Items on your plate are smaller than they appear: Portion distortion in EDs

Search for the term “portion distortion” online, and you’ll find an array of evidence that portion sizes of food have increased dramatically in the past few decades. It’s not uncommon for me to see muffins the size of my head. While there is nothing wrong with large muffins per se, there is also little doubt that, especially in restaurants, we are usually served more than in the past.

For someone with an eating disorder, identifying the proper portion becomes even more difficult than your average John or Jane Doe. People with eating disorders generally have a variety of rules about what they can and can’t eat, and they not infrequently weigh and measure food, down to the last gram and grain of rice. Eyeballing proper portions can be even more difficult, due to the psychology particular to eating disorders. Several studies have shown that, when it comes to estimating proper portion sizes, people with eating disorders generally dramatically overestimate the amount of food they have on their plates.

Portion distortion in anorexia nervosa

This is perhaps the type of eating disorder that is most frequently associated with portion distortion. Some studies, like one published in the Journal of Marketing Research, have linked underestimating portion sizes with obesity (Chandon & Wansink, 2007), but obesity is not actually an eating disorder. Still, it’s not unreasonable to hypothesize from this data that maintaining an underweight status might be correlated with overestimating portion sizes.

Despite the relative importance of such studies to the treatment of anorexia nervosa–learning to properly estimate how much you should be eating is a pretty basic skill in normalizing weight and nutritional status–studies are very few. One 1988 study in the British Medical Journal found that patients with AN significantly exaggerated the size of food portions compared to healthy controls (Yellowlees et al., 1988). Another study found that both AN sufferers and healthy controls underestimated the amount of food in front of them. In this study, the participants had to guess how many objects (either candies or plastic LEGO toys) were in front of them, and both groups equally undercounted (Vinai et al., 2007). The most recent study was just published in January 2013 in the journal Appetite by a group of Swiss psychologists (Milos et al, 2013). The researchers compared a group of 27 healthy control women with a group of 24 women suffering from anorexia. The researchers didn’t measure how long the women had been suffering eating disorder symptoms. All study participants were instructed to eat a normal meal 2 hours before testing.

All of the women were instructed to look at computer images of three different meals: a breakfast (consisting of bread, butter, jam, yogurt or
muesli, orange juice), and two different dinners (Meal A: meat, risotto, broccoli, fruit salad, with or without ice cream; Meal B: lasagne, salad, applesauce with vanilla cream). The researchers showed pictures of different portions of these meals, from 1/8 portion to 1 3/4 portion, and the women were asked to rate the size of these meals on a scale of 0 (small) to 100 (large). For some of these ratings, the women were asked to rate the portion size as if they were going to eat them; the researchers called this the “intent to eat” condition.

Across all different portion sizes, the AN patients estimated the food in front of them 7.6 points higher than healthy controls. These results were more significant when they were estimating the size of small (1/8, 1/4, and 1/2) and medium (1) portions. For the larger portion sizes, both groups estimated sizes to be the same. The researchers also found that the women with AN estimated portion sizes to be even larger in the intent to eat condition than when they were just making guesses about the food without thinking about eating it. The healthy controls estimated portion sizes similarly regardless of whether they were thinking about eating them.

Conclude the authors:

The tendency for AN patients to overestimate small and very small meal portion sizes could explain why, when even well motived to gain weight, AN patients ingest insufficient quantities of food. AN patients may feel very uncertain regarding correct portion size and may weigh food to ensure that the serving is adequate. Thus, “How much should I eat?” is a frequent question of AN patients to their therapists.

The researchers linked this portion distortion in AN to anxiety, citing earlier studies that showed anxiety went up in AN sufferers when they were presented with food, which they hypothesized was linked to food avoidance and underestimation of portion sizes (Friederich et al., 2006; Ellison et al., 1998) {Today in painfully obvious research…} It is, perhaps, this research that helps explain what is going on. The fear of food that accompanies anorexia makes people unconsciously overestimate portion sizes. It would be interesting to see whether this normalizes with recovery, and if targeting this phenomenon helps patients achieve remission.

Portion distortion in bulimia nervosa

Anorexia sufferers aren’t the only ones who have food fears; they occur in BN as well. These food fears can, in some cases, be more grounded in reality and thus harder to counteract. Food fears aren’t as simple as “If I eat this, I will gain weight,” they can also be “If I eat this, I will…” lose control, lose my mind, keep eating, etc. Since people with BN do binge eat, their fears aren’t completely ungrounded. However, avoiding a feared food makes someone obsess about it and desire it even more, thus priming the person to binge eat. Figuring out how to eat feared foods in moderation is one of the primary goals of BN treatment.

The only research article on the subject that I could find was a poster presented at the 1995 conference of the American Dietetic Association (Stang, Story, & Zollman, 1995). The researchers surveyed 132 BN patients who were receiving treatment and assessed their accuracy at determining portion sizes of 25 commonly consumed foods. They also asked the patients how “safe” they perceived the foods. For 20 of the 25 foods, the patients estimated the size less than 50% greater than the actual size. For 5 of these foods, however (in the online information, the researchers did not specify what these foods are), the patients estimated the size to be more than twice as big as they actually were.

Breaking the data down by patient, the researchers found that 66 patients overestimated portion size of at least one food by 300%. Twenty subjects estimated portion sizes greater than 500%. The researchers found a trend that indicated the more “unsafe” the BN patients rated a food, the more they overestimated portion size. The researchers concluded:

Our results suggest that the ability of bulimic subjects to estimate portion sizes may be affected by the psychological safety factor associated with that food and, to a lesser extent, any previous experience in measuring foods. These factors should be considered when assessing the dietary intakes of bulimic subjects.

Putting it all together

So what causes this? What factors contribute? Interestingly, the best theoretical framework for figuring this out comes from research on spider phobias. A study published in the Journal of Anxiety Disorders found that people with spider phobias consistently overestimated the size of a spider compared to non-phobics (Vasey et al., 2012). They also did this even after treatment. What was interesting is that the more the spider phobia patients were afraid in the moment, the more they overestimated spider size. It wasn’t related to their general levels of spider phobia, just how afraid they were when the actually saw the spider.

In the Discussion section, the researchers developed a set of three different means through which this size overestimation might be happening.

  • Theory 1: People with a phobia towards what they are viewing may pay less attention towards the phobic object. This could decrease the amount of accurate information they collect about the object, leaving them to rely on their fearful, emotional responses. (e.g., “I don t remember its size very well, but I was terrified, so it must have been huge!”)
  • Theory 2: People with a phobia towards spiders pay less overall attention to the spider itself and instead focus on specific aspects of the spider, such as its ability to move or bite. In EDs, patients could focus more on the fat content or the food’s potential link to weight gain rather than the actual food itself.
  • Theory 3: People with phobias could be remembering the object as being larger than it actually was. Fear might have influenced memories of the feared object and perhaps amplified its size. Current anxiety only makes these memories more distorted (“If I feel this anxious, the spider must have been huge”)

A study in the International Journal of Eating Disorders found that ED patients actually paid more attention to food pictures, making the first theory less likely (Shafran et al., 2007). But it has yet to be formally assessed.

It strikes me as odd that this phenomena has yet to be more formally studied in the field of eating disorders. There has been much more research into body size overestimation, but virtually none in the arena of food portions. It’s something that can easily frustrate people, since patients can lose weight when they think they’re eating normally. Alternately, it makes patients freak out when being served normal portions and treatment providers get frustrated at such an exaggerated response to what looks like a normal meal. I think it would be interesting to see how and if this portion size overestimation changes over treatment and whether it can be specifically targeted in ED treatment.

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8 Responses to “Items on your plate are smaller than they appear: Portion distortion in EDs”

  1. Or… maybe genius treatment providers could come up with calorie packed teeny weeny sized portions, that wouldn’t scare the hell out of us, and would refeed us and help us gain weight and brain power anyway… with just a little less trauma. Wouldn’t that be nice???

    • That would be awesome! Or like special portion viewing glasses, to trick our brains into accurately seeing what’s there.

  2. I realize that HM’s comment was said in jest, but I also think that speaks to some of the issues associated with “treatment,” at least from my experience. When hospitalized, you are in such a sterile and secluded environment that in no way prepares you for “reality” once you leave. I understand this is completely necessary in most cases so that many patients can actually regain their health, weight and brain functioning, but once you leave that safety net, you’re on your own.

    Ensures, high-fat food in compact packages (nuts, avocados, etc.)and the like are the key to the “large portion” conundrum, but it’s hard when you’re released from such a supervised environment to keep up with the larger portions you were exposed to in treatment. You get used to “your normal” through isolation, and the exposure to what is actually “normal” and in most cases much more than the average person is required to eat is a shock. When discharged, it’s easy to slip back and justify the smaller portions as more average.

    All this rambling is to say that I love food and never feared it, but I have anxiety surrounding the increased amounts or change in routine associated with all the food. The only way to get through that is through repeated exposure and pushing myself past what I think is “normal” to what’s required for me. Easier said than done, and a teeny weeny sized portion that could deliver it wouldn’t eradicate the problem. It’s about building a new relationship, one that I’m still struggling with. Great post ;)

  3. As a child of the ’70s, I’m still waiting for food in the form of pills. We were promised it, along with jetpacks and other futuristic stuff. Pop a pill instead of eat?? I’m all for it :D

  4. Exactly how long did it acquire u to create “Items on your plate are
    smaller than they appear: Portion distortion in EDs | ED Bites”?
    It carries an awful lot of great knowledge. Appreciate it -Amee

  5. I found this article interesting.
    I have just come back from presenting a workshop at the scottish eating disorder conference last week. I was thinking about this concept of portion and distortion and exploring this area more. I work in an inpatient unit as a CBT therapist and am looking at ways to help staff and patients manage eating less distressed.

    I really think if people with eating disorders had evidence that this happens when they saw food. It could help them face food and maybe less anxious.

    But also train staff not to judge that patient are just wanting to eat less but struggle with portioning and their anxiety effects this.

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