The answer to that question deserves a bit more space than I could devote to it in comments, so I'll try and address it here. To begin with, there was nothing particularly special about that day; my process of repentance and God's grace in setting me free from this life-dominating sin had actually begun months earlier. For background info, here is my testimony of how God freed me.
To explain how and why the bulimia ended completely on May 10, 2004, I will try and sketch an outline of the events of the months leading up to that day - most of which I cover in my testimony. After the birth of my third child in the summer of 2003, I returned not only to my binge/purge habits in full force, but also to the Friday/Saturday night ritual of whiskey with my husband. He has never had a drinking problem; I've only had one as long as I've been drinking. I loved being buzzed. I enjoyed being drunk. It allowed me to escape from the reality of who I was - a backslidden, hypocritical professing Christian with an eating disorder- for a few hours at a time.
Then the next morning reality hit with a pounding headache, and I'd seek solace in food while my husband was at work. And on it went.
Somewhere between 2002-03, I tried several times to come back to God; to tell Him I loved Him and wanted to change. I'd always fail. I could never go more than a day or two at a time without bingeing and purging, and each weekend I'd convince myself that I could drink "moderately". Failure and shame were my constant companions. In late 2003, (November/December), I went to a local "Healing Room" (intercessory prayer room at a local charismatic church) and confessed these life-dominating sins to complete strangers. They prayed. I wept. God forgave. I went 8 days - the longest period in 16 years - without bingeing or purging. (Or drinking.) I felt a brand-new emotion: hope.
Some Friday night in December I got drunk and woke up Saturday with a hangover. I hated myself and thought God was angry or, at the very least disappointed in me, but I desperately wanted His love and to be forgiven. I drove back to the prayer room...where I was told (without my saying anything) that God wanted me to know He was not angry at me; He was not disappointed in me; and that He loved me so much.
Disclaimer: I am (now) a cessationist. I firmly and staunchly uphold the sufficiency of Scripture and do NOT believe in private revelation. If that word was a form of 'prophecy' in terms of 'speaking forth the Word', I don't know. Maybe they were guessing. I don't know that, either. All I know is that God hears the prayer of a righteous man (or woman), and these Christian ladies loved God and loved me. The other thing I know is that day in late December '03 marked the beginning of my true turn-around.
When I walked out into the parking lot, I felt clean, forgiven, and joyful. The phrase "Live up to what you've already attained" came to my heart, although I didn't then know where it was in the Bible. (It's Philippians 3:16 for those who are keeping track. Did I mention I am a cessationist?)
I never took a drink again after that day; all desire had left me. (Which isn't to say the thought or fleeting temptation never passed through my mind again; I simply mean it was much easier to resist). The bulimia, however, did not leave so quickly. I would go, on average, a week or so before I would give in to the urge - for whatever reason - to binge and purge again. However, even in my failure, I held out hope - if, after over a decade of purging several times per day I could make it a week, there MUST be hope I could leave it behnd permanently! There were many tearful prayers and much pleading with God from the floor of my bedroom...and I would get back up.
February 2004 was a rocky month. I remember slipping up more often, and thinking I was headed back into the eating disorder permanently. At my daughter's birthday party, and I gave in to the pepperoni pizza....and gave in to the temptation to purge. Odd how that stands out in my mind. There were several other incidents that month, and I recall nearly giving up. But I didn't....I went back to the prayer room and allowed others to intercede. Again.
To emphasize, nothing magical, mystical, ecstatic or otherwise dramatic ever happened in the prayer room. It was NOT a "deliverance" in the sense the word is commonly (and erroneously) used. Two or three other women were praying with and for me for healing as I repented, and then I'd go home...and stay in the Word. I lived on my knees, and studied my Bible every day. I learned what true biblical repentance was, and what grace looked like. Luke 15 reassured me of the Father's love, and Romans 2:4 cemented it for me. I felt Jesus closer than I ever had in my life, and I depended upon Him moment by moment. The caring, fellowship and intercession of the ladies at the Pentecostal church just helped all the more - Galatians 6:2 exhorts us to carry one another's burdens, and this is what these sisters did for me. I also credit them for helping me grow in intimacy with the Lord, doctrinal differences aside. Those matters seem to fade in importance when we gaze in adoration at our Savior.
February gave way to March, and with the coming of Spring new life seemed imminent. There must have been binge/purge episodes on occassion during those months, although honestly I can't remember anything in particular. I think I remember 2 weeks being a huge milestone of abstinence. Or was it 3? I don't remember. I remember really getting into Max Lucado's "Experiencing the Heart of Jesus", and rejoicing when everybody was out of the house and I had a few hours with Him alone (Jesus; not Max Lucado).
May came. The cravings were less and less frequent by now (I do believe bulimia alters your brain chemistry because of the endorphin rush of the binge; but it can be normalized once you go through "withdrawal" and don't give in to those urges). I had put on weight, but it didn't bother me. I truly had, for the first time in my Christian life, the joy of the Lord they sing about in songs. One afternoon, I must have been under stress or something....I did it. I gave in to my old habit, and stopped for a secretive "fix" at Honeydew Donuts. I think I bought half a dozen muffins - I remember at least one of them was pistachio. Pistachio muffins are good; nothing against them, but why are bakery muffins as big as your head? I couldn't eat a whole one now if you paid me.) Well, on May 10, 2004 I binged on a whole bunch of them, and after "getting rid" of them, I felt...
That was dumb. That was the most useless thing in the whole world. I didn't need to do that. That was a complete waste of time and money. I just really didn't need to do that - I don't HAVE to do that anymore. That verse about 'not being a slave to sin' - it's actually true. I don't feel enslaved to bingeing crazily on food and purging it anymore...it just doesn't do anything for me. I got no pleasure out of that whatsoever.
It was sheer habit, and that habit had been broken. I don't know if you've ever been a smoker, but I used to be one. Only problem was, every time I'd get pregnant, I'd have to quit (I may have been a lousy, crummy drunk bulimic smoker, but hey, at least I was a submissive wife). After Baby #2, almost a year after having weaned myself off the smokes, I go out on the deck and light one up - just because I "can", and I am far too Irish to give in without a fight.
Do you know what happens when you inhale, deeply, on a Marlboro after not having smoked in 11 months? You cough uncontrollably. Your eyes water and your head spins. You gag, cough some more, and nearly throw up. (But you keep working at it, because, after all, it's your habit and you're entitled to it, by golly!) Once the habit has been broken - physically and/or psychologically, it just doesn't bring you the same "pleasure", no matter how fleeting. It just leaves you vaguely disgusted, and rather bored with the whole thing.
So that was the last time I did it. I already knew it was a stupid and useless crutch, but this time, I knew it down to my core. All those verses about being a new creation didn't immediately come to mind, but my experience finally matched my theology - I simply was a new person in Christ, with new desires and habits. One of those new habits was immediately turning to Him when I felt stress, anger, sadness or rejection - which previously would have driven me to the food. I had practiced "putting off" the gluttony and "putting on" prayer and thanksgiving for so many months that by the time May 10 rolled around, it was second nature. When I failed by giving in to my "old" nature, I saw it for the useless stupidity it really was.
That may have been a bit longer than you wanted, but I hope it answered your question!