Mass media has been identified as an influential cause of body dissatisfaction in women [1, 2]. In recent years, social networking sites (SNS) such as Facebook, Instagram, Twitter, Tumblr, and MySpace have been the subject of much investigation to determine their positive and negative impacts on body image [3, 4]. A systematic review of 20 studies (including 16 cross-sectional and four experimental designs) showed that overall time spent on SNS is associated with body image disturbances and disordered eating . Thinspiration, or inspirational messages promoting thinness, has received criticism for its detrimental effects on body image . Existing research has analyzed thinspiration content on SNS platforms such as Facebook, MySpace, Twitter, Pinterest, and Instagram [7,8,9]. These content analyses have found that thinspiration posts feature images of extremely thin or underweight women, often in sexually suggestive poses focused on the pelvis and abdomen, and the bony features of those parts. Thinspiration content may also contain references to other mental health problems, such as depression, suicide and self-harm . Additionally, researchers  have found differences in the severity of thinspiration content between SNS and the hashtags used to identify content.
SNS have also become places to post messages and images “intended to inspire people to live healthy and fit lifestyles through motivating exercise- and diet- related images and text” . Such content is referred to as fitspiration. Researchers have begun examining the content of fitspiration on websites as well as SNS [5, 10,11,12,13,14,15,16,17], and have found that fitspiration posts emphasize appearance and attractiveness, rather than health, as motivation for engaging in fitness behaviors. Female subjects in fitspiration images are frequently thin and sexually objectified [10, 13, 17]. Additionally, Boepple et al.  found that 45% of fitspiration images included figures posed to appear thinner or smaller than reality (e.g., positioning the camera from above or tilting the hips to minimize body size). These findings suggest a problematic emphasis on thinness and physical attraction as the motivation and reward for exercise and suggest that the female body ideal has shifted to emphasize both extreme thinness and fitness. However, it is still unclear if fitspiration content warrants as much concern as thinspiration.
There is evidence that, like thinspiration, fitspiration content may be detrimental to the mental health of its users. For example, Hefner et al.  found that use of fitness-related mobile phone applications and SNS use in general were significantly associated with disordered eating and compulsive exercise behavior. In a comparison of women who posted fitspiration versus travel images on Instagram, Holland and Tiggemann  showed greater disordered eating, drive for thinness, and compulsive exercise among women who posted fitspiration images. Although fitspiration content has been shown to increase users’ intentions to improve their fitness, it also decreased body satisfaction and appearance self-esteem, and increased drive for thinness [19, 20]. These findings suggest that fitspiration content has mixed effects on users, simultaneously encouraging health in its promotion of physical exercise as well as harmful attitudes towards eating and the body. Other studies have shown that women exposed to thin-athletic models experience more body dissatisfaction than when exposed to normal-weight-athletic models, neutral objects, and even traditional thin-ideal images [21, 22]. These findings suggest that the addition of fitness to the traditional thin-ideal may have the effect of making the ideal body even more unattainable for women. Further, Homan & Tylka  found that positive effects of physical exercise on increasing body appreciation and body satisfaction were weakened when exercise was primarily motivated by a desire to change the appearance of one’s body shape or weight. Supporting a conceptual overlap between fitspiration and thinspiration content, exposure to fitspiration content on Pinterest has also been found to predict willingness to engage in extreme weight-loss tactics, such as crash dieting . Finally, a study of user engagement with online health and fitness content found that participants who also reported misuse of diet pills or other eating disorder symptoms were more likely to ‘like’ fitness-related posts on social media .
Given emerging evidence of overlap between thinspiration and fitspiration, directly comparing both types of SNS content is worthwhile to ascertain their similarities and differences. Boepple and Thompson  compared images from 50 thinspiration and 50 fitspiration websites, finding that whereas thinspiration featured a greater emphasis on weight loss and thinness, the two types of content did not differ in their emphasis on objectification, dieting, and guilt about body weight or shape. However, the images assessed were from dedicated websites, which may not be as broadly used for photo-sharing as SNS. In contrast, Talbot and colleagues  analyzed 734 thinspiration, fitspiration, and “bonespiration” (content glorifying skeletal bodies suggestive of anorexia nervosa) images on three SNS: Twitter, Instagram, and WeHeartIt. They found that thinspiration and bonespiration contained more thin, objectified bodies than fitspiration, which featured more muscular bodies. However, thinspiration and fitspiration did not differ in the frequency of bone protrusions featured in images, suggesting that it may be a subtype of fitspiration posts that is similar to thinspiration. Talbot et al.  coded images for only body type and objectification (defined as the proportion of body features visible in the image, with images focused on smaller proportions of features considered more objectifying). They did not examine the text associated with SNS image captions, such as for weight/shape guilt or dieting messages.
Although studies have examined fitspiration and thinspiration content on a variety of SNS, only one  has made direct comparisons between platforms. No study to date has compared fitspiration posts between SNS; instead, studies have analyzed fitspiration content drawn from multiple SNS together as a single group. Given that Ghaznavi and Taylor  found differences in severity of thinspiration posts between Pinterest and Twitter, it is worth examining whether any SNS differences exist in thinspiration or fitpsiration posts. There is also evidence of differences among user communities of SNS: wealthier teens are more likely to use platforms such as Twitter and Instagram than lower-income teens, and SNS emphasizing photo-sharing, such as Tumblr and Instagram, are more popular with teenage girls than boys . Similarly, to date only Ghaznavi and Taylor  have compared content between thinspiration hashtags (tags added to posts which allow users to find or follow specific types of content), and no study to date has compared fitspiration across SNS or hashtags. Comparing content between platforms and hashtags could provide a more complete picture of thinspiration and fitspiration communities on SNS, and may identify subtypes that are most harmful. Finally, most studies have examined only a few image or text-based variables among fitspiration or thinspiration content, leaving gaps in understanding the context in which users are posting images and writing accompanying text captions.
The purpose of the present study was to conduct a content analysis of fitspiration and thinspiration posts on three popular SNS—Instagram, Tumblr, and Twitter—and to examine similarities and differences between fitspiration and thinspiration content.
Based on previous findings [10, 11, 16, 17, 19, 26], we hypothesized that fitspiration would include fewer posts featuring extreme thinness (i.e. emphasizing bony features such as hip and collarbone protrusions) or references to disordered eating symptoms than thinspiration, but would emphasize weight loss, dieting and appearance-based motivations in a manner similar to thinspiration.
A secondary objective of this study was to explore possible differences in fitspiration and thinspiration posts among three SNS, as well as among main hashtags used to identify content in posts. Users may select different SNS according to the features offered (such as emphasis on photo-sharing), or what is popular among their peer group. There are also important demographic differences among users of Instagram, Tumblr and Twitter. For example, almost three-quarters of teens and young adults aged 13 to 24 have reported using Instagram, whereas Twitter and Tumblr are less widely used, with 40% and 16% of teens and young adults reporting having used the platforms respectively . We had no specific hypotheses about the direction or size of any content differences on Twitter, Tumblr and Instagram.