing 4-6 l of diarrhea caused calorie absorption to decrease by only .apprx. 12% of calorie intake. The theoretical basis on which laxatives are taken for weight control is unsound.