Ask Mary

Food begins to be digested immediately upon entering the mouth, and vomiting does not expel all of the stomach contents.  When the stomach suddenly contracts to vomit, around 50% of its contents are pushed further down into the intestine where they will be digested and absorbed.  An often quoted 1993 study published in the American Journal of Psychiatry concluded that bulimic patients retain approximately 1150 calories after vomiting, regardless of whether they binged on a large or small meal.