In addition to the content, images of women's – and, increasingly, men’s – bodies in magazines also send messages. There has been a progression towards thinner and thinner models in ads and magazines: twenty years ago, the average model weighed 8 per cent less than the average woman – but today’s models weigh 23 per cent less. 
Even these dangerously underweight models are often not seen as being thin enough by editors, who employ Photoshop and other image manipulation tools to create women who are literally "too thin to be true" – as well as to alter photos of celebrities so they meet this standard. Men in magazines are also frequently "photoshopped" to achieve the lean and muscular ideal. 
Why is there such pressure to make models increasingly thinner, to the point of erasing whole body parts?  Simply put, advertisers believe that thin models sell products. For almost a century, advertisers have appealed to – or contributed to – women's insecurities in hopes of selling them the solution.  In fact, advertising is so strongly associated with creating insecurities that when women are shown images of products such as shoes, perfume or deodorant in the context of fictional ads, they are more likely to answer negatively to questions such as "How attractive do you find yourself?" or "How satisfied are you with your body?" than if they saw the same photos in a neutral context. 
While it's well-established that seeing images of underweight women make normal or overweight women feel bad about themselves,  some recent research has found that that the conventional wisdom in the fashion and advertising worlds is wrong, and that consumers are less interested in buying products that make them feel insecure. (The same research, though, found that exposure to overweight models had a similar negative effect on women's self-esteem.) 
In recent years there have been some efforts in the magazine industry to buck the trend. For several years the Quebec magazine Coup de Pouce has consistently included full-sized women in their fashion pages and Châtelaine has pledged not to touch up photos and not to include models younger than 25 years of age. Some clothing retailers have also committed to not using underweight models, most notably Canadian retailer Jacob.  Perhaps most remarkably, in 2009 the editor of British Vogue, Alexandra Shulman, accused fashion designers of forcing magazines to hire underweight models by only providing "minuscule" outfits for photo shoots. Shulman even claimed to have ordered some of the resulting photos retouched so that the models would not look so thin.
There is resistance to change, both within and outside the industry: when the Australian magazine New Woman included a picture of a heavy-set model on its cover, it received a truckload of letters from grateful readers praising the move, but its advertisers complained and the magazine returned to featuring bone-thin models.  According to The Guardian, this response is not unusual: "the traditional reliance on so-called aspirational advertising has limited change, despite high-profile campaigns against perceived racism and the encouragement of unhealthy female physiques within modelling... While 'real' models have made their way into campaigns for a range of products in recent years, when it comes to the luxury sector the door remains shut." 
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The Taylor Research & Consulting Group, Taylor Kids Pulse: Where the Wired Things Are, as cited in Teen Media Monitor: Teen Girls, The Kaiser Family Foundation 2:1 (October 2003).
National Eating Disorders Association. National Eating Disorders Association Unveils Powerful & Provocative Ad Campaign. February 26, 2009.
 "The Complicated Art of Airbrushing Abdominals." Jezebel, October 7, 2010. <http://jezebel.com/5658169/the-complicated-art-of-creating-abdominals?tag=photoshopofhorrors>
 "May Vogue Visits The Future And The Future Is Missing A Clavicle." Jezebel, May 6, 2008. <http://jezebel.com/387701/may-vogue-visits-the-future-and-the-future-is-missing-a-clavicle>
 Copeland, Libby. "How advertisers create body anxieties women didn't know they had and then sell them the solution." Slate, April 14, 2011.
 "The Self-Activation Effect of Advertisements: Ads Can Affect Whether and How Consumers Think About the Self,” by Debra Trampe, Diederik A. Stapel and Frans W. Siero, The Journal of Consumer Research.
 Dirk Smeesters, Thomas Mussweiler, and Naomi Mandel. "The Effects of Thin and Heavy Media Images on Overweight and Underweight Consumers: Social Comparison Processes and Behavioral Implications." Journal of Consumer Research: April 2010.
 "Real curves on models don't always appeal." March 17, 2010.
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 Peter Walker. “Young, white and super skinny? We don't buy it, women tell advertisers." The Guardian, January 10, 2010.