Background: Obesity is rapidly globally increasing. Meanwhile, there is an increase in negative perception of the body image and, consequently, an increase in weight control management. Body perception plays an important mediating role between overweight or obesity and weight control behaviours. This study aims to examine whether body perception is associated with dietary weight management behaviours among Chinese children and adolescents. Methods: Child body perception and health behaviours from Chinese Health and Nutrition Survey (2015) were assessed, and 729 boys and 640 girls who aged 6 to 17 years were included in this study. Variables assessed as covariates were sociodemographic, physical activity and body perception involving self-perceptive weight status and body image dissatisfaction (BID). Multivariate logistic regression was used to explore the association between dietary weight management behaviours and body perception. Results: 60.77% students rightly matched their body mass index (BMI) with self-perceived weight. The prevalence of BID was 59.39%. After adjustment for sociodemographic information, physical activities and BMI, those whose self-perceived weight status as overweight/obesity were associated with an increased risk of dietary weight management behaviours comparing to those who have normal weight in boys (OR = 5.07; 95% CI = 1.86, 13.87; P < 0.001) and girls (OR = 14.28; 95%CI = 5.73, 35.56; P < 0.001). And those who desire to be thinner were strongly associated with dietary weight management behaviours (OR = 9.51; 95%CI = 3.47, 26.09; P < 0.001) comparing to those who were satisfied with their body image in girls. Conclusions: The results revealed that body perception had a significant association with dietary weight management behaviours and exited the discrepancy according to sex. It is necessary to promote healthy awareness of body perception and to establish self-motivation for improving basic health knowledge in school health education activities.
Keywords: Dietary behaviours; Overweight; Obesity; Body perception; Body image dissatisfaction; Weight management behaviours
Obesity is rapidly increasing worldwide and, particularly, in children and adolescents of developing countries [[
Body perception is a complex feeling involving self-perception on weight and body shape, surrounded by the sensations and immediate experiences, also involving a subjective component that refers to individual satisfaction with body size and weight [[
Although the specific route is not clear, it has been suggested that body perception may possess both direct and indirect associations with BMI, and dietary weight management behaviours. From one aspect, individual with a higher BMI increase the risk of BID and, subsequently, are more likely to adopt dietary management behaviours [[
In recent years, the prevalence of overweight/obesity of children and adolescents has generally been increased in China. More and more pupils begun to pay attention to their body shape because of the "thinness is beauty" of mainstream under media's coverage [[
Increasing prevalence of negative perception of the body image was reported in Chinese children, with more rapid increases of taking weight management behaviours in adolescents, as well as in girls versus boys [[
This current cross-sectional study employed a secondary-analyses of data from the China Health and Nutrition Survey (CHNS) in 2015. CHNS was an open prospective cohort study that collected 10 waves of measurements on geography, economic development, public resources, and health indicators in China between 1989 and 2015 [[
All children and adolescents aged 6–17 years in households which attended the CHNS were interviewed face-to-face by trained interviewers at the participants' home. Children under the age of 10 years completed the questionnaire with the assistance of their mothers or other key healthcare providers [[
Using a body composition monitor scale BC601 (TANITA, Tokyo, Japan) or a portable wall-mounted metal tape SECA206 (SECA, Hangzhou, China) respectively, participants' weight and height were measured to the nearest 0.1 kg and 0.1 m in light indoor clothing and without shoes by trained and certified staff during the detailed physical examination [[
For data analysis, BMI was classified by underweight, normal and overweight/obesity. Obesity and overweight were defined using the Working Group on Obesity in China (WGOC) age-sex-specific BMI cut-offs [[
All children and adolescents were required to answer the question as "what do you think of your current weight status: underweight, normal or overweight/obesity".
All participants were required to evaluate their figure by using the Figure Rating Scale (FRS). The scale consists of 9 contours, ranging from very thin (assignment of 1) to very obesity (assignment of 9) [[
BID variable was obtained by subtracting the participant's ideal body FRS score from the present body FRS score. BID score ≥ 1 means that the participant "desired to be thinner"; BID score ≤ -1 demonstrates that the participant "desired to be heavier"; a BID score of zero means that the participant was satisfied with his or her figure [[
All children and adolescents were asked to report if they had tried to manage their weight through diet during the previous 12 months as follows: "no, I did not", "yes, tried to lose weight" and "yes, tried to gain weight".
We collected information on age, education level (elementary school and below, junior high school, high school and above), residence (urban, rural), parents' education level (elementary school and below, junior high school, high school and above), sex (boys, girls), physical activities (no, regularly), and per capita household income (low, middle, high) through CHNS (2015) questionnaires.
The skewness and kurtosis test for normality were performed on continuous variables, and the data were normally distributed if the p-values of both skewness and kurtosis test were greater than 0.05, otherwise, the data were skewed. Continuous variables of normal distribution are presented as mean ± standard deviation, such as age and BMI. No skewness distribution data observed in this study. Moreover, categorical variable such as sex, education level, residence, per capita household income, parental education level, and physical activity were described by frequency and percentage. The chi-square tests were used to compare the sex differences for categorical variables and the t-test was used to compare the difference in continuous data. If the expected value of a data grid is less than 5, we used the Fisher exact probability method for the test.
Consistency between participants' actual weight status and self-perceptive weight status was assessed by the Kappa test. Weighted Kappa coefficients (criterion validity) were interpreted according to Landis and Koch for strength of agreement: Kappa < 0.20: poor agreement; Kappa = 0.21–0.40: fair agreement; Kappa = 0.41–0.60: moderate agreement; Kappa = 0.61–0.80: good agreement; and Kappa = 0.81–100: perfect/very good [[
Multivariate logistic regression analyses were performed to determine the association of the following outcomes behaviours with body perception stratifying by sex: dietary weight management (0 = no behaviours, 1 = behaviours). Multivariable model 1 was adjusted for age (continuous). Multivariable model 2 was further adjusted for residence (0 = urban, 1 = rural), per capita household income (0 = low level, 1 = middle level, 2 = high level), education level (0 = elementary school and below, 1 = junior high school, 2 = high school and above), mother's education level (0 = elementary school and below, 1 = junior high school, 2 = high school and above), father's education level (0 = elementary school and below, 1 = junior high school, 2 = high school and above), and physical activity (0 = no, 1 = regular). The model 3 was further adjusted for BMI (0 = normal, 1 = underweight, 2 = overweight/obesity).
All statistical analyses were performed by using STATA 15.0 (StataCorp., College Station, TX). Statistical significance was set as P < 0.05 and all statistical tests of hypothesis were two sided. All methods were performed in accordance with the relevant guidelines and regulations.
This study included 1369 children and adolescents that aged 6–17 years from urban (33.97%) and rural (66.03%) areas in China. Boys accounted for 53.25% and girls accounted for 46.75% among the participants. The mean age was 10.37 years (10.38 and 10.37 years for boys and girls, respectively). Most of the participants were elementary school students and below (68.81%). Compared with girls, boys have higher BMI (P < 0.05). There was no sex difference in distributions of other sociodemographic variables and physical activity (Table 1).
Table 1 Characteristics of Children and Adolescents According to Sex in the CHNS (2015)
Characteristics Total ( Boys ( Girls ( 17.86 ± 3.31 18.08 ± 3.39 17.61 ± 3.20 10.37 ± 3.12 10.38 ± 3.18 10.37 ± 3.06 0.932 0.491 Elementary school and below 942 (68.81) 499 (68.45) 443 (69.22) Junior high school 312 (22.79) 174 (23.87) 138 (21.56) High school and above 109 (7.96) 54 (7.41) 55 (8.59) 0.119 Urban 465 (33.97) 234 (32.10) 231 (36.09) Rural 904 (66.03) 495 (67.90) 409 (63.91) 0.203 Low income 447 (32.65) 225 (30.86) 222 (34.69) Middle income 456 (33.31) 242 (33.20) 214 (33.44) High income 466 (34.04) 262 (35.94) 204 (31.87) 0.510 Elementary school and below 132 (9.64) 66 (9.10) 66 (10.31) Junior high school 433 (31.63) 241 (33.10) 192 (30.00) High school and above 436 (31.85) 234 (32.10) 202 (31.56) 0.622 Elementary school and below 196 (14.32) 98 (13.44) 98 (15.31) Junior high school 466 (34.04) 251 (34.43) 215 (33.59) High school and above 405 (29.58) 209 (28.67) 196 (30.63) 0.126 No 830 (60.63) 427 (58.57) 403 (62.97) Regular 526 (38.42) 293 (40.19) 233 (36.41)
Note: The chi-square tests were used to examine significant sex difference in terms of grade, parental education level, residential area, per capita household income and physical activity. The t-test was used to examine significant sex difference in terms of age and BMI. Value is mean ± SD or N (%). Proportions are column percentages.
The finding showed that the prevalence of overweight/obesity was 26.95%. However, only 12.09% participants self-perceived weight status as overweight/obesity. Additionally, the majority of participants (71.76%) self-assessed their weight as normal status. The prevalence of children and adolescents dissatisfied with their body image was 59.39% (Table 2). Table 2 also presents that, regarding to the sample's characteristics, there have differences in the distribution of BMI among different sex, mothers' education levels, fathers' education levels, and per capita household income levels. Besides, we found difference of distribution of self-perceptive weight status which were manifested in residential, parental education levels, and per capita household income levels. Furthermore, the differences in the distribution of BID in grade, residence, parents' education level, and per capita household income were statistically significant.
Table 2 Comparison of distribution of BMI, self-perceptive weight and BID of children and adolescents aged 6–17 years with different sociological characteristics (N = 1,369, (%))
Characteristics BMI Self-perceptive weight BID Normal Underweight Overweight/Obesity Normal Underweight Overweight/Obesity Satisfied Desire to be heavier Desire to be thinner Boys 467(64.06) 53(7.27) 209(28.67) 0.160 520(71.33) 119(16.32) 90(12.35) 0.826 292(40.05) 266(36.49) 171(23.46) 0.317 Girls 420(65.63) 60(9.38) 160(25.00) 466(72.81) 100(15.63) 74(11.56) 264(41.25) 210(32.81) 166(25.94) Elementary school 557(59.13) 85(9.02) 300(31.85) 681(72.29) 159(16.88) 102(10.83) 0.129 366(38.85) 356(37.79) 220(23.35) Middle school 235(75.32) 24(7.69) 53(16.99) 223(71.47) 47(15.06) 42(13.46) 135(43.27) 93(29.81) 84(26.92) Junior school 90(82.57) 4(3.67) 15(13.76) 76(69.72) 13(11.93) 20(18.35) 54(49.54) 23(21.10) 32(29.36) Urban 301(64.73) 28(6.02) 136(29.25) 0.065 333(71.61) 62(13.33) 70(15.05) 223(47.96) 120(25.81) 122(26.24) Rural 586(64.82) 85(9.40) 233(25.77) 653(72.23) 157(17.37) 94(10.40) 333(36.84) 356(39.38) 215(23.78) Elementary school 131(66.84) 20(10.20) 45(22.96) 142(72.45) 38(19.39) 16(8.16) 75(38.27) 71(36.22) 50(25.51) Middle school 296(63.52) 47(10.09) 123(26.39) 327(70.17) 82(17.60) 57(12.23) 175(37.55) 191(40.99) 100(21.46) Junior school 256(63.21) 19(4.69) 130(32.10) 285(70.37) 51(12.59) 69(17.04) 182(44.94) 109(26.91) 114(28.15) Elementary school 88(66.67) 19(14.39) 25(18.94) 85(64.39) 36(27.27) 11(8.33) 47(35.61) 51(38.64) 34(25.76) Middle school 278(64.20) 48(11.09) 107(24.71) 308(71.13) 77(17.78) 48(11.09) 169(39.03) 171(39.49) 93(21.48) Junior school 266(61.01) 20(4.59) 150(34.40) 318(72.94) 44(10.09) 74(16.97) 186(42.66) 132(30.28) 118(27.06) Low 302(67.56) 50(11.19) 95(21.25) 318(71.14) 92(20.58) 37(8.28) 174(38.93) 178(39.82) 95(21.25) Middle 303(66.45) 40(8.77) 113(24.78) 322(70.61) 79(17.32) 55(12.06) 186(40.79) 161(35.31) 109(23.90) High 282(60.52) 23(4.94) 161(34.55) 346(74.25) 48(10.30) 72(15.45) 196(42.06) 137(29.40) 133(28.54) No 531(63.98) 79(9.52) 220(26.51) 0.137 585(70.48) 144(17.35) 101(12.17) 0.302 333(40.12) 294(35.42) 203(24.46) 0.627 Regular 345(65.59) 34(6.46) 147(27.95) 388(73.76) 75(14.26) 63(11.98) 221(42.02) 173(32.89) 132(25.10) 887(64.79) 113(8.26) 369(26.95) 986(71.76) 219(16.15) 164(12.09) 556(40.61) 476(34.77) 337(24.62)
Note: The chi-square tests were used to examine difference of distribution of BMI self-perceived weight and BID in terms of sex, grade, parental education level, residential area, per capita household income and physical activity. Value is N (%). Proportions are row percentages.
Approximately 60% students rightly matched their BMI category with self-perceived weight status (Fig. 1). Girls prefer to over-estimated their weight status compared to boys (11.56% vs 7.13%). Additionally, boys perceived more accurately their own weight status (62.28% vs 59.06%, P < 0.05). There was a significant, strong discrepancy between self-perceptive weight status and actual weight status (P < 0.05), as shown in Table 3. The level of agreement between self-perceptive weight status and actual weight status was poor (Kappa = 0.1960) for the total sample, and boys' Kappa values (Kappa = 0.2391) were higher than girls' (Kappa = 0.1447, Table 3).
Graph: Fig. 1 Consistency of self-perceived weight status and actual weight status (BMI) according to sex among children and adolescents aged 6 to 17 years in the CHNS, 2015 (N = 1,369). The chi-square tests were used to examine agreement between self-perceived weight status and actual weight status. If the participants self-perceived weight status corresponded with their weight status, they were classified into the consistent assessment group. If the participants self-perceived weight status was below their weight status, they were classified into the underestimated group. Otherwise, they were classified into the overestimated group
Table 3 Comparing self-perceptive weight and actual weight status of children and adolescents aged 6–17 years in China using Kappa test and Chi-square test (N = 1,369, (%))
Underweight 24 (45.28) 80 (17.13) 15 (7.18) 0.2391 134.664 Normal 28 (52.83) 364 (77.94) 128 (61.24) Overweight/Obesity 1 (1.89) 23 (4.93) 66 (31.58) Underweight 26 (43.33) 61 (14.52) 13 (8.13) 0.1447 56.761 Normal 33 (55.00) 114 (71.25) Overweight/Obesity 1 (1.67) 40 (9.52) 33 (20.63) Underweight 50 (44.25) 141 (15.90) 28 (7.59) 0.1960 178.343 Normal 61 (53.98) 683 (77.00) 242 (65.58) Overweight/Obesity 2 (1.77) 63 (7.10) 99 (26.83)
Note: The chi-square tests and the Kappa test were used to examine agreement between self-perceived weight status and actual weight status. Value is N (%). Proportions are column percentages. Bold values represent statistically significant (P < 0.05)
In the study, we documented 93 incident of dietary weight management behaviours, including 40 cases for gaining weight and 53 cases for losing weight. The difference of distribution of dietary weight management behaviours by BMI, self-perceptive weight status and BID were statistically significant (Table 4).
Table 4 Distribution of dietary weight management behaviours by BMI, Self-perceptive weight and BID among Chinese children and adolescents aged 6–17 years (N = 1,369, (%))
Variables Dietary weight management behaviours χ2 Normal 838(94.48) 24(2.71) 25(2.82) 19.4347 Underweight 106(93.81) 6(5.31) 1(0.88) Overweight/obesity 332(89.97) 10(2.71) 27(7.32) Normal 952(96.55) 16(1.62) 18(1.83) 168.2609 Underweight 206(94.06) 12(5.48) 1(0.46) Overweight/obesity 118(71.95) 12(7.32) 34(20.73) Satisfied 534(96.04) 10(1.80) 12(2.16) 65.8675 Desire to be heavier 458(96.22) 13(2.73) 5(1.05) Desire to be thinner 284(84.27) 17(5.04) 36(10.68)
Note: The chi-square tests were used to examine dietary weight management behaviours difference in terms of BMI, BID and self-perceived weight status. Value is N (%). Proportions are row percentages. Bold values represent statistically significant (P < 0.05). BMI = body mass index; BID = body image dissatisfaction
After adjusting for age (Model 1), overweight/obesity of self-perceptive weight status were significantly associated with a higher risk to take behaviours for managing their weight compared with self-perceptive weight status as normal in boys [OR (95%CI) = 7.86(3.90, 15.87)] and girls [OR (95%CI) = 13.18(6.58, 26.41)]. In boys, the associations were slightly attenuated but remained significant after further adjusting for sociodemographic characteristics including residence, grade, per capita household income, parent education level, and physical activity (Model 2) in boys [OR (95%CI) = 6.01(2.54, 14.20)]. The same was true after adjusting the BMI (Model 3) [OR (95%CI) = 5.07(1.86, 13.87)]. Meanwhile, in girls, the correlations were slightly increased after further adjusted for sociodemographic characteristics (Model 2) [OR (95%CI) = 13.93(5.86, 33.11)] and BMI (Model 3) [OR (95%CI) = 14.28(5.73, 35.56)] (Table 5).
Table 5 Association between body perception and dietary weight management behaviours in children adolescents stratified by sex in CHNS (2015)
Variables Model 1 Model 2 Model 3 OR (95% CI) OR (95% CI) OR (95% CI) Normal Ref Ref Ref Underweight 2.15(0.90, 5.12) 1.85(0.61, 5.61) 1.98(0.64, 6.12) Overweight/obesity Satisfied Ref Ref Ref Desire to be heavier 0.97(0.42, 2.21) 0.85(0.32, 2.23) 0.92(0.34, 2.47) Desire to be thinner 1.80(0.73, 4.42) 1.47(0.58, 3.72) Normal Ref Ref Ref Underweight 1.43(0.51, 3.97) 2.22(0.65, 7.61) 1.67(0.44, 6.34) Overweight/obesity Satisfied Ref Ref Ref Desire to be heavier 1.02(0.37, 2.80) 2.02(0.60, 6.76) 1.88(0.54, 6.48) Desire to be thinner
Note: Multiple logistic regression models were used in this analysis. The model 1 was adjusted for age (years). The model 2 was further adjusted for residence (urban, rural), per capita household income (lower, middle, higher), grade (elementary, junior, high), mother's education level (elementary, junior, high), father's education level (elementary, junior, high), and physical activity (no, regular). The model 3 was further adjusted for BMI (normal, underweight, overweight/ obesity). Significant between-group differences were shown in bold.
As expected, after adjusting for age, those who desire to be thinner significantly associated with a higher risk to take behaviours for managing their weight compared with those who were satisfied with their body in girls [OR (95%CI) = 6.51(3.01, 14.07)]. The change of associations between BID and dietary weight management behaviours were similar to that of self-estimated weight status after adjusting for sociodemographic characteristics [OR (95%CI) = 8.97(3.38, 23.80)] and BMI [OR (95%CI) = 9.51(3.47, 26.09)] in girls (Table 5).
This study aims to evaluate the body perception and its association with dietary weight management behaviours among Chinese children and adolescents aged 6 to 17 years. We found that the children and adolescents' body perception showed a significant association with their dietary weight management behaviours.
The finding showed that the prevalence of overweight/obesity was 26.95% and underweight was 8.26% in China (Table 2). Similarly, Zheng et al. reported the prevalence of overweight/obesity of children and adolescents was 29.8% using data from five major cities (Beijing, Shanghai, Nanjing, Xian, and Chengdu) across China [[
As another important finding from our study, there is a discrepancy in body perception (self-perceptive weight status or BID) according to sex. Boys prefer to underestimate their weight status but girls more likely to overestimate in our study. The results were consistent with the studies of Wang VH et al. [[
Back to the topic of dietary weight management behaviours, no matter boys or girls, participants whose self-perceptive weight status were overweight/obesity were most likely to have dietary weight management behaviours comparing to those whose self-perceptive weight status were normal (Table 5), which has also been confirmed in other studies [[
The dissatisfaction with one's current body image or weight fosters weight management behaviours and related cognitions in order to change one's appearance [[
This study has several limitations that need to be acknowledged. First, this study involved children and adolescents age 6 to 17 years old, but most of them are primary school students (68.81%). Hence, there were only 93 out of 1,369 study participants reported that they had weight management behaviours including gaining weight or losing weight in the past year. Therefore, the results may include a selection bias due to uneven distribution of grades, and might not represent the entire Chinese children and adolescent population. Moreover, as the data used in the current study was cross sectional, the findings were correlations, not causations, with the inability to decide the direction of the effects, thus future research should use a longitudinal design or experiments to examine how body perception interact with dietary weight management behaviours over time.
In this study, the prevalence of overweight/obesity among Chinese children and adolescents aged 6 to 17 years was 26.95%. The accuracy of weight perception and body image satisfaction is not optimistic among Chinese children and adolescents. Body perception showed a significant association with dietary weight management behaviours. It is necessary to promote healthy body image perceptions and establish self-motivation for improving basic health knowledge in school health education activities.
This research uses data from China Health and Nutrition Survey (CHNS). We are grateful to research grant funding from the National Institute for Health (NIH), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) for R01 HD30880, National Institute on Aging (NIA) for R01 AG065357, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) for R01DK104371 and R01HL108427, the NIH Fogarty grant D43 TW009077 since 1989, and the China-Japan Friendship Hospital, Ministry of Health for support for CHNS 2009, Chinese National Human Genome Center at Shanghai since 2009, and Beijing Municipal Center for Disease Prevention and Control since 2011. We thank the National Institute for Nutrition and Health, China Center for Disease Control and Prevention, Beijing Municipal Center for Disease Control and Prevention, and the Chinese National Human Genome Center at Shanghai.
L.S. and X.L. contributed to the conception and design of the study and the acquisition of data, L.S, Y.Z., T.C. and P.M. were involved in analyzing and interpreting the data. L.S. drafted the manuscript. X.L, Y.Z and T.C. were involved in critically revising the manuscript for important intellectual content. All authors read and approved the final manuscript.
The research leading to these results received funding from Chongqing medical scientific research project (Joint project of Chongqing Health Commission and Science and Technology Bureau) under Grant Agreement No. 2020FYYX013.
Data is available on request to official website of the China Health and Nutrition Survey, China. (https://
The ethics approval was obtained by the review board from the University of North Carolina at Chapel Hill, National Institute for Nutrition and Food Safety, China Center for Disease Control. All parents gave written informed consent for their children's participation in the survey, and data were anonymized for the analysis.
Not applicable
The authors declare that there are no conflicts of interest to report.
• BID
- Body image dissatisfaction
• BMI
- Body mass index
• CHNS
- China Health and Nutrition Survey
• CI
- Confidence interval
• OR
- Odds ratio
• Ref
- Reference
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