Though it's been two years since the OP posted here, I feel an obligation to weigh in, and hope this will be read.
Lisa, you are clearly putting yourself under law. You have just the one area in your life where you let yourself really do what you want, you said -- and that's the cry of someone under law. That's where your guilt comes from, I'd say: you think that you shouldn't be letting yourself have your treats, either, because you don't feel free to be you.
Let me quote something:
"It is for freedom that Christ has set us free."
Freedom, not bondage. If you don't let yourself do what you really want, that means you're living under some set of rules you think you have to satisfy. That means you think that's it's rules that determine who you are. But that isn't freedom, it's bondage.
A simple step is to pick a place in your life where doing what you really want to wouldn't be wrong at all, but you have never felt right doing what you really want -- then do what you really want. It's a declaration that the rules don't own you, that you have what Jesus gave you: freedom.
Then pick another one. They can be simple. One, for me, was picking up other people's trash. I was taught that just wasn't done; it wasn't respectable to pick up trash, and other people were supposed to be responsible for their own. But I'd always felt that trash should be picked up, period, and one day I made myself throw out the rules and the respectability, and when I saw some trash, I picked it up. Wow, did I feel embarrassed, like all the people around were looking down on me! and depressed, because all the people I knew who thought it just wasn't done were going to look down on me.
But I knew one thing: God wouldn't look down on me. So it didn't matter what any people at all thought; I was His property, not theirs, so their opinion didn't matter.
It is indeed freedom that Christ freed us for. That led Paul to tell us something else, something very important to people who feel terrible because of rules:
"All things are lawful".
Paul didn't make any footnotes, any qualifications: all things meant all things, and still does. Why are all things lawful? Because Christ set us free from the law, by fulfilling it for us. We are free from the law -- set free, to be free. So eating everything you want is lawful -- the Apostle said so.
What it isn't is profitable. You know it isn't profitable. But you worry that you don't feel sorrow over it being a sin. Well, since all things are lawful, you don't have to worry about sin -- you just have to worry about whether things are profitable, by which Paul means beneficial. You know it isn't beneficial, and you have sorrow over that -- and that's all the sorrow God requires.
But it doesn't mean you deserve to be loved or forgiven. In fact, you don't deserve to be loved or to be forgiven -- none of us do! We are, in truth, more "crappy" in the eyes of God than we could ever imagine. We are like a rusty piece of metal stuck in a sewage ditch, worthless and getting more so, and there's not a single thing any of us can do to change that. But one day, along came a great man, a wealthy man, and he saw that crappy piece of metal, and for no reason in the metal he scooped it up, took it home, cleaned it off, and said, "I'm going to turn this into a treasure".
He didn't say, "I'm going to make it turn itself into a treasure". He didn't say, "What a treasure -- I'll take it home!" He knew it was a crappy piece of metal, and that if he left it there it would never be anything but a crappy piece of metal, but being who he was, he picked it up anyway, and set out to turn it into a treasure.
You're that piece of metal, and that great man is God. He didn't require you to clean yourself before He took you home. He didn't take you home and clean you and then require you to polish yourself to be in His home, he just took you home. And He didn't require you to turn yourself into a treasure -- He's going to do that.
You didn't deserve to be loved, but our gracious God loved you anytway. You don't deserve to be forgiven, but Jesus took care of that, and God forgave you anyway.
In Baptism He washed you. It doesn't matter that you had no clue what was going on; in the New Testament Paul baptized entire households based on the declaration of faith of the head of the household! Your parents' faith was sufficient -- and when God washed the crap off you the piece of metal, it was washed. It doesn't have to be washed again -- when He washes something, dirt doesn't stick. When He looks at you, all He sees is the piece of metal He washed, the one He picked up because He decided to love it.
Now, you think that should make you feel good about yourself, but you say it doesn't. Well, that's because you haven't surrendered. And you haven't surrendered because you haven't even allowed yourself to own yourself, which makes it a little difficult to surrender yourself to God. And that takes me back to not doing anything you really want: whatever it is that restrains you is what owns you. And the only way out is to recognize what that is: it's the old you, the one that got "drowned" in Baptism, but as a wise pastor once said, that old man learned how to swim and popped back up. That's why Luther said we have to die daily in our Baptism: that old self just keeps popping up.
So it doesn't matter if overeating is a disease or not, because that's not the real battle. The real battle is throwing off the yoke of bondage, the set of rules you have shackled yourself with that keep you from being free.
I hope you've talked with your pastor about this already. But since I don't know, in my brashness I'm going to charge ahead with some thoughts:
You give into food, and that makes it your enemy. Don't worry about why you give into it -- instead, attack. My thought here is to find a retreat you can go to where everyone will fast for one day. Whatver their reasons for fasting, yours will be to tell the food, and through the food all the rules that bind you, that they don't own you. They don't own you because you were bought with a price, not silver or gold, but with the precious Blood of the Lamb. HE is the one who owns you, and because He does, you are free to tell that food that it can just begone for a day while you and your Lord own you and you spend time with Him.
And when the Devil comes knocking with the whines about how you can't feel good about yourself -- because that's where it comes from, the Father of Lies -- then you just say, "I am covered in the waters of Baptism. They surround me, and if you, devil, want to bother me, you are going to have to swim them. That water has Jesus Name all through it!"
And when you remember your Baptism, remember why it is powerful: because in that Baptism is Jesus' death, and that death says that you are more valuable than a myriad of galaxies, more valuable than an undending banquet, because He made you as valuable as His Blood by shedding it for you.
And when your old self whines there's nothing about you to feel good about, don't argue -- say, "Self, you may be right. But Jesus died for me, and made me His own. He washed me, and took me home, and that's something more good than you can ever understand."
Maybe you can say it in your mind, but I find it helps to say it out loud, even if only quietly: Jesus died for me.
By the way, that's one reason Paul said, "We preach Christ Crucified". It isn't the miracles, it isn't the Resurrection even, that say how much we're worth, it's the Cross, and it says that we're worth the Blood of God.
And you are: you, Lisa, are worth the Blood of God. He said so.