If a person severely restricts his diet and exercises for hours each day, he has an eating disorder. If another does exactly the same but it is because she wants to make the lightweight rowing team (which has an upper weight limit), she’s a committed athlete. When the two overlap, and an athlete presents with eating disorder symptoms, how do we distinguish between the demands of the sport and the illness?
I’ve been interested in the distinctions we make between disordered and non-disordered eating and exercise behaviours for a while now. Recently, when I was browsing through articles, I came across a literature review by Werner et al. (2013) (open access) of studies examining weight-control and disordered eating behaviours in young athletes.
The authors start by noting the sheer lack of research that has actually been done in this area. This is worrying: typical onset of eating disorders is during adolescence, and research indicates that athletes are more likely to develop these disorders, leaving young athletes in what appears to be a high-risk position.
Werner et al. searched …
Recently, I was browsing the Twittersphere and came across (yet another) tweet about so-called “drunkorexia,” or the phenomenon of drinking to excess coupled with restrictive behaviours around food. After firing off a mildly miffed tweet bemoaning our societal tendency to add the suffix “orexia” to all “new” potentially problematic behaviours around food, I took to Scholar’s Portal to see if academics, too, were using this term. I wondered if “drunkorexia” was piquing scholarly interest, or just circulating in media headlines.
Beyond its problematic moniker, coupling problem drinking and restrictive eating is a phenomenon that might be worth delving into in greater detail, particularly if, as the reports claim, its incidence is rising. Barry & Piazza-Gardner (2012) explored the co-occurrence of weight maintenance behaviours and alcohol consumption, and their article clarifies what people mean when they say “drunkorexia.” I’ll get more into my issues with this terminology following a brief overview of the authors’ study.
Alcohol and “Weight Management” Behaviours
Barry & Piazza-Gardner begin their article with reference to an interesting trend observed by those studying problem drinking in …
Genetics play an important role in the development of eating disorders and disordered eating behaviours. To date, many (over 30!) twin studies have been done and all but two found significant genetic effects on the development of eating disorders and disordered eating. However, no methodology is without limitations and tentative conclusions become more convincing when the findings are confirmed using different experimental approaches.
Twin studies, while they offer many advantages, are not that good when it comes to detecting shared environmental effects on a particular trait (literally, evens that happen to both twins and affect them in the same way). Fortunately, twin studies are just one of several different ways that researchers can use to study heritability. (A quick reminder: Heritability measures the amount of the variability in an observable trait/behaviour that can be attributed to genetic variation. This is NOT the same as stating that a particular fraction of an individual’s trait is caused by genetics.)
Adoption studies (scroll to bottom of link) provide a powerful alternative method to assess heritability and they …
The Tripartite Model of body image dissatisfaction postulates that three factors (peers, parents, and media) affect body image dissatisfaction and disordered eating through thin-ideal internalization and appearance comparison.
Thin-ideal internalization is the extent to which one accepts or “buys into” socioculturally defined beauty standards of thinness. The idea is that the more someone internalizes these standards, the more likely they are to engage in behaviours to achieve their “ideal”, and the more likely they are to develop an eating disorder.
A growing number of of studies have been done evaluating the validity of this model. Although I’m not well-read on the subject, it does seem like there is a growing number of studies showing an association between thin-ideal internalization and disordered eating practices.
But is the picture complete? Are peers, parents, and media the only or even the main factors that influence the extent of thin-ideal internalization?
One factor that’s curiously missing from the research is genetics. Can genetics play a role in explaining why some individuals are more prone to internalizing the thin-ideal …
I remember cutting baby carrots into 6 pieces. Rushing home to eat because I wasn’t “allowed” to eat after 7 pm. Eating the exact portion size–no more, no less. (Oh the rules. I don’t miss them.) Rigid food rules are very common among eating disorder sufferers. These rules can be about anything: the foods you are allowed to eat, how you are allowed to eat them, the time you are allowed to eat them, and so on.
But where do they come from? Why do some individuals have more rules and more ritualistic behaviours than others?
It is a complex question, but a recent study suggests that perfectionism might play a role. Specifically, the authors explored the idea that perfectionism mediates adherence to food rules in disordered eating behaviours. In order words, food rules might be a way in which perfectionism “expresses itself” in eating disorders.
Perfectionism has been identified as both a risk factor and a maintaining variable for disordered eating symptoms. In a prospective study, individuals with severe anorexia nervosa who scored highly
Puberty at an early age increases the risk for disordered eating behaviours such as bingeing and purging (Jacobi et al., 2004; Kaltiala-Heino et al., 2001). What’s more, the hormone estradiol moderates the risk of disordered eating behaviours. More precisely, in a group of twins with low estradiol levels, differences in disordered eating are likely due to environmental factors (such as family, school, friends), but in a group of twins with high estradiol levels, the differences in disordered eating are more likely due to genetic factors. (I blogged about it here.)
Essentially, estradiol partially moderates the extent to which genes affect disordered eating.
This is interesting because the estrogen system has a role in regulating body weight and food intake, influences eating behaviours during the menstrual cycle, and obviously plays an important role during puberty. Moreover, one study showed that estrogen receptor genes (proteins that bind estrogen) are associated with eating disorder symptomatology (Eastwood et al., 2002), though I don’t know if that finding has been replicated.
All of this is even more interesting because genetic effects on …
Last week, I blogged about a study that examined personality traits and clinical variables associated with excessive exercise in eating disorder patients. In that study, 2 out of 5 participants engaged in excessive exercise. Today, I’m going to discuss a study that suggests over-exercise in disordered eating patients is associated with suicide behaviour.
Suicide rates in eating disorder patients are high. One meta-analysis suggested that out of all eating disorder related deaths, 1 in 5 are suicides. (Keep in mind, these numbers are really hard to pin down as they depend a lot on the sample population, sample size, and how the authors did their statistics, among other things.)
Another analysis found that the standardized mortality ratio (ratio of observed deaths in the study sample/expected deaths in the population of the same age but without the disease/disorder you are studying) for suicide in eating disorders was 31 for patients with anorexia nervosa and 7.5 for patients with bulimia nervosa. Moreover, around 25-35% of bulimia nervosa and 3-20% of anorexia nervosa patients attempt suicide at least once in their lifetime …
Eating disorders typically begin in adolescence. One common explanation for this is that during adolescence females are increasingly exposed to the media, thin models, and dieting. While this is probably true to some extent, it doesn’t explain why the rates of eating disorders are quite low despite the high levels of exposure to thin models in the media. Out of 100 girls, only a handful develop eating disorders, yet all of them are exposed to the same magazines and TV shows.
This means there must be some other factors that differ between this group of girls. One hypothesis is that hormonal changes during puberty may modulate the genetic risk factors for eating disorders. These changes may “turn on” genes that predispose individuals to eating disorders. Previous research has shown that genetic factors modulate disordered eating (eating disorders have a high heritability), but how? What are the mechanisms of this modulation?
Exploring this idea, Dr. Kelly Klump and colleagues sought to focus on the role of estradiol–the predominant estrogen during reproductive years in females. Estradiol (and other hormones, …
When my younger sister first told me she wanted to become a vegetarian, I was worried. My biggest fear was that she would, like I did, develop an eating disorder. In high-school, I didn’t eat meat for roughly 14 months, and though I can’t be sure now of what my reasons were at the time, in retrospect, I do think in large part it was just a convenient way to avoid yet another food group. It was a legitimate reason to restrict my intake.
But is there any evidence that this behaviour (becoming vegetarian as a convenient way to restrict intake) is common among individuals with eating disorders? What is the relationship between dietary restraint, eating disorder symptoms, and vegetarianism? Is vegetarianism a risk factor for developing an eating disorder or do eating disorders lead many to adopt a vegetarian diet as a socially acceptable excuse to avoid eating specific foods? And, is there a difference between vegetarians that do not engage in dietary restraint and do not display eating disorder symptomatology, and those that do?
Thus far it appears …
Gender nonconformity is the second most popular search term that leads people to Science of Eating Disorders. (After “science of eds” and beating “science of eating disorders”.) Not far behind are variants of “FtM/MtF/transsexual/transgender” combined with “eating disorder/anorexia/bulimia”. That’s telling. It means there is little information on this topic. And it is not just that there’s too little information available to the public – there are only a handful of published studies in the peer-reviewed literature.
One study (which I discussed in my previous post: Gender Nonconformity, Transsexuality and Eating Disorders) published by Vocks et al (2009), compared disordered eating patterns, body image disturbances and self-image scores among trans women and men (131 participants in both groups) and cis female and male controls as well as to females with eating disorders.
Overall, they found disordered eating patterns reported by trans women and trans men were in the middle of those diagnosed with eating disorders and non-ED, cis controls. More specifically, trans women individuals had more severe disordered eating pathology than both female and male control groups, …