Ideal body image for the opposite sex and its association with body mass index

Title: Ideal body image for the opposite sex and its association with Body Mass Index 1 María Eugenia Ibáñez-Zamaconaa, Alaitz Povedab, Esther Rebatoa 2 a Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and 3 Technology, University of the Basque Country (UPV/EHU), Spain 4 b Department of Clinical Sciences, Lund University (LU), Sweden 5 6 Corresponding author: Dr. María Eugenia Ibáñez-Zamacona. 7 Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and 8 Technology, University of the Basque Country (UPV/EHU), PO Box. 644, 48080 Bilbao (Spain). 9 Tel.: +34 94 601 5405. E-mail address: mariaeugenia.i[email protected] 10 11 Key words: Body image; Age; Sex; Nutritional status. 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Ibáñez-Zamacona ME, Poveda A, Rebato E. Ideal body image for the opposite sex and its association with body mass index. Journal of Biosocial Science. 2023;55(1):190-198. This article has been published in a revised form in Journal of Biosocial Science http://doi.org/10.1017/S0021932021000705. This version is published under a Creative Commons CC BY-NC-ND licence. No commercial re-distribution or re-use allowed. Derivative works cannot be distributed. © 2021 The Author(s). Published by Cambridge University Press . 1 Abstract 29 This research studied the preferences reported by women and men about their ideal body image for 30 the opposite sex (IBIOS), and its association with Body Mass Index (BMI). It also analyses the 31 preferences of each sex for a woman ideal body image (W-IBI) or a man ideal body image (M-IBI). 32 450 participants (18-70 years) with different weights were studied. IBIOS was assessed using 33 standard figural stimuli. The sample was divided in four groups by sex and age (<45 years; ≥45 34 years). Sex and age differences for IBIOS as well as sex differences in the preferences for a woman 35 ideal body image (W-IBI) and a man ideal body image (M-IBI) were tested using a non-parametric 36 Mann-Whitney U test. The association between IBIOS and BMI was analysed using Spearman 37 correlation. In all groups, the most chosen silhouette as IBIOS was number 4. In the under 45 years 38 group, women chose bigger silhouettes for the opposite sex than men did (p<0.05). In this age group 39 women chose as ideal smaller silhouettes for the female body than men did (p<0.01). In addition, 40 women and men in the younger age group and with normal weight chose smaller silhouettes, while 41 those with overweight or obesity selected larger silhouettes (p<0.001). Age was a relevant factor in 42 IBIOS preferences, and in the association between this variable (IBIOS) and nutritional status (BMI), 43 which was only observed in the younger age group. 44 Introduction 45 The image we have of our own body (and of the body of others) is influenced by intrinsic factors (age, 46 sex, weight, ethnicity, personality, etc.) as well as by extrinsic ones (cultural norms, family, peers, 47 both traditional and new media exposure, etc.). Body image is a complex and dynamic concept that 48 includes beliefs about appearance, feelings about the body size and shape, and perception of the body 49 (Cash & Pruzinsky, 2004). Roy and Payette (2012) consider body image as “a physiological entity but 50 also as a psychosocial construct, formed by four dimensions that combine in multiple ways: 51 attitudinal/emotional, perceptual, behavioural and cognitive”. 52 In contemporary societies, body image concerns have increased remarkably due to their relationship 53 with both eating (i.e. anorexia and bulimia) and weight disorders (i.e. obesity), anxiety and depression. 54 There is a profuse literature on body image, mostly focused on adolescence (e.g. Cohelo et al., 2016; 55 Solomon-Krakus et al., 2017), a period of remarkable biological and psychological changes, and 56 social vulnerability. However, interest and concern for body image are not exclusive of youth, and 57 extend throughout adulthood and later years (Baker & Gringart, 2009; Mellor et al., 2010). Some 58 studies show that many adults and older people are very concerned about their body image (see 59 Mariano da Rocha & Terra, 2013), especially women (Sabik, 2015, 2017; Smith Kilpela et al., 2015). 60 Adulthood is considered a fairly stable period in psychosocial terms, although there are many physical 61 and mental changes related to ageing as age advances. At physiological level, changes occur in the 62 amount and distribution of body fat, which modify body morphology and weight status; this can be 63 2 troubling especially for women after menopause. According to Chrisler and Ghiz (1993) “body 64 changes linked to menopause can change the way a woman thinks and feels about her body”. In men, 65 biological changes are more progressive and body image seems less affected than in women, although 66 there is no consensus on the matter (see Tiggemann, 2004; Davison & McCabe, 2005; Peat et al., 67 2008). 68 Through the use of validated silhouettes and other methodologies (measuring scales, questionnaires, 69 etc.), many authors have studied body image, including ideal body image (IBI) across various age 70 groups, especially in children and adolescents (Voelker et al., 2015; Neves et al., 2017) but also in 71 young, middle and older adults (e.g. Rand & Wright, 2000; Bibiloni et al., 2017; Ibáñez-Zamacona et 72 al., 2020; Stagi et al., 2021). Ideal body image preferences for the opposite sex (IBIOS) have also 73 been studied, although there is less literature on this subject (e.g. Fallon & Rozin, 1985; Gleaves et al., 74 2000; Jones et al., 2007; Maruf et al., 2012). Regarding ideal body image (IBI), girls and women 75 from Western countries generally desire smaller bodies for themselves than boys and men, who prefer 76 larger/mesomorphic ones (Tiggemann, 2004; Thompson & Cafri, 2007; Blashill & Wilhelm, 2014). 77 Discrepancies between perceived and ideal body image can lead to body image dissatisfaction and 78 low self-esteem in both sexes. In relation to this, it is important to point out that “…evaluations 79 individuals make of their bodies are related to the evaluations that they expect others may make” 80 (Davison & McCabe, 2005), which raises the interest on knowing the ideal body image that each sex 81 has of the opposite sex. In this context, Jones et al. (2007), in a study of ethnically diverse rural 82 adolescents, have shown that both African American and Caucasian men selected larger female 83 figures as ideal than the female figures selected by women; while women reported ideal male figures 84 rating similar than the ones reported by males for themselves. However, Gleaves et al. (2000) have 85 found that American and Spanish women prefer larger bodies as IBIOS than the bodies that men 86 thought women would choose; this tendency is the opposite of that observed by Fallon and Rozin 87 (1985). The two above-mentioned authors have pointed out that the differences between women and 88 men with respect to IBIOS were associated to ethnicity and socio-economic level, that is, the choice 89 was culturally based. 90 Body weight is associated with health status, physical activity, body image, and self-evaluation 91 (Olmsted & McFarlane, 2004), and their impact on body image is especially relevant in overweight 92 and obese people (Schwartz & Brownell, 2004), whose image differs from the cultural ideals in many 93 societies. For example, Sarwer et al. (2005) have observed that middle-aged women, with overweight 94 or obesity, show great concern because their body image is not ideal for Western populations. In 95 addition to physical problems stemming from weight status, this concern linked to the “perceived 96 body image” can influence interpersonal relationships and quality of life. However, it is not 97 uncommon to observe a certain degree of dissatisfaction with body size among individuals of normal 98 weight, especially among young women (Rodin et al., 1984), but also in men; this is considered a 99 3 “cultural stereotype” in both sexes (Tantleff-Dunn et al., 2011). It is of interest to take into account 100 this biological variable (i.e., weight status) in body image studies because of their implication on body 101 image disturbances (Stagi et al., 2021). The authors of this paper aim to increase the knowledge on 102 this field in the Basque Country area (Spain), and hypothesize that Body Mass Index (BMI), a 103 measure for indicating nutritional status in adults, may influence IBIOS selection. Therefore, the 104 objectives of this research were: i) to study differences between sexes and age group in IBIOS 105 preferences, ii) to examine men and women preferences for the same sex body image and iii) to 106 analyse the possible association between IBIOS and nutritional status (BMI). 107 Methods 108 Sample 109 227 women and 178 men resident in the Basque Country (Spain), aged between 18 and 70 years, were 110 studied. Their nutritional status ranged from normal weight to morbid obesity. A more exhaustive 111 description of the sample is available on a previous research carried out by Ibáñez-Zamacona et al. 112 (2020). The study has been accomplished in accordance with Helsinki Declaration; a written informed 113 consent was obtained from all participants, and the study protocols were approved by the Ethics 114 Committee for Human Research of the University of the Basque Country (UPV/EHU). 115 Anthropometry 116 Anthropometric measurements (height in cm, and body weight in kg) were taken following standard 117 anthropometric techniques (Lohman et al., 1988) by the same investigator (M.E.I-Z) in order to avoid 118 inter-observer variability. Nutritional status was estimated using BMI, calculated as weight in 119 kilograms divided by the square of the height in meters (kg/m2). The considered cut of points were the 120 established by the WHO: underweight: BMI<18.5 kg/m2; normal weight: BMI=18.5-24.9 kg/m2; 121 overweight: BMI=25-29.9 kg/m2; obesity: BMI≥30-39.9 kg/m2 (WHO, 2000). 122 Body image 123 The most attractive body image for the opposite sex (IBIOS) was assessed using the figural scale 124 developed by Stunkard et al. (1983). This validated scale consists of nine silhouettes for each sex that 125 range from very thin bodies (silhouette 1) to very large ones (silhouette 9), representing increments in 126 the weight percentage. The correspondence between these silhouettes, BMI and weight was 127 established by Bulik et al. (2001) in a large Caucasian population sample. This instrument allows the 128 measurement of the body image in a reliable and simple way and is effective in classifying individuals 129 as average/under, overweight, and obese in populations with different ethnicity, socioeconomic status, 130 sex and age (see Maupin & Hruschka, 2014; López Sánchez et al., 2018). 131 IBIOS was obtained by asking individuals to identify the figure that best represents their body image 132 preferences (“the ideal body image” or IBI) for the opposite sex. Women and men preferences for the 133 4 same sex body image (woman ideal body image (W-IBI) or man ideal body image (M-IBI)) were also 134 analysed. 135 Data analysis 136 The sample was divided in four groups by sex and age (<45 years, young adulthood; ≥45 years, 137 middle/old adulthood). The cut-off point (45 years) was based on the onset of menopause in women 138 in developed countries (the median age of natural menopause in Spain was estimated around 51.7 139 years, see Reynolds & Makhlouf Obermeyer, 2005), which when it occurs between 45-55 years is 140 considered natural and is a normal part of aging. 141 Sex and age differences in IBIOS were tested using a non-parametric Mann-Whitney U test for 142 ordinal data. In addition, using the ideal body image (IBI) previously studied in Ibáñez-Zamacona et 143 al. (2020), comparisons between women and men preferences for both woman and man images (W144 IBI and M-IBI, respectively) were made using the same test. The associations between IBIOS and 145 BMI were tested using Spearman correlation analysis. Silhouettes with frequencies under 10% were 146 excluded from the association analyses because of their low representation. All analyses were 147 performed in SPSS 23.0 statistical package (SPSS Inc., Chicago, IL). Statistical significance was 148 considered at p<0.05. 149 Results 150 As shown in Figure 1, near half of the sample in each sex and age group considers silhouette number 151 4 to be the most attractive or ideal for the opposite sex (women: 56.3% in the group under 45 years, 152 and 46% in the older age group; men: 67.4% and 57.5% in the younger and older group, respectively). 153 Differences by age are not significant. The next silhouette more frequently chosen as IBIOS by 154 women is silhouette number 5 and by men, number 3. No woman chooses larger silhouettes than 155 number 5 as the most attractive for men, and no man chooses silhouettes higher than number 6 for 156 women. Significant differences in IBIOS are detected by sex in young adults (p=0.014), but not in 157 middle and old adults. 158 The comparisons of women and men preferences for the same sex body image (woman ideal body 159 image (W-IBI) or man ideal body image (M-IBI)) only show differences for W-IBI in the younger 160 group (p=0.004) (Figure 2). Women choose as ideal figures smaller silhouettes for a woman body 161 than men do. 162 Nutritional status (BMI) and IBIOS are significantly associated in women and men under 45 years of 163 age (p=9.6E-5 and p=6.7E-5, respectively) but no significant associations are found in the older age 164 group; older participants choose IBIOS regardless of their own BMI (Figure 3). 165 166 167 5 Discussion 168 The choices of “others” about our body are relevant not only at young ages, but also in the adulthood; 169 they can cause dissatisfaction and a loss of self-esteem, and lead to physical and psychological 170 alterations, and social isolation, even at older ages (Baker & Gringart, 2009; Slevec & Tiggemann, 171 2011). The present research considers the preferences reported by a sample of adult women and men 172 living in the Basque Country (Spain) about their body image preferences for the opposite sex (IBIOS), 173 and its relation with weight/nutritional status (BMI). As well as it considers the preferences for the 174 same sex ideal body image (W-IBI and M-IBI). 175 The morphological changes that occur during ageing, together with the modification of roles and 176 social position that takes place during this process, could lead us to think that adults of different ages 177 have different perceptions and preferences about the opposite sex and, consequently, will choose 178 different images as IBIOS. However, in our sample IBIOS was essentially the same in young and in 179 older adults. Western cultures value the ideal of feminine thinness, but also that of youth, putting both 180 on the same level (Smith Kilpela et al., 2015). Thus, it is possible that similar IBIOS was chosen 181 regardless of age. On the other hand, IBIOS showed a different tendency according to sex: women 182 preferred slightly larger body sizes for men than what men preferred for women. Women of both age 183 groups preferred silhouettes 4 and 5 as the ideal body image for a man. According to Bulick et al. 184 (2001), silhouette 4 is in the upper range of normal weight (approx. BMI=23.3 kg/m2, younger group; 185 approx. BMI=23.9 kg/m2, older group), and silhouette 5 is in the lower range of overweight (approx. 186 BMI=25.5 kg/m2, younger group; approx. BMI=25.7 kg/m2, older group). These observations could 187 point to a preference for “muscular bodies” rather than an increase in body fat; however, although the 188 silhouettes used are related to a progressive increase in weight and BMI, they do not allow us to 189 distinguish between fat and lean mass from the total weight. Notwithstanding this, the recent study 190 performed by Stagi et al. (2021) in a sample of young, middle-aged and elderly adults, using specific 191 bioelectrical impedance vector analysis (BIVAsp) and Williamson silhouettes (Williamson et al., 192 2020), has shown that the silhouettes used to assess current body size perception are strongly related 193 to body fat, so the interpretation of body preferences (i.e., a larger size in the sense of muscularity or 194 fatness, or even both) remains unresolved. 195 The ideal body images that men prefer for a woman are mostly silhouettes 4 and 3 in both age groups, 196 corresponding to a normal weight (for silhouette 3: approx. BMI=20.5 kg/m2, younger group; approx. 197 BMI=21.2 kg/m2, older group; for silhouette 4: approx. BMI=22.6 kg/m2, younger group; approx. 198 BMI=23.2 kg/m2, older group). This tendency exists in both age groups, although it was statistically 199 significant only in participants under 45 years, possibly due to a relaxation of social pressure at older 200 ages (Tunaley et al., 1999). Even though the ages and ethnicity were not strictly comparable, our 201 results were quite similar to observed by Maruf et al. (2012) in Nigerian women and men, where the 202 majority of individuals considered normal weight as ideal for the opposite sex. In agreement with the 203 6 study of Laus et al. (2015) in Brazilian women and men over 18 years, in our sample the most chosen 204 silhouettes as IBIOS by women were also the most chosen silhouettes as IBI by men and vice versa 205 (results regarding IBI shown in Ibáñez-Zamacona et al., 2020). This means that both women and men 206 prefer smaller body images for a woman body and relatively larger body images for a man body. This 207 pattern is common in many populations (Barrett & Huffman, 2011; Zaccagni et al., 2014), according 208 to the socially prescribed appearance of each sex (see Calogero & Thompsom, 2010) and linked in 209 part to socio-cultural pressure, such as social networks (Anixiadis et al., 2019) or TV (Jucker et al., 210 2017). Thinness is usually linked to the ideal of beauty in women (Levine & Piran, 2004) whereas in 211 men larger images are linked to the ideal of musculature (Pope et al., 2000; Blashill & Wilhelm, 212 2014). However, significant sex differences were observed for W-IBI in the younger group, women 213 chose as ideal smaller silhouettes for female bodies than men do. 214 According to the “theory of social comparison”, individuals compare their opinions with those of 215 other individuals (Festinger, 1954). In this framework, what a person believes the opposite sex would 216 choose as the most attractive body influences the choice of the ideal self-image, especially in the 217 reproductive ages (in our sample individuals under the age of 45), when individuals start to seriously 218 consider their possible partners. In fact, as stated by Little and Perrett (2002), many of our current 219 preferences for a particular appearance may reflect evolutionary adaptations related to mate choice. 220 Some authors have pointed out that women think men are attracted to smaller, thinner women, which 221 does not generally coincide with male preferences (Bergstrom et al., 2004; Grossbard et al., 2011). 222 This “misperception” in the preferences of the opposite sex could support our results in the younger 223 group for W-IBI. However, in this age group, there was not a sexual difference for M-IBI, but a 224 tendency toward bigger bodies preferred by men can be appreciated. According to Hildebrandt and 225 Walker (2006), men accurately identified the men’s body image most attractive to women but they 226 also found that men preferred a more leaner and muscular body than what they believe women do. 227 Although the aforementioned study performed by Stagi et al. (2001) shows a positive association 228 between silhouettes and fat mass, the inadequacy of silhouettes to distinguish between fat and lean 229 mass (Coelho et al., 2015) can influence the found results. Besides that, in the middle/old adults group 230 there was a great concordance between what each sex considered W-IBI, and what they considered 231 M-IBI. Some authors have found that the misperception in relation to what the other sex consider 232 attractive is greater in young individuals (<30 years) than in older ones (Demarest & Allen, 2000), 233 which may explain our results. 234 Obesity is a global nutrition problem in developed countries, where its citizens live in contradiction 235 between the desire to be thin and the growing “fattening” of populations, often immersed in 236 “obesogenic environments” (Swinburn et al., 1999). This situation can cause multiple problems 237 related to body image such as body dissatisfaction or eating problems. Understanding the relationship 238 between body image (body size perceptions and preferences) and weight status could improve both, 239 7 obesity prevention programs and body image satisfaction. The participants in the present study share 240 the same origin and socio-economic level and, in a general way, they are equally exposed to the 241 extrinsic factors that usually influence ideal body image (media, fashion…). However, some studied 242 groups did not share the preferences for IBIOS. As initially hypothesized, in the younger groups (<45 243 years) there was a positive relation between BMI and the choice of IBIOS. Thus, women and men 244 with higher BMIs chose as IBIOS silhouettes indicative of a larger size while participants with lower 245 BMIs chose silhouettes representing smaller body sizes. Although the methodology used is not the 246 same than in the present research, Maruf et al. (2012) have also observed different IBIOS preferences 247 in relation to weight in a sample of Nigerian women and men, aged 21-29 years. 248 In conclusion, age can be considered an important factor in IBIOS preferences and in the association 249 between this variable and nutritional status (BMI). In women and men of all ages, the silhouettes 250 chosen as IBIOS were located within the normal weight, although some sexual differences were 251 relevant in younger individuals, where women chose relatively larger silhouettes for men and men 252 preferred smaller silhouettes for women. Besides, only in younger individuals women and men had 253 different preferences for a woman body. It is also in this age group where there were significant and 254 positive associations between IBIOS and weight status (BMI). Participants with a lower BMI chose 255 smaller silhouettes, while those who were overweight or obese selected larger silhouettes. Older 256 people chose IBIOS regardless of their own BMI. 257 This exploratory study has some limitations and strengths. Firstly, the sample size may influence the 258 power of the statistical analyses but the sample is highly homogeneous in terms of origin and social 259 status. Secondly, the results are specific for this sample, although they are fairly consistent with 260 observations made in other populations. An important strength of the research is the inclusion of 261 middle and older adults of both sexes, usually underrepresented in works considering IBIOS, as well 262 as the good representation of participants with different weight status (BMI), especially with obesity. 263 Ethical Approval. The authors assert that all procedures contributing to this work comply with the 264 ethical standards of the relevant national and institutional committees on human experimentation and 265 with the Helsinki Declaration of 1975, as revised in 2008. 266 Conflicts of Interest. The authors have no conflicts of interest to declare. 267 Funding: This work was supported by the Spanish Ministry of Science and Innovation (MICINN) 268 under the Grant number GCL2010-15511, and by the University of the Basque Country by a pre269 doctoral Grant number PIF09049. The last author is member of the UPV/EHU-Basque System 270 Research Group IT1380-19. 271 272 273 8 References 274 Anixiadis F, Wertheim EH, Rodgers R and Caruana B (2019) Effects of thin-ideal instagram 275 images: The roles of appearance comparisons, internalization of the thin ideal and critical media 276 processing. Body Image 31, 181–190. 277 Baker L and Gringart E (2009) Body image and self-esteem in older adulthood. Ageing and Society 278 29(6), 977–995. 279 Barrett SC and Huffman FG (2011) Comparison of self-perceived weight and desired weight versus 280 actual body mass index among adolescents in Jamaica. 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