a source of thinspiration? - aric sigman

A source of thinspiration?

The Biologist Vol 57 No 3 October 2010

Over the past four decades women inindustrialised countries have becomewider, yet the ideal female physique,as depicted by the media, has

become thinner. Twenty-five years ago, theaverage fashion model was only 8% thinnerthan the average woman. Today that figurehas risen to 23% (Derenne & Beresin, 2006).During this time dissatisfaction with body sizeand shape has become so prevalent amonggirls and women that it is being described as‘a normative discontent’ (Grogan, 2007).

More worryingly, body dissatisfaction is nowappearing at increasingly younger ages. In astudy by University of Central Florida, nearlyhalf of the 3 to 6 year-old girls said theyworried about being fat. Around one in threewould change a physical attribute, such astheir weight (Hayes & Tantleff-Dunn, 2010).The use of diet pills among 15-17 year oldshas doubled in a five-year period (Neumark-Sztainer et al, 2006). Female preoccupationwith physique and body dissatisfaction doesnot appear to diminish across the age spansand is now even exhibited by pensioners(Tiggeman et al, 2001; Ferraro et al, 2008).

Yet body dissatisfaction is more than apsychological and cultural issue. The methodsused by an increasing proportion of girls and

Aric Sigman

A source of thinspiration?The biological landscape of media, body image and dieting

women to alter body shape are more thanmere stylistic exercises in aesthetics. Bodydissatisfaction has serious implications forfemale health and is a major risk factor for lowself-esteem, clinical depression, self-harm,substance abuse, obesity, excessive dieting,and mood and eating disorders. As bodydissatisfaction rises in increasingly youngerchildren, so too has the prevalence of eatingdisorders and dieting. In the past decade, therehas been an 80% rise in the number of younggirls admitted to hospital with anorexia inEngland (DOH, 2009). With a mortality rate ofbetween 10 – 20 per cent, the Royal College ofPsychiatrists states: ‘Anorexia Nervosa has thehighest death rate of any psychologicaldisorder.’ (RCP, 2008).

Neurological correlatesA meta-analytic review of 25 studies entitled‘The effect of experimental presentation of thinmedia images on body satisfaction’ concluded– as have others – that ‘body image wassignificantly more negative after viewing thinmedia images… mass media promulgate aslender ideal that elicits body dissatisfaction’(Groesz et al, 2002). This negative effect isfrequently reported to be both strong andimmediate (Tucci & Peters, 2008). Analyzing

Body image, dietingand eating disorders

are not a healthissue in Stone Age

societies (Irian Jaya,West Papua).

Photo by A. Sigman.

the brain activation patterns of females beingexposed to media images is now illuminatingthe biological landscape of body dissatisfaction.

Neuroscientists at Brigham Young Universityin Utah examined subconscious feelings aboutbody image through fMRI analysis of thebrains of healthy men and women who wereassessed psychometrically as being confidentabout their bodies.

It is known that when humans engage inserious self-reflection, activity increases in themedial prefrontal cortex (mPFC). It issuspected that this increased activation canbetray subconscious thoughts. When anorexicand bulimic women view an overweightstranger, the medial prefrontal cortex isactivated in ways that suggest extremeunhappiness and, in some cases, self-loathing.

In this study the healthy women looked atimages of avatar-like models in skimpy bikinis.Some images were overweight, some verythin. On viewing each image the women weretold to imagine that someone else was sayingthe model looked like her. When presentedwith overweight images, the mPFC showedincreased activation in all of the women. Merelyimagining that they might be overweightseemed to lead women to question their senseof self, even though they claimed afterwardthat the test was boring or meaningless.

Men showed no significant mPFC activationwhile processing either type of equivalentmale image.

The researchers concluded that there are‘sub-clinical’ issues with body image amonghealthy women and a much finer linebetween women with and without eatingdisorders than previously thought. The leadresearcher commented, ‘This is kind ofvalidating the suspicion that most women areteetering on the edge of an eating disorder. Ifthe brain response is so strong in theseapparently healthy women...’ (Owens, Allen &Spangler 2010).

Related findings are also reported fromHiroshima University where healthy womenand those with eating disorders werepresented with morphed images of themselvesand that of another woman. The pre-frontalcortex and the amygdala (implicated inprocessing emotional reactions such as fear,threat, anxiety and emotional responses topain) were ‘significantly activated [in] healthywomen in response to their own fat-image’.(Miyake et al, 2010)

Even the printed word elicits similarneurological reactions. The study ‘Genderdifferences in brain activity generated byunpleasant word stimuli concerning bodyimage’ found that in women, words such as

‘obesity’, ‘corpulence’ or ‘heavy’ wereaccompanied by increased activation in theamygdala, while the left mPFC (associated withdecision making and rational thought) becameinactive. In men the response was the reverse.The authors believe that the mPFC isresponsible for the gender differences in theprocessing of words concerning body image,and may also be responsible for genderdifferences in susceptibility to eating disorders.(Shirao et al, 2005)

Electronic media and eating pathologyAs visual media of thin female physiquesreaches further across the globe theneurological alterations cited above may beincreasing among large sections of apopulation and at younger ages. In a landmarkstudy, a multidisciplinary team from HarvardMedical School travelled to Fiji to evaluate theimpact of the introduction of television onbody satisfaction and disordered eating inadolescent girls. In Fiji, the ideal body weightfor females has always been very full, whilegoing thin – as Fijians refer to weight loss –is a cause for concern, not admiration. Dietinghas been rare.

In 1995 television arrived and within threeyears everything changed. The percentage ofsubjects with pathologically high scores on atest for disordered eating more than doubledfrom 12.7% to 29.2% and three-quarters of thestudy population reported that they felt ‘toobig or fat’. Dieting among teenagers whostarted to watch television increaseddramatically to include two in every three girlsand the rate of self-induced vomiting tocontrol their weight, which had been rated asnon-existent before television arrived, leapedto 11.3 per cent of that population. The girlsopenly cited thin female characters inAmerican programmes as inspirations forchanging their bodies. Comments included‘I feel fat … I just admire them. I want theirbody, I want their size’.

The researchers describe the ‘dramaticincrease’ in disordered eating. ‘The impact oftelevision appears especially profound…Western media imagery may have aprofoundly negative impact upon body imageand disordered eating attitudes andbehaviours, even in traditional societies inwhich eating disorders have been thought tobe rare’ (Becker et al, 2002).

Diet-induced biological changesA British study has found that more than onein four adults in the UK is trying to lose weight‘most of the time’ (Mintel, 2004) either due tobody dissatisfaction or genuine obesity. Yet



you cycle again.’ Weight cycling averaging only2.5kg over two-year periods among normal-weight individuals is strongly linked to ‘ahigher risk of cardiovascular disease anddeath’. (Waring et al, 2010)

Gene expressionMany genes can be up-regulated or down-regulated by changes in behaviour andenvironment, through such external epigeneticmechanisms. Nutrition and diet-inducedchanges in gene expression are nowincreasingly reported. Dahlman et al (2009)randomly assigned overweight women to amoderate-fat, moderate-carbohydrate diet or alow-fat, high-carbohydrate hypoenergetic dietfor 10 weeks. Irrespective of the type of diet,in adipose tissue ‘a total of 52 genes weresignificantly up-regulated and 44 were down-regulated as a result of the intervention.’

Tenomodulin (TNMD) is a transmembraneglycoprotein. TNMD gene expression inhuman fat tissue was down-regulated duringdiet-induced weight loss, with a 65% decreaseafter 18 weeks of dieting (Saiki et al, 2009). Inboth breast and abdominal tissue, significantlyreduced expression of genes is observed in thelipid metabolism and glycolytic pathwaysfollowing dietary energy restriction (Ong et al,2009). The chronic dieting of anorexia nervosais also accompanied by epigenetic changes inadipose tissue. Decreased body fat content ofpatients with anorexia nervosa wasaccompanied by a reduction in fat mRNAadiponectin, leptin, interleukin-6 and CD68expression, while resistin mRNA expressionwas increased. (Dolezalova et al, 2007)

But in understanding the link betweenexposure to visual media of thin femalephysiques and the onset of eating disorders, towhat extent can body dissatisfaction induceepigenetic changes which activate psychiatricdisorders such as anorexia nervosa? HarvardMedical School molecular biologistsAbdolmaleky et al (2008), examiningepigenetic alterations of the dopaminergicsystem in major psychiatric disorders, believethat ‘environmental factors can influence DNAmethylation patterns and hence alter geneexpression. Such changes can be especiallyproblematic in individuals with geneticsusceptibilities to specific diseases. Recentreports from our laboratory providedcompelling evidence that both hyper- andhypo-DNA methylation changes of theregulatory regions play critical roles in definingthe altered functionality of genes in majorpsychiatric disorders’.

Psychological distress such as child abuse isnow found to leave epigenetic marks on DNA

dieting is increasingly being found to be amajor biological event, causing significantmetabolic, neuroendocrine and epigeneticalterations, in some cases paradoxically leadingto disease.

Tomiyama et al (2010) recently reported thatrestricting calories to 1200 kcal per dayincreased the total output of cortisol infemales. Cortisol is important for regulatingfunctions such as glucose metabolism and theinflammatory process. Prolonged exposure tohigh levels, however, can lead to higher bloodpressure, suppressed thyroid function,impaired immunity, and increased intra-abdominal fat – all of which contribute tochronic disease states such as heart disease,diabetes and cancer.

The study also found that monitoringcalories increased perceived stress andconcluded: ‘Dieting may be deleterious topsychological well-being and biologicalfunctioning’. Stress has been linked to over-consumption of calorie-rich foods andconcomitant weight gain in rodents, primatesand humans. In mice Latagliata et al (2010)found that the stress of going on a diet affectsthe release of norepinephrine, which makesdieters hunt for food. The food-restricted micewere even willing to tolerate electric shocks toeat chocolate again because, through stress,‘adaptive food seeking/intake can betransformed into maladaptive behaviours’ via‘top-down’ prefrontal cortical noradrenergiccontrol over eating disturbances.

Intermittent ‘yo-yo’ dieting is increasinglypracticed in response to body dissatisfaction. Itis generally ineffective in achieving enduringweight loss and the reasons for failure arebecome clearer. Cottone et al (2009) found thatthe brains of rats alternating between healthyand sweet (unhealthy) food in the way manydieters do, showed highly significantrecruitment of neural circuits (CRF system)involved in stress reactions and promoted the‘compulsive selection’ of unhealthy food andthe undereating of healthy foods. This changein dietary preferences was accompanied by ‘awithdrawal-like state seen in drug dependence.’

Regarding the implications for the manyhumans who diet in this way, the author’s state,‘motivational processes can become perturbedin individuals who experience repeatedcontrasts in the intensity of hedonic stimuliover time. Adaptively, such processes may shiftfood-seeking and consummatory behaviortoward energy-dense, high-reward foods, whiledevaluing efforts to obtain less energy-rich,low-reward foods’. Cottone commented: ‘Thiseating pattern leads to a vicious circle. Themore you cycle this way, the more likely it is





Tonga, where big hastraditionally beenconsidered beautiful.Photo by A. Sigman.

in genes that control our stress response, whichthen increases the risk of suicide (McGowan etal, 2009). A disturbed expression ofdopaminergic genes has now been identified ineating disorders (Frieling et al, 2009). Can earlyor prolonged body dissatisfaction also leaveepigenetic marks on DNA?

Media and evolutionary adaptationStepping back from the minutiae of geneexpression, it is now possible to viewexposure to high numbers of thin mediaimages in an evolutionary context, activatingan adaptive selection mechanism anddistorting it so it becomes maladaptive.

Heterosexual human females maintain/adapttheir physical appearance in accordance withsexual dimorphism – the systematic differencein form between individuals of different sex. Infemales, more subcutaneous fat and fatdeposits mainly around the buttocks, thighsand hips are central to sexual selection. Thewaist-hip ratio of any physique is very stronglycorrelated to male perception of femaleattractiveness across all cultures andthroughout history. This is a key health andfertility indicator and core feature of femininebeauty (Singh et al, 2007).

Exposure to visual images depictingattractive females is found to alter women’sperception of their own sexual attractivenessand mating viability through a cognitivecomparison process referred to as the contrasteffect (Gutierres et al, 1999).

The contrast effect is the enhancement ordiminishment of perception, cognition andrelated performance as a result of previousexposure to a stimulus of lesser or greatervalue in the same dimension (e.g. weight,height, luminescence). Contrast effects areubiquitous throughout human and non-human

animal perception and cognition. In terms ofevaluating one’s own attractiveness, oneappears more attractive when contrasted witha person less attractive and less attractivewhen contrasted with one of greaterattractiveness. Indeed, women are most highlysatisfied with their own body image whenexposed to images of females wider thanthemselves (Tucci & Peters, 2008).

Until recently these self-evaluations of bodyattractiveness involved comparisons with arelatively small number of other women in thelocal mating pool. However, today’s culture isunique: the points of comparison provided byvisual media which women use in their self-evaluations are not only profuse andomnipresent but are demographically atypical,with no geographic relevance to the givenfemale concerned. Such images are often ofwomen of high media status. As the RoyalCollege of Psychiatrists (RCP, 2010) stated:‘There is a lack of reality-based imagery….propagating unattainable body ideals ... thenorm through extensive use of digitalenhancement or airbrushing.’

In short, from an increasingly earlier age,females today are exposed to evolutionarilynovel stimuli that deceive cognitive andneurological processes whose functiondeveloped to evaluate other females in asmall-scale local mating pool. The result is thewidespread body image distortion anddissatisfaction, reported above, and adaptivebehaviours often at odds with sexualdimorphism and sexual selection. As femalesuse atypical media physiques to establishcognitive norms as points of comparison andadapt their self-presentation accordinglythrough misguided dieting and disorderedeating, it has for many become a case of‘keeping up with the Boneses’.

Health as opposed to the Department forCulture, Media and Sport.

There is already a precedent for mediapolicy and legislation based upon thebiological characteristics of peoplerepresented on television screens, forexample, there is racial diversity and genderlegislation. The BBC, for instance, ‘iscommitted to reflecting the diversity of the UKaudience… in its output on TV, on radio andonline.’ At the same time, an ongoing issue isthe de-selection of females whose biologicalcharacteristics include grey hair and/orwrinkles on all electronic media networks inmost Western industrialised countries.Following this logic, female physique is yetanother biological parameter which could beconsidered an aspect of diversity.

Both the BMA and the RCP have called formedia physiques ‘that cover a diversity ofweight, shape, age…’ Implementing thispolicy will require a new-found enlightenedintolerance towards images deemed harmful,i.e. the incorporation and active exclusion ofmedia physiques according to their degree ofrisk to young female viewers. While mostconcern has surrounded thin fashion models,greater risk may lie in the more everydayambient images of ‘permarexic’ – visiblyunhealthily thin – children’s televisionpresenters, actresses and innocuousnewsreaders who form the backdrop to thevisual lives of girls and women. At a practicallevel, a minimum standard of riskacceptability would have to be establishedbased upon visual physique parameters suchas waist-hip ratio and dress size. Alternatively,ensuring that a roughly accurate proportionof female media images are an average UKdress size 16.

This may seem an extraordinary form ofsocial medicine but the evidence suggests that‘a lack of reality based imagery’ in media iscausing health problems in a very largenumber of women and young girls. And so itappears that while men eat food, women havea relationship with food. This relationship hasgrown increasingly dysfunctional. Forty yearsafter the debut of body politics, biology isexplaining more precisely why fat is afeminine issue.

ConclusionsThere has been a decided shift in position byscientists and prominent medical bodies inconsidering media images as being causative.Spettigue and Henderson (2004), for example,concluded: ‘The media is a causal risk factorfor body dissatisfaction, negative effect andeating pathology’.

The Royal College of Psychiatrists has issueda 'Statement on the influence of the media oneating disorders' (2010). ‘The media has a rolein both providing a social context for thedevelopment and maintenance of eatingdisorders ... achieved by propagatingunobtainable body ideals and the acceptabilityof dieting leading to lowered mood, bodydissatisfaction and eating disorder symptoms.There is a lack of reality-based imagery’.

In their ‘Summary and Call for Action’, theydemand the ‘use of role models throughout themass media that cover a diversity of weight,shape, age… cessation of the use ofunderweight models… raising awareness ofuse and extent of digital manipulation ofimages through use of a kite mark’.

There is good reason for these strongreactions as few realise the sheer prevalenceand mortality rate of anorexia nervosa. In theUK, 1.4m females currently have an eatingdisorder. Of these 140,000 have anorexia(NICE, 2004) and with a 10% mortality rate,approximately 14,000 will die. If only 5% ofthese deaths could hypothetically be attributedmainly to the effects of exposure to thin mediaphysiques, this equates to 700 deaths. This isfar greater than the number of women in theUK killed each year through domestic violence(approximately 100) or from heterosexuallycontracted HIV/AIDS (38) per annum.

A decade ago, the British MedicalAssociation’s Board of Science and Educationdemanded ‘a more responsible editorialattitude towards the depiction of extremelythin women as role models’ (BMA, 2000). Yetmatters have become much worse.Traditionally, suggestions that media imagesare causative are deflected by therationalisation that ‘the media merely reflectssociety and are being used as a scapegoat forbody dissatisfaction and eating disorders’.

However, the biological sciences have nowprovided a deeper understanding of theprecise role of media physiques in thesepathologies. In other areas of child and publichealth, exposure to causative risk factors fordisease are ultimately controlled throughlegislation. As thin media physiques are now abiologically based medical issue, it raises thequestion of whether assertive guidance shouldin future emanate from the Department of



Dr Aric Sigman FSB is a Fellow of the Royal Society ofMedicine and Associate Fellow of the British PsychologicalSociety. He was recently invited to address the EuropeanParliamentary Working Group in Brussels on ‘The Impact ofTelevision and Screen Media’ on child health and well-being.

Further reading and references can be found atwww.societyofbiology.org/biologist

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a source of thinspiration? - aric sigman

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