Pick yourself up, thats the first step. Recent studies are pointing Binge Eating as more of a physiological (think hormones) imbalance than a mental once, so you can forgive yourself if you thought it was some character fault which caused it.
What happens in many cases is an imbalance and low level of serotonin, a hormone that increases a sense of well-being. Causes for low serotonin include low carb dieting since carbs are what allow the 5-HTP protein, which is the precursor to serotonin, to enter the blood-brain barrier. Another common cause for low serotonin could simply be genetic or physiological. There are a few ways to try and increase your natural serotonin levels such as taking 5-HTP supplements, which have been known to help since a higher concentration of 5-HTP means more will diffuse into the brain, or just increasing daily carb intake.
So how does psychology play into this? Well our minds are powerful controllers over our bodies. Many times, if we believe something or feel a certain way, it will manifest itself in our bodies. So for example, you have been binging and feeling shitty about yourself. As you continue to binge, you just keep telling yourself this will be the last time and you'll be good in the future (while of course stuffing more pizza and cakes into your face since you've just set an ultimatum for yourself so hey, its okay to stuff your facenow since you won't do it anymore, might as well get it all out of the way right?). But by doing this, by setting up this "last supper" scenario, your serotonin and endorphins remain low since you are putting so much mental stress and cognitive dissonance on yourself for bingeing. In effect, your eating all these unhealthy foods yet you're not getting the benefit you should of the skyrocketing serotonin, endorphins, and leptin since your mental stress is blocking their actions. You never feel the stop signal despite clear physical signs of satiety such as a hurting, bulging stomach. This just further bolsters the observation that binge eating is hormonal, since clearly it is not physical. We all know how powerful hormones can be, they ultimately have the last say. If they want you to be fat, you WILL get fat. If they want you to be thin, you will get thin. Just look in nature from hibernating animals to pregnant women etc. [By the way, when I posed that example of stuffing your face, I don't mean you personally, I have no idea how you behave, but this is merely a general observation.]
So what do you do?
1. Get some supplements into your diet. Essentials are omega-3 fatty acid supplements, but others are 5-HTP or tryptophan.
2. If you find yourself in a binge, DO NOT beat yourself down during it. You're just going to keep stimulating your desire to eat since your essentially telling your body you plan on restricting it in the future, which will only stimulate the urge to binge more and horde food while its available. I want to also note that any type of plan to restrict will have this same effect, not merely calorie restriction. So for example, the classic case of binge eaters is to promise themselves they will fast or purge themselves after a binge, this is one example of depravation. But another case, and this will probably occur more among primal followers, is not the plan to restrict calories, but perhaps restrict the type of food you eat, such as swearing off of pizza, grains, dairy, or carbs or whatever in the future. It doesn't matter what it is you want to restrict, your brain doesn't care, all it knows is that you plan on depriving it in the future and thats the message it will send your body. Again, the "last supper" scenario. But ask yourself this? How many times have you actually heeded to your own promises of no future binges? Hasn't really been working yet, right?
3. Instead, when you feel a binge coming on, ask yourself what you want to eat, I don't care if it's the most unprimal food. If you don't satisfy your craving, your just going to continue harboring feelings of depravation until you cave. Get whatever it is you want to eat, lay it all out on a table in front of you - I don't care if it's a huge grand-daddy stack of pancakes, a burger, and ice cream - if you're going to binge on it anyway, you better fucking enjoy it. Sit down, take out a fork and knife, take a slow, calm inhale of all the smells of the food in front of you. Enjoy the smell. Smile. And finally, slowly dig in, knowing its all there for you to eat. As you eat, continue repeating to yourself that all this food is for you and you plan on eating it all. Mentally repeat to yourself that you are in no way going to punish yourself for eating this. You will probably find the extremely frantic feeling characteristic of a binge will be completely removed.
But the catch is that you can't go in expecting this lowering desire to binge - almost a catch-22 since if you're expecting to eat less, then your just setting yourself up for disaster again since you're EXPECTING to not eat all of it. Just eat giving yourself full permission to eat it all.
Why do I know all this, where do I have the authority? Well I don't, I'm not a doctor, a pharmacist, or dietician. I'm only a premed student, but I have worked at a eating disorder clinic, and I've seen first hand how this set of advice has worked wonders on stopping binge eating in patients.
Side note, I don't doubt at all that I will get bashed by possibly many people on these boards for this seemingly harmful advice, especially the advice to eat nonprimal foods if so desired, but I believe eating disorders are MUCH BIGGER PROBLEMS than something like eating primal. Honestly, it's not even a comparison.An eating disorder can, and has, ruined people's lives, their relationships, their friendships and professional lives. FIX YOUR EATING DISORDER before worrying about eating primal.
A healthy-minded SAD eater is, imho, in a much higher state of well-being, than a primal binger. If that's the whole goal of primal anyway, to increase your well being, then how can you accomplish this if you continue to binging, right?