Body Size Satisfaction and Physical Activity Levels Among Men and Women
Abstract
Body size satisfaction may be an important factor associated with physical activity. We analyzed data from the 2002 National Physical Activity and Weight Loss Survey (NPAWLS), a population-based cross-sectional telephone survey of US adults. Multiple logistic regression models were used to examine the association of body size satisfaction on being regularly active. Participants were aged ≥18 years with complete data on weight, race/ethnicity, physical activity level, and body size satisfaction (n = 10,021). More than half of men (55.8%) and women (53.3%) who reported being very satisfied with the body size were regularly active. After adjustment for covariates, participants who reported being somewhat or not satisfied with their body size had a 13 and 44% lower odds of being regularly active, respectively, compared with those very satisfied with their body size. When stratified by race/ethnicity, this association remained in whites (P for trend <0.001), but became weaker and nonsignificant in blacks, Hispanics, or other racial/ethnic groups. Irrespective of actual weight, those who were satisfied with their body size were more likely to engage in regular physical activity than those less satisfied. Further research is needed to explore predictors of physical activity to reduce health disparities.
In western society, people are stigmatized for being overweight, which may lead to body dissatisfaction, lowered mood and self-esteem (1). Being self-conscious about one's body size may play a role in influencing a variety of health behaviors such as fruit and vegetable consumption (2) and physical activity patterns (3). The relationship between body size satisfaction and health behavior is complex, and may be influenced by a number of psychological factors such as self-esteem (4), extrinsic or intrinsic rewards (e.g., look more attractive) (5) and physical influences (e.g., fitness level) (6). Given the national concern with the increase in obesity, and possible consequence of body size dissatisfaction (7), greater attention is needed to shed light on demographic differences and behaviors which contribute to promote a healthy weight.
Limited research to date has focused on the relationship of body size satisfaction on level of physical activity. Findings from the literature indicate gender differences between men and women in how they see their bodies and this may affect how they respond to physical activity. In women, this difference is reflected in a higher concern with having a slender body (8) and in men, in terms of a higher concern with becoming physically fit and muscular (9). The role of body size satisfaction as an influencing motivator to engage in physical activity is an area for further study among men and women.
We used the National Physical Activity and Weight Loss Survey (NPAWLS) data to examine the prevalence of body size satisfaction by demographic characteristics and lifestyle physical activity, and to examine the association of body size satisfaction on being regularly active.
Research Methods and Procedures
Data source
NPAWLS is a nationwide telephone survey conducted between September and December 2002 by the University of South Carolina Prevention Research Center; research procedures were approved by the institutional review board. Respondents were drawn from the US adult population residing in telephone-equipped locations. A replicate design mixing telephone numbers from three independent samples was used to achieve target percentages for Hispanic and non-Hispanic black respondents. The sample design has been previously described (10). Respondents excluded from the sample had no telephone, were institutionalized, or lived in group quarters with 10 or more unrelated residents, or did not speak English or Spanish well enough to be interviewed. The median response rate, based on Council on American Survey Research Organizations, was 30.9% (11).
A total of 11,211 adults aged ≥18 years participated in the survey. Those with unknown body size satisfaction (n = 43), missing information on BMI (n = 812), moderate- or vigorous-intensity physical activity (n = 335) were excluded, and the final study sample consisted of 10,021 adults.
Exposure variable
Body size satisfaction was assessed by one question: “How do you feel about your body size right now?” Respondents were asked to respond using three mutually exclusive categories: very satisfied, somewhat satisfied, not satisfied.
Outcome variable
Physical activity was assessed by asking respondents about participation in moderate- or vigorous-intensity lifestyle physical activities during a usual week. Moderate intensity was defined as activities that cause small increases in breathing or heart rate (e.g., brisk walking). Those who answered “yes” were asked the frequency and duration of their activities. In a similar fashion, respondents were asked about their participation in vigorous-intensity activities, defined as activities that cause large increases in breathing or heart rate (e.g., running). From these responses, three levels of physical activity were defined: regularly active (moderate activity for ≥30 min/day on ≥5 days or vigorous activity for ≥20 min/day on ≥3 days); insufficient (some activity), and inactive (no moderate or vigorous activity) based on physical activity recommendations for adults (12).
Covariates
The demographic variables examined were sex, and self-reported measures of height in meters and weight in kilograms, from which BMI was defined as weight in kilograms divided by height in meters squared. BMI was divided into four categories (underweight, BMI <18.5; normal, BMI 18.5–24.9; overweight, BMI 25.0–29.9; obese, BMI ≥30.0) in accordance with World Health Organization guidelines (13).
Race/ethnicity was assessed by asking respondents, “Which one of these groups would you say best represents your race?” Self-reported race/ethnicity was categorized as white, black, Hispanic, and other. Any respondent who reported being of Latino ethnicity were categorized as Hispanic regardless of race.
Statistical analysis
A χ2-test was used to compare frequencies of body size satisfaction across physical activity levels and covariates. Using the very satisfied group as the referent, multiple logistic regression models were used to investigate the association of body size satisfaction on being regularly active after adjusting for age (14), sex, race/ethnicity, and BMI (15). We further tested possible interactions of body size satisfaction and observed no significant interaction with sex (P = 0.49) and a suggestive association for BMI (P = 0.05). All statistical procedures were performed using SAS (Version 9) and SUDAAN (Version 9.0).
Results
Table 1 shows that the prevalence of body size satisfaction was higher in Hispanic men and women (46.3%) as compared with whites (32.8%), blacks (31.8%), and other race/ethnicities (37.2%) (P < 0.001). The prevalence of body size satisfaction was also higher in normal-weight individuals than in overweight or obese adults. Among men, 57.4% of those who were normal weight reported being very satisfied with their body size compared to 37.6% who were overweight and 13.4% who were obese (P < 0.001). Among women, 43.7% of those who were normal weight reported being very satisfied with their body size compared to 15.3% who were overweight and 6.1% who were obese (P < 0.001).
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Men who were very satisfied with their body size were more likely to be regularly active (55.8%) than insufficiently active (31.9%) or inactive (12.3%) (P < 0.001) (data not shown). Among men who were not satisfied with their body size, significantly more fell into the insufficiently active category (43.7%) than in the regularly active (38.7%) or inactive categories (17.6%) (P < 0.001). Similarly, women who were very satisfied were more likely to be regularly active (53.3%) than insufficiently active (33.4%) or inactive (13.3%) (P < 0.001). Among women who were not satisfied with their body size, significantly more fell into the insufficiently active category (45.2%) than in the regularly active (34.7%) or inactive category (20.1%) (P < 0.001).
Table 2 shows that there was a significant association of body size satisfaction on being regularly active (P for trend <0.001). Persons who were somewhat or not satisfied with their body size had a 13 and 44% lower odds of being regularly active, respectively, as compared with persons who were very satisfied with their body size, after adjustment for covariates. We also observed a significant interaction between race and body size satisfaction (P < 0.001). After stratified by race/ethnicity, there was a significant association between body size satisfaction and being regularly active in whites (P for trend <0.001), but this relationship became nonsignificant in blacks, Hispanics, or other race/ethnicities.
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Discussion
Approximately one-third of adults were very satisfied with their body size. Our findings are consistent with the literature suggesting that men are more satisfied with their body than women (1,16). When examining the prevalence of body size satisfaction by race/ethnicity, Hispanic men and women had the highest prevalence of body size satisfaction than other racial/ethnic groups. Study findings that examine the influence of race/ethnicity on body size satisfaction are mixed, and may be related more to level of acculturation than to ethnicity alone (15). However, in a large observational study of men and women that examined body size satisfaction by four groups (black, Hispanic, Asian, and white), Cachelin et al. (14) found that after controlling for differences in age, education, and BMI, most racial/ethnic differences disappeared.
We also observed that white men and women who were somewhat or not satisfied with their body size were less likely to be regularly active, than those who were very satisfied with their body size. This association was not significant for blacks, Hispanics, or other racial/ethnic groups after adjusting for age, sex, and BMI. Although the reasons for racial/ethnic differences in being regularly active remains unclear, Crespo et al. (17) suggests that physical activity behavior may be influenced by cultural attitudes about a desirable and healthy body weight. Further research is needed to explore aspects of the body size satisfaction construct (15) because a single item of body size satisfaction does not seem to predict physical activity behavior in minority populations.
Although the NPAWLS is representative of the US population, data are cross-sectional and results should be interpreted with caution. Additionally, self-reported measures were used and the term body size satisfaction is subjective. Future work may want to examine the construct of body size satisfaction as most of the indicators have been validated on white women and may not accommodate cultural variations and language nuances. Although the extent to which body size satisfaction influences physical activity behavior is not clear, our results show that irrespective of actual weight, those who were satisfied with their body size were more likely to engage in regular physical activity than those less satisfied.
Acknowledgment
This study was supported by a Cooperative Agreement from the US Centers for Disease Control and Prevention, SIP-20-01, U48/CCU409664. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
Disclosure
The authors declared no conflict of interest.
