E STIMATING BODY - IMAGE PERCEPTIONS AND ISSUES FOR CONSIDERATION

Body image is considered a multi-dimensional construct (121,189). Assessment of body image such as body image dissatisfaction or satisfaction, body weight distortion, affective reactions, and perceptual discrepancies or discordance, therefore, requires multi-dimensional techniques (121,190). An important consideration in the assessment of body image is ensuring that the measure under consideration most appropriately measures or indexes the particular dimension of body image of interest (e.g. body image dissatisfaction or weight distortion) (121,127).

Over 40 instruments for measuring body image are documented (189–191), all of which assess body image based on four techniques: (i) figure preferences, (ii) questionnaires (123,127,129), (iii) video projection, and (iv) computer-aided measurement techniques (192–194). With figure preferences, the use of silhouettes is the most commonly used method. Using the figure preference, body image is often measured by asking participants to rate their current and ideal body shape using a series of depictions or silhouettes. The difference between these two values is the measure of body dissatisfaction. This method, however, has been indicated to be only subjective in measurng perceived weight or size.

A combination of appropriate multi-dimensional methods can help ascertain body image dimensions which are essential for health research and intervention (9,127).

Questionnaires are also commonly used for measuring body image. One example of a questionnaire is the self-reported Body Shape Questionnaire (BSQ) validated by Cooper et al. (195). Other body image questionnaires include a 9-item Multidimensional Body-Self Relations Questionnaire (MBSRQ) (196,197), Body Area Satisfaction Scale, and Body Image Distortion questionnaire (BIDQ) (196).

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With the computer-aided and video projection techniques, participants are shown a series of images flashing before them; each image is a picture of them but show either increased weight or decreased weight. The participants then self-report which of the pictures they

‘feel like’ and which of them they would most likely want to be. An example of the computer-aided body image measurement technique, is the Body-Image Assessment Software (BIAS) (194). BIAS evaluates body image distortions and body dissatisfaction via the on-screen presentation of a scale image which can be modified by the subject in its different components. This can be run on any computer with Windows and Microsoft Access and allows for data to be recorded and exported for analysis using applications data management software such as SPSS.

Many factors, such as gender, ethnicity, culture, and age, should be taken into account when measuring body image (9,127). For these reasons, setting-specific and gender-focused instruments have been developed for assessing body-image perceptions (189,190). Mciza and colleagues developed and validated the instrument for measuring body image and body weight dissatisfaction among black South African females aged >15 years (123). This instrument was shown to have a high reliability of 0.87 for the population.

2.6.2.2 Estimating body image discrepancy indexes

Pictorial and narrative constructs of body-size/shape perception have been strongly recommended for body-image studies in populations (121,127). With the pictorial construct, each cohort participant is given body image rating figures from which they are to choose the silhouette that most closely resembled how they looked (‘feel’ body image) and how they would like to look (‘ideal’ body image). The narrative constructs used structured questions related to body weight assessment. The details of body image data

collection procedures using the two constructs are explained in detail in Chapter 6 of this thesis, ‘Study design and methods’ sub-section 6.2.

This study used the (i) pictorial construct (silhouettes) to describe body-size/image perception (26,146) and (ii) narrative construct (structured questions) to describe weight perceptions (27,123). Three specific body-image dimensions, i.e. (i) body-size dissatisfaction, (ii) discordance in weight status, and (iii) perception about own weight, were considered for the study. The choice of these methods was based on their proven validity and appropriateness in measuring body-image perceptions (34,127).

2.6.2.3 Body-image estimations: inconsistent results in literature and the way forward

Studies have shown that obese and overweight African women commonly underestimate their body weight. Puaone et al. (33) reported that nearly 15% of women in an SA township community self-reported that they were normal size, whereas up to 53% of them were either overweight or obese. Mciza (34) reported that mothers and adolescent girls in South Africa underestimated their weight/sizes. Previous studies confirmed underestimation of body size among females in Kenya (10), Nigeria (198), Seychelles (146), and Ghana (145). Although studies have shown that overweight/obese women in many settings underestimated their weight, other studies have reported the contrary, especially among individuals of non-African descent. For instance, white African women and adolescents over-estimated their weight (34,133,136), but most often more African men overestimated their body sizes than the women of the same weight category (11,123,199). On the other hand, some studies documented that normal and overweight adults self-reported their perceived body weight accurately to their measured body weight (10,141,146).

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Researchers have argued the possible reasons for these conflicting results on body image self-assessment. Many believe that results of body image self-assessment would mainly depend on the instruments or methods of measurement, the setting (cultural or location), and gender and age of participants interviewed (34,127,190,196).

In this area (self-assessment of body weight/size among obese), it is difficult to summarise the literature, because there are findings to support the three different conclusions: obese individuals overestimate, underestimate and accurately estimate their body size. The inconsistent results across the literature, according to Schwartz and Brownell, are potentially because of the different methods of measurement and study samples, which vary on important dimensions (9). The differences in results could also be as a result of participants’ weight status. For example, people within a normal weight range versus people at the weight extremes, or people who are currently losing weight versus people at a stable weight as well as clinical versus community-based study participants. Socio-cultural factors may be another reason for inconsistent results across the literature with regard to over-, under- and accurate estimation of body size in obese populations (9,146,200).

Considering Schwartz and Brownell’s views, the important question is not whether average obese individuals are accurate or inaccurate in their ability to judge their body size. It is, however, what the perceived body image means to them, and how it affects their lives. Moreover, it is believed that underestimation of body size by obese women may be linked to increased self-efficacy and positive self-image (9). Findings in the olders studies such as the study by Collins et al. (1983) suggest that individuals who overestimated their body sizes were also the most likely to drop out of a weight-loss intervention (201). However, a reduction in the overestimation rate, after being enrolled

for treatment, suggests an association between self-efficacy in making healthy changes and perceiving one’s body closer to the societal norm (9,201).

From the above discussions, appropriate, evidence-based information on weight estimation that will support intervention is critical. To address the inconsistency in results, researchers strongly recommend using a homogenous sample population segregated by sex, and weight category, as well as appropriate validated body-image measurement techniques (9,34,127). This approach is lacking in many body-image studies, including those conducted in black African communities.

This thesis employed both quantitative and qualitative methods to attempt to assess body image and weight discordance efficiently, taking into consideration, the segregation of the participants by sex, weight and location.

2.6.2.4 Key issues to consider in measuring body image

The field of body image has experienced considerable growth especially in the last 40 years (127,129). Body image is a multifaceted construct consisting of a variety of measured dimensions (127), as pointed out in previous sections. For these reasons, researchers have advocated for a more consistent conceptualization of body image and the utilisation of appropriate measures in specific contexts to engender more valid comparisons across disparate body-image studies (127). For better research outcomes, it has been recommended that body-image studies should use multiple measures of components and assess the validity and reliability of such measures in their study samples (9,127). Multiple measures will help describe the many components of body image more appropriately, and reliability will support the interpretation of the findings. For this study, three body-image dimensions – body-size perception, weight discordance estimation, and

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