Rational Emotive Therapy

To me, this is the most useful type of therapy out there, at least for eating disorders. The point of the therapy is to have insights, and to dispute irrational thoughts and beliefs. In other words, you have arguments where you support and argue against your irrational belief, and then at the end you come to a conclusion. 
To do this type of thing with yourself you need to be open-minded and honest. The point of the therapy is to change your belief, so you can't give up halfway through when it seems like evidence for the belief outweighs evidence against it. You have to push yourself until you know you've explored ever nook and crevice of that thought, and presented yourself with all the evidence. 
The way I do it is I sit down at my computer and have a typed conversation with myself. I start out by pointing out my thought or belief (whether or not I believe it's rational or not) and then ask myself: why do you think that? From there, a conversation flows, where Therapist Emily questions Bulimic Emily's motives, desires, and evidence. This type of therapy is also really helpful in getting all your thoughts down, because it has to be so detailed. In that sense, it can be very therapeutic. 
The following is a very long example of this, but I will post the whole thing, so anyone who wants to can see how it can help break down destructive thoughts. 

Restricting makes me feel powerful and gives me a sense of motivation.

Why does it make you feel powerful?

Because I am in control of my urges. And my weight. Also, it means I won’t be sluggish from food or feel fat or anything. I feel thin and like I can handle things.

Why do you want to be in control of your urges?

Because losing control of them does not feel good. Also, my urges cause me to eat (at least the ones I’m trying to regulate) and gain weight. Also, focusing on controlling my urges distracts me from other things that I don’t like or can’t handle.

Such as?

Aspects of my personality that I don’t like, such as my apparent inability to make friends, and my social awkwardness, and my stupidity and stuff. Or things that I can’t handle like when it was Thanksgiving and everyone was starting to get anxious.

But you didn’t use restriction to feel in control then.

I did use restriction to be in control then. It was still less about handling things than it was about reducing my weight, which I focused on all the time. But consciously it wasn’t about trying not to deal with things.

No, you used food and throwing up to deal with that.

After that Thanksgiving, yes.

So your main reason for restricting was to lose weight?

Yes. The ultimate goal was to control my weight. It’s not about losing necessarily, I just wanted to exercise control to lose. But it was the control over it that I wanted.

Why did you want control it then?

So I could be in control of it. I like being in control of things, especially when I know I can control them well.

How do you know you can control your weight well?

Well, I have been able to go from 130 pounds to 115 pounds pretty well. I knew I could do it if I really tried. So then there was no excuse to fail.

So you wanted to lose weight to avoid failure?

Yes.

Why would failing to lose weight be failure?

Because I know that I CAN lose weight. So I should be able to.

But why even focus on that as a goal? If it’s not a goal, you can’t fail at it.

I thought that by losing weight I would become more attractive. Also, it gave me motivation to do things. It was my driving force. If I wasn’t restricting, I had no desire to do anything, and I gave up all endeavors pretty quickly.

So it looks like restricting makes you feel powerful because it motivates you to do things. You feel like you have control over your life, which makes you invest more in it.

Yes. It motivates me to care about myself. To exist.

Do other things motivate you to care about yourself?

Well, if I’m trying to impress someone. Like before I started dating my boyfriend, I wanted to impress every single boy I met because I wanted his attention. That motivated me to care. But in particular that motivated me to care about my WEIGHT. Mostly my weight, anyway. Nothing else really makes me care about myself. Sure, I do fun activities, but I don’t really care about myself. I just sort of enjoy life.

What happened to your motivation last time you stopped restricting?

When I was in Costa Rica and I was binging and purging every day, I had low motivation to do things. I made myself do them because it was part of the trip and I knew I would want to have the memories later, but I can recall being a little less motivated to care about myself during that period.

When you were in Costa Rica, you still wanted to do fun things.

Yes, I did. I did also want to rest more than I usually did. And I had no desire to shower, or try to contain my food intake, or brush my teeth, or write in my journal, or call my parents…

If you had done those things, how would you have felt?

Then I would have felt it was a waste of effort because I was getting fatter. I wasn’t taking care of myself in one way, so I couldn’t take care of myself in other ways.

What about when you started eating normally?

You mean on the meal plan? I still have motivation to do stuff. Not on the days I’m binging.

What you seem to be saying is that loss of motivation actually occurs when binging, not because of stopping restricting.

I guess. I mean, I’ve never really not-restricted without binging.

But if you did that, your motivation levels would be normal.

Yes.

And you would feel in control?

Only if I were losing weight.

What about maintaining?

If I was at a weight I liked then I would feel fine about maintaining. I did feel ok about maintaining towards the end of school when I was at 117. That was because I wasn’t binging, so I didn’t feel fat.

So you feel fine maintaining as long as you don’t feel fat or get too full.

Yes!

So you don’t care about losing weight, you just care about how full you feel.

Yes.

And feeling full makes you powerless.

Yes.

What will happen if you get too full?

I will gain weight.

Evidence?

I have gained 2 pounds in one sitting.

What about other times when you feel full? Do you always gain weight?

Immediately afterwards, yes.

Long term?

Not sure.

Why is gaining 2 pounds a bad thing?

Because if I can gain 2 pounds in one day, I don’t know how long that will go on for. I know I have a predisposition to be fat. And I refuse to let myself get that way. I know I can eat more than enough to become overweight.

And yet becoming overweight is not on that cons-of-recovery list.

Because I know it’s really unlikely for me to become overweight quickly. And because I know that I have the capacity to follow a healthy diet. One that isn’t restricting. And I think that by following the meal plan, and eating to when I’m full and not much after, I will not gain much weight. Five pounds at the most.

Will five pounds really hurt?

Not if they’re healthy five pounds that come on slowly.

Then you have nothing to gain by restricting! You can still exercise control over yourself by following the healthy meal plan, which will decrease the number of binges. And You said you still have motivation when you’re following the meal plan. You know that what you’re most afraid of: becoming fat, is not going to happen if you follow that healthy meal plan. So this con can be eliminated by following the healthy meal plan.

I’m still afraid of gaining weight. Any weight. But that’s a different con.