Bulimia is the binge-purge syndrome in which people eat too much and then vomit, overexercise, and/or starve.The purging, especially, messes with electrolyte balance, esophagus and digestive system functioning, metabolism and heart health. Most of the food in the binge gets absorbed anyway, so there's really no fooling mother nature here.
For starters, to overanalyze where these urges originated, how they developed and how to become another kind of person proves too hard. Better is to look at the obsessive nature of the behavior and attack it behaviorally. Learn to wait out the urge to keep eating or to purge, first a little while and then gradually longer. Distract yourself onto anything non-destructive, and congratulate yourself anytime you didn't give in to the eating disorder. Learn from each failure and each success (time when you beat the temptation). What were you thinking? What were you feeling? Where did things start going wrong? What could you have done instead? Note it for the next time.
Once you can get through a day, then several days, then a week, then several weeks, etc,. the urges dissipate greatly, giving you time to learn to eat properly. Eating properly includes eating anything, moderating portions, and staying within a sensible weight range by eating a little more or a little less for a week when on the edge of your weight range. Once eating is less of an issue, you can learn to think and feel fully without fear, so you won't need to numb yourself with addictive behavior or distract yourself from real issues by creating a health disaster.
Remember, bulimia destroys health, appearance (ultimately), metabolism (making weight gain easier in the future) and social interaction; wastes time, and money; and leaves you with a feeling a shame. You can overcome it gradually with the help of a good therapist, eating coach, and support group.