What's The Point of Bingeing and Purging? And Why Can't You Just Stop?

I defended my MSc on Tuesday and I’m not going to lie: I was pretty symptomatic with bulimia in the days prior to my defence. As I explained to my boyfriend: the anxiety-reducing effects of purging are so powerful, and the compulsion to binge and purge (when I’m stressed/anxious/”not okay”) is so strong that it is much easier to do it, get it over with, and continue working (in a much calmer state).

I’ve mentioned before, for me, purging is very anxiety-reducing and in some ways, almost a positive experience. It is so tightly coupled with bingeing that it is hard to separate the two, but the anxiety-reducing effects are strongest when I binge and purge, non-existent when I binge, and weak when I purge a normal meal (which is exceptionally rare/almost never.)

It turns out, of course, that I’m not alone.

Negative emotional states and stressors have long been associated with bingeing and purging (b/ping). In particular, they were thought to precede (or occur before) b/ping events. But of course, anecdotal evidence from clinical practice, while important, is not scientific.

Several small studies have been done to examine the relationship between emotional states/events and b/ping behaviours. In 1982, Johnson and Larson had 15 BN women and 24 control women keep a daily diary for a week (with recordings 7 times a day). They found that negative moods preceded b/ping events and that women with BN had more variable mood states and were generally less happy (more dysphoric).

Since then, several other studies have attempted to answer this question. In general, they found that bingeing/purging is preceded by low mood and/or high stress levels. But the studies are not without problems. For most, the sample sizes are quite small and many relied on retrospective reports (subject to memory biases).

A few years ago, Joshua Smyth and colleagues published a study that tracked mood, stress, and bulimia nervosa symptoms in 131 women with BN over a 2 week period. In order to avoid retrospective reports, they used something called the ecological momentary assessment or EMA. Essentially, it allows researchers to collect data in “real-time.” The participants had to report on mood, stress, and BN behaviours at six semi-random time points during the day in response to a signal.

Smyth wanted to compare (1) the mood and stress reports on days with bingeing/purging events and days without b/ping events and (2) the mood and stress trajectories prior to and following the first b/ping event of the day.

Over the two weeks, the women reported an average of 8.5 binge eating episodes and 11.5 purging episodes. Compliance with the EMA was also quite good (86%).


Non-B/P days vs. B/P days
Unsurprisingly, Smyth et al. found that the women experienced significantly higher levels of negative/unpleasurable mood states, anger, hostility, and stress and less positive moods on days when they engaged in bingeing and purging. This is not surprising as it supports previous research findings dating back to 1982.

Before B/P vs. After B/P
What’s more interesting is to see how mood states and stress levels changed before and after bingeing/purging. Smyth et al. were interested in the changed before and after the first bingeing/purging event.

Here’s a summary figure of what they found:

Smyth - 2007 - Figure 1 Adapted

As you can see, there was a rapid drop in negative affect (aversive mood states), anger/hostility, and stress levels following bingeing and/or purging and an increase in positive affect (positive mood states).

What’s more, the rate of “recovery” of these mood states was significantly more rapid following the bingeing/purging event than their “decay” prior to the event. This is interesting and I must admit, kind of cool to see in print, because it wholeheartedly supports my personal experiences.

Smyth et al.’s use of the EMA and the large sample size add stronger support to previous, small and often retrospective, studies.

The EMA provides a unique opportunity to examine the potentially (affectively) reinforcing nature of engaging in bingeing or vomiting behaviors for women with BN.

On a more global level, BN-events are quite negative. That is, BN-events commonly occur on days with significantly “worse” moods and, even at the moment when mood is best on BN-event days, moods are more negative than on days when no BN-events occur.

In sharp contrast, however, the proximal (or local) mood trajectories around a BN-event appear to hold markedly different reinforcing properties (at least for women with BN; cf. Wegner et al., 2002). Mood significantly worsened (less PA, more NA and AH) leading up to BN-events but improved (significantly more rapidly) following the event.

This suggests that, local to the event (i.e., within a few hours), bingeing or purging behaviors are strongly negatively reinforcing as they allow escape/ avoidance of a strongly negative affective state. This (local) reinforcing pattern provides support for the persistence (and resistance to change) of binge and purge behaviors, yet is also consistent with the view that such behaviors are not effective overall (global) coping efforts.

YES! THIS! I couldn’t have said it better myself.

Negative reinforcement sounds like a contradictory thing, doesn’t it? But what it means is that something is reinforcing because it removes a negative condition. In this case, bingeing and purging is reinforcing because it removes the negative mood/state.

Generally, my mood is much lower on days I binge and purge, particularly if I do it more than once. But, my anxiety/stress levels drop sharply following the first binge/purge episode. The drop in negative mood states decreases with each successive b/p (for me) and I think that’s for a few reasons. One, as I’ve blogged about before, there are powerful physiological processes that predispose one to “marathon/chain b/ping” (namely, a drop in blood sugars to fasting levels following purging), and two, I get progressively more annoyed with myself and physically tired.

In any case, I’m interested to hear what you think about these data and whether they reflect your personal experiences or not! Let me know in the comments.


Smyth, J., Wonderlich, S., Heron, K., Sliwinski, M., Crosby, R., Mitchell, J., & Engel, S. (2007). Daily and momentary mood and stress are associated with binge eating and vomiting in bulimia nervosa patients in the natural environment. Journal of Consulting and Clinical Psychology, 75 (4), 629-638 DOI: 10.1037/0022-006X.75.4.629

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Tetyana is the creator and manager of the blog. She has an Honours BSc in Neuroscience and an MSc in Medical Science. She can be reached at tetyana[at]scienceofeds[dot]org.


  1. I definitely relate to the soothing effect of bingeing and purging. For me, I don’t think there is a way I could get through the day sometimes without knowing that I have it to look forward to, even though I find the actual practice of purging very unpleasant.

    I find it gets perpetuated from the ‘high’ of looking forward to and then eating FOOD, by the starvation, and the high I get when I’ve gotten everything out of my body. Or ‘high’ isn’t really the right word… I feel relief. I am soothed, but at the same time I perk up. When I’ve purged, if you know me really well you can tell, because all of a sudden I’ve gone from anxious or upset or just my usual preoccupied self to ‘happy happy’ almost giddy. It’s a lightheaded, speedy feeling sometimes, almost like it’s given me bipolar moods and I go spinning upwards after purging until I come down with a crash again even lower.

    I definitely also get the chemical problem where purging has given me a chemical crash – I always thought very low blood sugar because I would start shaking uncontrollably and be close to passing out, and know that I had to get something into me desperately, which would be too much for me to cope with and end up being a binge again, continuing the cycle.

    It’s not just purging after a binge, I can’t seem to cope emotionally or physically any more with ANY food in my stomach most of the time. It’s not just about it being uncomfortable or painful physically – emotionally, I can’t cope. I want to die, my mood just bottoms out.

    Definitely on a global level the bingeing and purging makes things worse overall.

    My biggest problem is how to stop purging forever. I don’t think I could ever do that – it’s too ‘normal’ to me now. It feels as essential as breathing to purge.

    I’m glad you have your MSc over now – congratulations!! that’s awesome! What next for you?

    • I totally relate to this, in the restrict/binge sense. Anytime I feel uncontrolled stress, the first thing I want to do is restrict as much as possible (until I get very weak and light-headed) and then binge for relief. The foods taste so much better (because I’m starving and need that nutrient intake) and I feel so relieved in the moment. Unfortunately, I usually just end up depressed for the next few days with major indigestion…but yeah, it definitely gives me something else to focus on when I have serious doubts about the rest of the world.

      Good find!

      • Do you have major indigestion following just one b/p? I have issues if I do marathon/chain b/ping, but usually one b/p doesn’t do anything for digestion issues. I do have to stay away from hard-to-digest but unfortunately safe foods. It is interesting, too, because b/ping doesn’t really have long-term negative consequences for me like that. I sometimes have forgotten that I’ve done it earlier in the day; I’m really good with just moving on. It sort of depends on a lot on why I did it: if it was more because I was restricting (so physiologically needed the calories), I feel okay, but if my mood was low, then I tend to come back down and feel like crap after.

        It is weird talking so publicly about this. I forget my sister and my dad know about this blog. Ha.


        • Haha…yes, let’s talk about our bowels like old people!

          I think my issue was that I wrecked my digestive system from years of malnutrition, so I basically lack the ability to process foods when I binge, making the issue worse. Probiotics have definitely helped (and eating more regularly).

    • “I find it gets perpetuated from the ‘high’ of looking forward to and then eating FOOD, by the starvation, and the high I get when I’ve gotten everything out of my body. Or ‘high’ isn’t really the right word… I feel relief. I am soothed, but at the same time I perk up. When I’ve purged, if you know me really well you can tell, because all of a sudden I’ve gone from anxious or upset or just my usual preoccupied self to ‘happy happy’ almost giddy. It’s a lightheaded, speedy feeling sometimes.”

      Yes, this. Though again, it kind of depends. I try not to purge too much to get to the point of being lightheaded anymore. And also, if I’m marathon b/ping, that feeling QUICKLY fades and everything becomes crap. Food tastes like cardboard and purging sucks, I almost can’t stop. I also find that thrill and “high” after following b/p’s that I plan/allow myself, and not so much ones that happen absolutely by accident.

  2. I went about my bingeing and purging in a different way. I would set myself weight goals before I was allowed to binge, or tie bingeing in with events that I couldn’t avoid, where I would have to eat. I didn’t allow myself to be free enough to binge according to my moods.

    • That’s interesting–do you mind expanding a bit? What do you mean “tie bingeing in with events that I couldn’t avoid”?

      For me, I often get so agitated and jittery that I pretty much *have* to do it to get rid of that feeling and be productive/work. The key for me is not to get to that state or abate the mood REALLY early on, because once it progresses, I can procrastinate a b/p for a few days, even, but the urge will still be there.

      • Yes. If say my mother was due to visit me for a few days in three weeks’ time, I would designate her visit as a binge period. In the run-up I would restrict by maybe xxx calories per day. And I would buy in all the food I was craving during the restriction to eat during her visit.

        Otherwise, I would do it by weight goals. So I might decide that I was allowed to binge after every x stone (that’s British for seven pounds) that I succeeded in losing.

        So, my binges were premeditated. I also used charts to control myself, like the ones I have on my website here: http://www.lesbian-crushes-and-bulimia.com/bulimia-charts/

        (I edited out the numbers because I don’t think they are necessary to illustrate the main point and might be triggering for some. – Tetyana).

  3. I am so proud of you. Thank you for sharing your tremendous accomplishment of defending a MSc. WOW! thank you also for being so honest with your personal expierience. I am beyond excited by the data that you presented and I am grateful for your work. Your words I can relate to with accurate precision. You are amazing.

  4. Great post Tetyana! And congratulations on defending your thesis!

    Even though I don’t have BM – I literally can’t make myself purge – I can relate to your post in terms of chew/spit. The urge to engage is noticably stronger on days I’m stressed, and giving in helps relieve the pressure. Although there aren’t any studies on this, I wouldn’t be surprised if the same mechanism – that is, negative reinforcement – is a driving force for c/s.

    • I wonder what may underlie this “negative reinforcement” as well. Do you guys think there is something to the “ritual” of ED behaviors? Might all these ostensibly diverse behaviors (bingeing/restricting, bingeing/purging, chewing/spitting) all activate similar corticothalamic pathways in reward circuits? I’m wondering where all these behaviors converge, and also diverge?

  5. The changes to positive and negative affect following b/ping are not surprising at all. This pretty much illustrates my experience as well. I happened upon a study in Comprehensive Psychiatry about Post Traumatic Stress Disorder changing the negative affect of BN sufferers. Karr et al. found that sufferers with PTSD and BN experienced more negative affect more quickly and they b/ped more often than the BN group (control).

    It was only a small study, but these are the details if you’d like to read it: Karr, Trisha M., et al. (2013). Posttraumatic stress disorder as a moderator of the association between negative affect and bulimic symptoms: An ecological momentary assessment study. Comprehensive Psychiatry 54.1 (2013): 61-9. http://dx.doi.org/10.1016/j.comppsych.2012.05.011

    I found it applicable to me because I have both PTSD and BN, so the link is worth investigating I think.

    • Thank you! I will read the study. I appreciate the link.
      I quite like the work that Stephen Wonderlich is involved with. Seems like a lot of EMA studies lately, too.


  6. Although I have BN, my sister has and I have seen first hand that your finding are correct. She would always seem to be in a better mood after she had b/p. It was scary for me to see just because I did not know anything about it. It is always interesting for me to look into these subjects and uncover all the ins and outs that BN connects too. For the average person who does not b/p, they may think it is because of a weight problem, which I think is a safe assumption most people make. At least it was always what I thought. The interesting part is that no one looks at it as a stress re-leaver. Much like smokers, who are having a bad day or are in a bad mood who just want to release some stress, b/p can be the same for different people. They both can be harmful for your body, but can help with a bad day. Using b/p as a negative reinforcement is what is most interesting to me because it is hard for me to think of it as reinforcing in order to be in a better mood, not saying it is wrong, but just different for someone to think about who has never experienced before. As far as these findings go I am interested to hear more and learn more about the details the negative reinforcement brings about.

  7. This article really resonates with me because I have discovered that the purge aspect of my BN, is just as “rewarding” to me as the Binge aspect. Whenever I am stressed or anxious or frustrated, the binge is what I think of as being my escape but the purge is the physical expression of relieving myself of all my stress, anxiety and trouble. I find the feeling of purging extremely cathartic and a calmness washes over me after it is done. Currently in my recovery, I find it interesting that the urge to binge has lessened tenfold (now that I am no longer starving myself), however, I psychologically miss the purge aspect and how it made me feel… something I never would have expected.

  8. Even though I have weeks during which I engage in purging, it’s difficult for me to understand the elation that many seem to feel after vomiting. I find it quite traumatic (it is also rather difficult physically to bring the food back up, so there is always the uncertainty whether I’ll get fat from what stays inside) and unpleasant, my heart races afterwards (the opposite of calmness) and I feel weak and depressed, just want to lie down and sleep for the rest of the day (which also means I can’t do the workouts I’d scheduled for later in the day, which distresses me even further). It also lowers my defences and primes me for another binge (which, in my case, is either a healthy small meal, a bowl of cereal or a handfull of cookies, not huge amounts of food).
    I really can’t relate to any positive feelings about this…

    • Hi Zayna,

      You alluded in your earlier comments that non-purging bulimia nervosa is more closely aligned with your diagnosis? (Sorry if I misread/misunderstood). If that’s the case, it makes sense why you wouldn’t experience a decrease in negative feelings (different from an increase in positive feelings). I certainly only began to feel the strong negative reinforcement of purging after a few months of purging on a semi-regular/regular basis. It is also more negatively reinforcing for me with a “good” purge (where I am not anxious about the food I didn’t bring back up).

      I do think it is important to remember that it is not necessarily positive feelings as much as a removal of negative ones. Obviously, that removal will be minimized if purging itself is difficult and you experience anxiety over food left unpurged.

      Moreover, the timescales we are looking at is also important. I feel purging is strongly negatively reinforcing for me, but that doesn’t mean it is all or even MOSTLY positive. I also tend to feel weak, and soon after purging, my mood drops because I’m annoyed at myself for bingeing/purging, for example, and then there are all the physical symptoms (like inability to digest food after, especially if I go on a string of binges/purges).

      And yes, it does prime you for another binge, I discussed some possible reasons for that in another post (basically, a huge drop in blood sugars).

    • Just to add, I think it is a great thing you DON’T feel the elation because experiencing that feeling really makes it so much more reinforcing.

  9. I have also never found purging to be reinforcing–it’s all about the binge. Tension and pressure build and build until it’s unbearable and the binge releases that, so it is negatively reinforced. After binging I drop quickly into depression (not the same unbearable tension as pre-binge) and dread purging. I have been b/p for a long time now but I’ve never felt anything positive from purging, it’s simply a response for the self-hate from overeating. I would almost say it is a punishment…it’s an oft-used thought pattern in which I try to convince myself out of a binge, because I know I’ll have to purge afterwards.

  10. For me, b/purging is a very effective/semi-safe coping mechanism. Whenever my anxiety/stress/anger level shoots over the roof, I plan a mini b/purging session to relieve the tension. With that being said, my binge is never big [content cut by Tetyana], and is very carefully timed and executed, so it doesn't cause too much guilt or make a big mess afterwards. The binging part is very boring and tedious, while the purging is extremely cathartic. Every bit of food I throw up represents my stress, my frustration, my anger or even the people who I hate so much yet have to pretend to like. Purging takes away the weight/burden of life on so many levels. I feel vindicated when I abuse my own body, yet knowing that it's safer than what my peers are doing to relieve stress (don't have to worry about cirrhosis from inebriation, STDs from sleeping around, or blacking out/injury from intense workout). On the physical side, I feel calmer after a good b/p session so I can return to my study, or extremely tired so I can slumber off rather easily. So yeah, I absolutely agree that B/P can improve one's mood. However, sometimes I do feel like I am trading a very dangerous line…but hey come on, half of the people in my class are alcoholic who reside in a manically happy bubble and the other half are clinically depressed who will at one point become alcoholic/suicidal, as long as my b/p doesn't leave me with a perforated abdomen or aspirated pneumonia…it's all good.

    • This is truly scary for me to read… and so much denial. Yes I think you ARE treading a very dangerous line and you don’t fully realise how dangerous what you are doing IS. It is FAR more dangerous than what your peers are doing – more deadly than alcoholism, more deadly than depression, and you risk dying of more than aspiration or perforating your abdomen, you are more likely to drop dead of a heart attack from electrolyte imbalance. If you make it, you are likely to suffer terrible medical consequences that haunt you for the rest of your life. It’s not a safe way of coping at all. Please, please reach out for help. Your state’s eating disorders service is a good place to start.

  11. FM are you a GP by any chance? There is NO denial in all these comments. I have been in counselling for 15 years and on medication in an attempt to conquer my b/p. It is a terrifying fairly horrific thing to deal with daily. Reading these heartfelt comments makes me feel less alone/mad/terrified. I have found some health professionals the least understanding and quite lecturing. Pluck up huge courage to go and see your doctor and to be told what you are doing is hurting yourself is unhelpful and ridiculous. WE KNOW THAT. This type of forum makes me feel supported and gives me hope. Thank you.

  12. I used to feel mentality awful when I purged as I was judging myself on so many levels. But now I have stopped judging it. It happens and I do feel a huge tension relief in terms of mental state afterwards compared to before. I would prefer not to do this behavior but it does happen now and again. The message to myself that there is something wrong with me, I must stop this, I must fix myself. …does not help. There will always be things to improve about ourselves. It’s a occasional coping mechanism and it works.

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