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Changes in health-related behaviors and their effect on dissatisfaction with body weight in youths

Abstracts

The aim of the present study was to establish whether changes in health-related behaviors are associated with changes in the satisfaction/dissatisfaction with body weight in youths. It was a prospective study that performed a secondary analysis of data from Project "Saúde na Boa", which included youths attending night classes in secondary public schools in Recife in the state of Pernambuco and Florianópolis in the state of Santa Catarina. Data on the youths' body type (thinness or excess weight) and degree of satisfaction/dissatisfaction with body weight and lifestyle (level of physical activity, participation in physical education classes, sedentary behavior and snacks, soda and alcohol intake) were collected at 10 schools from each town (five in the intervention group and five in the control group). The percentages of youths dissatisfied with their body weight were 50.5% and 48.6% at baseline and after intervention, respectively. The percentage of youths with body dissatisfaction due to thinness decreased (21.4% vs. 16.5%), while the percentage of youths with body dissatisfaction due to excess weight increased (29.1% vs. 32.1%). Approximately 41.2% of the youths with body dissatisfaction due to thinness and 18.3% of those dissatisfied due to excess weight became satisfied with their body weight after intervention. The intervention targeting health-related behaviors induced changes in the youths' degree of satisfaction with their body weight.

Body image; Interventional studies; Healthy behaviors; Youths


O objetivo do estudo foi identificar se as modificações nas condutas de saúde estão associadas às modificações na satisfação/insatisfação com a massa corporal em adolescentes. Estudo prospectivo, com análise secundária de dados do Projeto "Saúde na Boa", conduzido com estudantes do ensino médio matriculados em escolas públicas no período noturno de Recife/PE e Florianópolis/SC. Nas dez escolas (cinco controles e cinco intervenção) de cada cidade foram coletados dados sobre satisfação com a massa corporal e o tipo de satisfação (magreza ou excesso de peso), e informações referentes ao estilo de vida dos estudantes (atividade física, aulas de Educação Física, comportamento sedentário, consumo de salgados, refrigerantes e álcool). A prevalência de adolescentes insatisfeitos com a massa corporal na linha de base e após a intervenção foi de 50,5% e 48,6%. Verificou-se diminuição da insatisfação pela magreza (21,4% vs 16,5%) e aumento da insatisfação pelo excesso de peso (29,1% vs 32,1%). Parcela de adolescentes insatisfeitos por magreza (41,2%) e por excesso de peso (18,3%) passaram a ser satisfeitos com a massa corporal ao final da intervenção. A intervenção sobre as condutas de saúde provocou modificação na percepção de insatisfação com a massa corporal entre os adolescentes.

Adolescentes; Comportamentos saudáveis; Estudos de intervenção; Imagem corporal


INTRODUCTION

Self-perception of body weight is an important component of body image, as it is related to a person's feelings and behavior towards his or her body11. Pauline M, Selvam S, Swaminathan S, Vaz M. Body weight perception is associated with socio-economic status and current body weight in selected urban and rural South Indian school-going children. Public Health Nutr 2012;15(12):2348-56.. As a function of prevailing sociocultural influences, beauty is associated by females with a thin body, while males associate it with a large and muscular body22. Neighbors LA, Sobal J. Prevalence and magnitude of body weight and shape dissatisfaction among university students. Eat Behav. 2007; 8(4):429-39..

Excessive concern with body weight might alter the everyday behavior of adolescents, resulting in use of laxatives and other drugs without a medical prescription, excessive exercise and inappropriate diets, eventually giving rise to suicidal thoughts33. Cheung PC, Ip PL, Lam ST, Bibby H. A study on body weight perception and weight control behaviours among adolescents in Hong Kong. Hong Kong Med J 2007;13(1):16-21.

4. Fidelix YL, Silva DAS, Pelegrini A, Silva AF, Petroski EL. Body image dissatisfaction among adolescents from a small town: Association with gender, age, and area of residence. Rev Bras Cineantropom Desempenho Hum 2011;13(3):202-7.

5. Xie B, Chou CP, Spruijt-Metz D, Reynolds K, Clark F, Palmer PH, et al. Weight perception and weight-related sociocultural and behavioral factors in Chinese adolescents. Prev Med 2006;42(3):229-34.
- 66. Ursoniu S, Putnoky S, Vlaicu B. Body weight perception among high school students and its influence on weight management behaviors in normal weight students: a cross-sectional study. Wien KlinWochenschr 2011;123(11-12):327-33.. An inability to meet the culturally ideal esthetic standards might result in distortions of body image, which in turn might lead to eating disorders, failed attempts at controlling body weight and the use of anabolic steroids55. Xie B, Chou CP, Spruijt-Metz D, Reynolds K, Clark F, Palmer PH, et al. Weight perception and weight-related sociocultural and behavioral factors in Chinese adolescents. Prev Med 2006;42(3):229-34..

According to some studies, adolescents' satisfaction with their body weight varies among different cultural settings, as also do the factors associated with it11. Pauline M, Selvam S, Swaminathan S, Vaz M. Body weight perception is associated with socio-economic status and current body weight in selected urban and rural South Indian school-going children. Public Health Nutr 2012;15(12):2348-56. , 33. Cheung PC, Ip PL, Lam ST, Bibby H. A study on body weight perception and weight control behaviours among adolescents in Hong Kong. Hong Kong Med J 2007;13(1):16-21. , 66. Ursoniu S, Putnoky S, Vlaicu B. Body weight perception among high school students and its influence on weight management behaviors in normal weight students: a cross-sectional study. Wien KlinWochenschr 2011;123(11-12):327-33.. In China55. Xie B, Chou CP, Spruijt-Metz D, Reynolds K, Clark F, Palmer PH, et al. Weight perception and weight-related sociocultural and behavioral factors in Chinese adolescents. Prev Med 2006;42(3):229-34., for instance, a study found that more than 25% of the investigated adolescents described themselves as thin, and more than 30% described themselves as overweight. That study further found that factors such as the degree of exposure to mass media, attitudes towards physical appearance and the adoption of health-risk behaviors were associated with body dissatisfaction55. Xie B, Chou CP, Spruijt-Metz D, Reynolds K, Clark F, Palmer PH, et al. Weight perception and weight-related sociocultural and behavioral factors in Chinese adolescents. Prev Med 2006;42(3):229-34.. One study conducted on adolescents in Romania6 found that 22.6% of the participants with normal weight perceived themselves as overweight. In addition, the students from both genders who perceived themselves as overweight were more likely to exercise, exhibit inadequate dietary habits, take diet pills, vomit or take laxatives compared to the ones who did not perceive themselves as overweight66. Ursoniu S, Putnoky S, Vlaicu B. Body weight perception among high school students and its influence on weight management behaviors in normal weight students: a cross-sectional study. Wien KlinWochenschr 2011;123(11-12):327-33..

In addition to family, schools are also considered responsible for youth education. Particular efforts are constantly undertaken by schools to motivate youths to develop healthy habits, as these habits are likely to persist into adulthood77. Nahas MV, Barros MV, Assis MA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saúde na Boa project. J Phys Act Health 2009;6(2):153-62.. However, similarly, risk behaviors acquired by this time are also likely to persist in the future. For these reasons, schools are one of the main agencies involved in the formation of life habits and behaviors in adolescents77. Nahas MV, Barros MV, Assis MA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saúde na Boa project. J Phys Act Health 2009;6(2):153-62..

Several interventions aimed at reducing unhealthy behaviors among adolescents have been developed worldwide77. Nahas MV, Barros MV, Assis MA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saúde na Boa project. J Phys Act Health 2009;6(2):153-62.

8. Muth ND, Chatterjee A, Williams D, Cross A, Flower K. Making an IMPACT: effect of a school-based pilot intervention. N C Med J 2008;69(6):432-40.

9. Gortmaker SL, Cheung LW, Peterson KE, Chomitz G, Cradle JH, Dart H, et al. Impact of a school-based interdisciplinary intervention on diet and physical activity among urban primary school children: eat well and keep moving. Arch Pediatr Adolesc Med 1999;153(9):975-83.
- 1010. Barros MV, Nahas MV, Hallal PC, Farias Júnior JC, Florindo AA, Barros SSH. Effectiveness of a school-based intervention on physical activity for high school students in Brazil: the Saúde na Boa project. J Phys Act Health 2009;6(2):163-9., some of which exhibited satisfactory results, such as an increase in physical activity level, the development of appropriate dietary habits, smoking cessation and a reduction in stress. However, the impact of such interventions on adolescents' satisfaction/dissatisfaction with their body weight is still unknown, although this indirect effect is likely, as changes in health-related behaviors are associated with the satisfaction with body weight among adolescents. The data available in Brazil derive from cross-sectional studies that investigated the distribution of adolescents' dissatisfaction with their self-image, as well as its association with several factors1111. Glaner MF, Pelegrini A, Cordoba CL, Pozzobon ME. Associação entre insatisfação com a imagem corporal e indicadores antropométricos em adolescentes. Rev Bras Educ Fís Esporte 2013;27(1):129-36.

12. Petroski EL, Pelegrini A, Glaner MF. Motivos e prevalência de insatisfação com a imagem corporal em adolescentes. Cien Saude Colet 2011;17(4):1071-7.
- 1313. Martins CR, Pelegrini A, Matheus SC, Petroski EL. Insatisfação com a imagem corporal e sua relação com estado nutricional, adiposidade corporal e sintomas de anorexia e bulimia em adolescentes. Rev Psiquiatr Rio Gd Sul 2010;32(1):19-23..

The verification of a relationship between changes in health-related behaviors and changes in the satisfaction/dissatisfaction with body weight might result in guidelines for the incorporation of appropriate strategies to modulate those behaviors among youths into educational and health policies. If evidence shows that positive changes in health-related behaviors induce positive changes in body weight perception, then interventions targeting the youths' life habits might simultaneously stimulate the development of healthy behaviors and reflect a greater awareness of body weight perception. In addition, the existence of that relationship would allow the filling of current gaps in the understanding of the causal network that links some health-related behaviors with body weight satisfaction/dissatisfaction among youths. For those reasons, the aim of the present study was to investigate whether changes in health-related behaviors are associated with changes in the satisfaction/dissatisfaction with body weight among youths.

METHODOLOGICAL PROCEDURES

Population and sample

The present study consisted of a secondary analysis of the data collected in the randomized-controlled study "Saúde na Boa"1414. Nahas MV, Barros MV, Assis MAA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saude na Boa project. J Phys Act Health 2009;6(2):153-62.

15. Silva KS, Barros MVG, Barbosa Filho VC, Garcia LMT, Wanderley Júnior RS, Beck, CC, et al. Implementation of the "Saúde na Boa" intervention: process evaluation and characteristics of participants and dropouts. Rev Bras Cineantropom Desempenho Hum 2014; 16(Supl.1)1-12.
- 1616. Nahas MV, Barros MVG, Florindo AA, Hallal PC, Konrad L, Barros SSH, Assis MAA. Reprodutibilidade e validade do questionário saúde na boa para avaliar atividade física e hábitos alimentares em escolares do ensino médio. Rev Bras Ativ Fís Saúde 2012;12:12-20.. In that study, the aim of the intervention was to promote the development of healthy behaviors among youths attending night classes in public secondary schools at two Brazilian state capitals, Florianópolis (state of Santa Catarina - SC) and Recife (state of Pernambuco - PE) in the Southern and Northeastern regions of Brazil, respectively.

Approximately 2,000 youths aged 14 to 24 years old attending 20 randomly selected schools were assessed in March 2006 (baseline). Ten schools from each town were selected, five corresponding to the experimental group and five to the control group. The schools were matched in geographical location and size (small: up to 200 students; medium: 200 to 499 students; large: 500 or more students). A second assessment was performed nine months later (December 2006), and the response rate at follow up was 45.9% (989 participants were assessed). Detailed data related to the selected towns, target population and procedures for sample selection were described in a previous article1414. Nahas MV, Barros MV, Assis MAA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saude na Boa project. J Phys Act Health 2009;6(2):153-62.. The analysis of the participants lost to follow-up according to demographic, socioeconomic and behavioral features is provided by another article in the present supplement1515. Silva KS, Barros MVG, Barbosa Filho VC, Garcia LMT, Wanderley Júnior RS, Beck, CC, et al. Implementation of the "Saúde na Boa" intervention: process evaluation and characteristics of participants and dropouts. Rev Bras Cineantropom Desempenho Hum 2014; 16(Supl.1)1-12.. The present study included only the youths for whom valid data on body weight perception were available. Therefore, the sample of the present study comprised 771 high school students. Further detail on the sampling and study procedures are available in other published articles1414. Nahas MV, Barros MV, Assis MAA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saude na Boa project. J Phys Act Health 2009;6(2):153-62.

15. Silva KS, Barros MVG, Barbosa Filho VC, Garcia LMT, Wanderley Júnior RS, Beck, CC, et al. Implementation of the "Saúde na Boa" intervention: process evaluation and characteristics of participants and dropouts. Rev Bras Cineantropom Desempenho Hum 2014; 16(Supl.1)1-12.
- 1616. Nahas MV, Barros MVG, Florindo AA, Hallal PC, Konrad L, Barros SSH, Assis MAA. Reprodutibilidade e validade do questionário saúde na boa para avaliar atividade física e hábitos alimentares em escolares do ensino médio. Rev Bras Ativ Fís Saúde 2012;12:12-20..

Dependent variable

The dependent variable was dissatisfaction with body weight, which was created from other two variables included the data collection as follows. The participants were first asked the question "Are you satisfied with your body weight?", to which the answer options were "Yes", "No" and "I don't know". The participants who answered "Yes" were classified as satisfied with their body weight, the ones who answered "No" as dissatisfied, and the ones who answered "I don't know" were excluded from the analysis (5.5% and 3.1% of the participants at baseline and after intervention, respectively). In addition, as the literature recommends investigating whether dissatisfaction with the body weight is due to thinness or excess weight1717. Silva DA, Nahas MV, Sousa TF, Duca GF, Peres KG. Prevalence and associated factors with body image dissatisfaction among adults in southern Brazil: a population-based study. Body Image 2011;8(4):427-31., the participants were then asked the question "How do you rate your body weight?", the answer options being: "I'm too thin", "I'm somewhat thin", "My body weight is adequate (normal)", "I'm somewhat fat", and "I'm very fat". The participants who reported dissatisfaction in question 1 and rated themselves somewhat or very thin in question 2 were classified as "dissatisfied due to perceived thinness"; the ones who reported dissatisfaction in question 1 and rated themselves as somewhat or very fat in question 2 were classified as "dissatisfied due to perceived excess weight"; the ones who reported dissatisfaction in question 1 and rated themselves as having adequate weight (4.0%) in question 2 were excluded from analysis, as the answers were considered to be inconsistent.

Independent variables

The independent variables were changes in health-related behaviors. The physical activity section assessed the number of days in a typical week the participants performed physical activity for at least 60 minutes. Additionally, the performance of localized muscular strength/resistance exercises - LMR - (number of days/week) and the participation of the volunteers in physical education classes (number of days/week) were assessed. Sedentary behavior was estimated based on the time spent every day watching TV (hours/day) and at the computer or playing video games (hours/day). The dietary habits section included the frequency of snacks and soda intake (number of days/week) and the monthly alcohol consumption (number of days/month). The difference between the values at baseline and after intervention was calculated for each health-related behavior, and the results were classified as reduced, unchanged or increased. In the description of the results, the categories were ordered from the best to the worst possible scenario.

Control variables

The following demographic and socioeconomic variables were included in analysis as potential confounding factors: gender (male or female), age, skin color (black, white, brown or other), town (Florianópolis or Recife), marital status (single or other), occupation (employed, intern or not working), lives with the family (yes or no) and housing type (house, apartment or other).

Statistical analysis

Absolute and relative frequencies were used to characterize the sample at the beginning and at the end of the study. Additionally, the variation in the health-related behaviors and the degree of satisfaction/dissatisfaction with body weight were described. The chi-square test was used to investigate whether there were significant differences in the dependent and independent variables between the assessments performed at the beginning and at the end of the study. Adjusted multinomial logistic regression was used to calculate the odds ratio and 95% confidence interval corresponding to the relationship between the changes introduced in the health-related behaviors and the changes in the degree of satisfaction/dissatisfaction with body weight (the category "improved", which comprised the participants who reported dissatisfaction at baseline and satisfaction after intervention, was used as a reference). As the variable gender did not exhibit an association with the changes in the dissatisfaction with body weight and did not affect the results, the analysis was performed relative to the total sample. All the analyses were adjusted for potential confounding factors (gender, age, skin color, town, marital status, occupation, lives with the family, household type and behavior at baseline). The analysis was performed using the Stata software, v. 11 (Stata Corp., College Station, TX, USA), and the significance level was established as 5%.

Ethical issues

All the procedures performed in the present study were approved by the ethics committees of the Federal University of Santa Catarina (Universidade Federal de Santa Catarina - UFSC; 031/2005) and the Mother-Child Institute (Instituto Materno Infantil) of Pernambuco (587/2005). Passive consent forms were signed by the parents or guardians of the volunteers younger than 18 years old, as well as by students aged 18 years or older.

RESULTS

The sample comprised participants from Florianópolis, SC (52.3%) and Recife, PE (47.7%). Most of the participants were female, aged 14 to 18 years old, self-reported to be white, single, lived with their families, did not work and lived in houses (Table 1).

Table 1
Characterization of the participants at baseline with valid data for the present study (n = 771)

The prevalence of participants dissatisfied with their body weight at baseline was 50.5%, and it exhibited little variation after nine months of intervention (48.6%). Approximately 29.1% of the participants reported dissatisfaction due to excess weight at baseline, and 81.3% of them remained dissatisfied after intervention, whereas 18.3% became satisfied with their body weight (p < 0.01). Approximately 21.4% of the participants reported dissatisfaction due to thinness at baseline, and a little more than half of them remained dissatisfied after intervention, while 41.2% became satisfied with their body weight (p < 0.01). Approximately 10.2% of the participants who reported to be satisfied with their body weight at baseline (49.5%) were dissatisfied due to excess weight at the end of the study, while 14.7% reported to be dissatisfied due to thinness (Figure 1).

Figure 1
Prevalence of and changes in body weight perception at baseline and at nine-month follow up as assessed in youths attending secondary school (n = 771); * chi-square test

The results on the prevalence of the health-related behaviors at baseline and after nine months of intervention show reductions in the weekly frequency of physical activity, snacks and soda intake and monthly use of alcohol, as well as increases in the weekly frequency of LMR exercises and the time spent every day at the computer or playing video games (Table 2).

Table 2
Frequencies of health-related behaviors at baseline and after nine months of intervention (n = 771)

The analysis of the association between the changes in body weight perception and changes in health-related behaviors adjusted for potentially confounding factors (Table 3) showed that the odds ratio for maintenance of the body weight perception was higher among the participants with no changes in the weekly soda intake compared to those who reduced it. Among the participants who became dissatisfied with their body weight, maintenance of the weekly frequency of LMR exercises and of soda intake exhibited a significant association with negative changes in body weight perception. An increase in the number of hours spent each day at the computer or playing video games exhibited a significant association with a higher odds ratio for becoming dissatisfied with body weight.

Table 3
Association between body weight perception (reference category: improved perception) and health-related behaviors in youths.

DISCUSSION

The aim of the present study was to investigate whether changes in health-related behaviors are associated with changes in the satisfaction/dissatisfaction of youths with their body weight. The main finding of the present study is that changes in some health-related behaviors (not increasing the weekly frequency of LMR exercises, not reducing the weekly frequency of soda intake and increasing the amount of time spent each day at the computer or playing video games) exhibited significant associations with negative changes in the satisfaction with body weight. These results emphasize the relevance of the promotion of healthy lifestyles and show that changes in the latter might improve the satisfaction of youths with their body image.

However, the results of the present study should be interpreted cautiously as they might be distorted by possible bias because the present study consisted of a secondary analysis of data, and thus the measures of effect and associations found might result from spurious associations (black-box effect). Those limitations notwithstanding, the evidence points to a robust association between the youths' satisfaction/dissatisfaction with their body weight and their dietary habits and performance of physical activity (the main components of the intervention program)1818. Morris AM, MBBS MPH FRACP, Katzman DB, MD FRCPC. The impact of the media on eating disorders in children and adolescents . Pediatr Child Health 2003;8(5):287-9. , 1919. Bibiloni MM, Pich J, Pons A, Tur JA. Body image and eating patterns among adolescents. BMC Public Health 2013;13:1104..

The subjectivity characterizing the measures used to assess the health-related behaviors might account for the lack of an association between those variables and the participants' satisfaction/dissatisfaction with their body weight found at some moments, and consequently, this subjectivity is a limitation of the present study. One additional limitation derives from the duration of the follow-up period, nine months, which might have been too short to allow the detection of significant associations with some of the assessed variables. Finally, the loss of more than 50% of the sample is another limitation.

The prevalence rates of youths dissatisfied with their body weight were 50.5% and 48.6% at baseline and after intervention, respectively. Approximately 29.1% of the sample reported dissatisfaction due to excess weight at baseline, and almost one fifth of the participants became satisfied with their body weight after intervention. Approximately 21.4% of the sample reported dissatisfaction due to thinness, and 41.2% of these participants became satisfied with their body weight after intervention. These findings show that the investigated intervention changed the perception and satisfaction/dissatisfaction of the youths with their body weight, and thus, they disagree with the results of studies that did not find positive changes in the degree of satisfaction of youths with their body weight2020. Stice E, Whitenton K. Risk factors for body dissatisfaction in adolescent girls: a longitudinal investigation. Dev Psychol 2002;38(5):669-78.. One longitudinal study that followed youths from Minnesota, USA over 10 years found that the female and male participants' body dissatisfaction increased between middle and high school, that the body dissatisfaction increased further during the transition to young adulthood and that this increase was associated with an increase in the body mass index (BMI) over time2121. Bucchianeri MM, Arikian AJ, Hannan PJ, Eisenberg ME, Neumark-Sztainer D. Body dissatisfaction from adolescence to young adulthood: findings from a 10-year longitudinal study. Body Image 2013;10(1):1-7.. One study that investigated the relationships between longitudinal weight status, body dissatisfaction and the attitude toward weight loss among South Korean children from the ages of 7-8 to 13-14 years old found that the girls favored thinner shapes than the boys did, regardless of weight status or changes in BMI. In contrast, in the boys, the desire to lose weight was related only to weight loss attempts and was independent of the weight status, BMI changes and level of body dissatisfaction2222. Lee K, Sohn H, Lee S, Lee J. Weight and BMI over 6 years in Korean children: relationships to body image and weight loss efforts. Obes Res 2004;12(12):1959-1966..

The studies conducted in Brazil with a cross-sectional design show that youths exhibit high levels of body dissatisfaction1111. Glaner MF, Pelegrini A, Cordoba CL, Pozzobon ME. Associação entre insatisfação com a imagem corporal e indicadores antropométricos em adolescentes. Rev Bras Educ Fís Esporte 2013;27(1):129-36. , 1212. Petroski EL, Pelegrini A, Glaner MF. Motivos e prevalência de insatisfação com a imagem corporal em adolescentes. Cien Saude Colet 2011;17(4):1071-7.. Those findings are a source of concern, as dissatisfaction with body image is associated with eating disorders1313. Martins CR, Pelegrini A, Matheus SC, Petroski EL. Insatisfação com a imagem corporal e sua relação com estado nutricional, adiposidade corporal e sintomas de anorexia e bulimia em adolescentes. Rev Psiquiatr Rio Gd Sul 2010;32(1):19-23..

In the present study, the participants who did not change their frequency of soda intake exhibited a higher likelihood of maintaining a negative perception of their body weight compared to those who reduced it. These findings agree with the results of a study conducted on Spanish teenagers (12 to 17 years old), which found greater soda intake among overweight participants dissatisfied with their body image compared to the overweight participants satisfied with their body image1919. Bibiloni MM, Pich J, Pons A, Tur JA. Body image and eating patterns among adolescents. BMC Public Health 2013;13:1104.. In the present study, unchanged frequencies of LMR exercises and soda intake exhibited a significant association with negative changes in body weight perception. One study conducted on college students found that body image was a significant factor in determining the amount of exercise for a majority of the participants (58.3%)2323. Brudzynski L, Ebben WP. Body image as a motivator and barrier to exercise participation. Int J Exerc Sci 2010;3(1):14-24.. According to the literature, adolescents who perceive themselves as overweight are more likely to exercise to lose weight compared to those who do not perceive themselves as overweight2424. Ingledew DK, Sullivan G. Effects of body mass and body image on exercise motives in adolescence. Psychol Sport Exerc 2002;3(1):323-38.. Dissatisfaction with body image might both motivate the participants to exercise2424. Ingledew DK, Sullivan G. Effects of body mass and body image on exercise motives in adolescence. Psychol Sport Exerc 2002;3(1):323-38. and facilitate exercise2525. Focht BC, Hausenblas HA. Perceived evaluative threat and state anxiety during exercise in women with social physique anxiety. J Appl Sport Psychol 2004;16(4):361-8..

Increases in the time spent at the computer or playing video games exhibited a significant association with individuals becoming dissatisfied with their body weight. According to the literature, in addition to the BMI, the social pressure to be thin and the internalization of the ideal body image prescribed by the mass media and society at large are strong predictors of body dissatisfaction2020. Stice E, Whitenton K. Risk factors for body dissatisfaction in adolescent girls: a longitudinal investigation. Dev Psychol 2002;38(5):669-78.. Adolescents are vulnerable to the messages and images conveyed by the mass media, and some of them are unable to discriminate these images from reality; they are often unaware of the manipulation of images by digital technologies that often results in unrealistic body ideals, which are impossible to attain1818. Morris AM, MBBS MPH FRACP, Katzman DB, MD FRCPC. The impact of the media on eating disorders in children and adolescents . Pediatr Child Health 2003;8(5):287-9..

The following strong points of the present study stand out. First, its prospective design allowed the analysis of changes in the participants' health-related behaviors and their association with changes in the satisfaction/dissatisfaction with body weight. Second, the inclusion of various types of health-related behaviors allowed for the analysis of several factors potentially associated with body dissatisfaction, thus denoting that the scope of this subject should be more comprehensive when it relates to youths. Finally, the sample comprised participants from two towns located in Brazilian areas exhibiting different sociocultural profiles, which allows for a broader extrapolation of the results.

CONCLUSIONS

The intervention investigated in the present study changed the degree of dissatisfaction of the assessed youths with their body weight. A fraction of the participants who reported dissatisfaction due to thinness (41.2%) or excess weight (18.3%) became satisfied with their body weight after intervention. The factors that exhibited significant associations with the shift from initial satisfaction to dissatisfaction with body weight at the end of the study were a lack of an increase in the frequency of LMR exercises, a lack of a reduction in the frequency of soda intake and an increase in the time spent every day at the computer or playing video games. Future interventional studies, including those on strategies designed to induce changes in body weight perception, might improve the degree of satisfaction of youths with their body image and consequently promote changes in a series of health-related behaviors.

Acknowledgments

The present study was supported by a Healthy Lifestyles, Healthy People Project scholarship endowed by the International Life Sciences Institute Research Foundation (ILSI RF), Pan American Health Organization (PAHO) and the US Centers for Disease Control and Prevention (CDC). The study was also supported by the National Council of Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq, Ministry of Science and Technology, Brazil), the Federal University of Santa Catarina (Universidade Federal de Santa Catarina - UFSC) and Pernambuco State University (Universidade Estadual de Pernambuco - UPE). The authors thank the students and teachers from the 20 schools that participated in the project, as well as the State Education Secretaries of Santa Catarina and Pernambuco.

REFERENCES

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  • 2
    Neighbors LA, Sobal J. Prevalence and magnitude of body weight and shape dissatisfaction among university students. Eat Behav. 2007; 8(4):429-39.
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    Cheung PC, Ip PL, Lam ST, Bibby H. A study on body weight perception and weight control behaviours among adolescents in Hong Kong. Hong Kong Med J 2007;13(1):16-21.
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    Fidelix YL, Silva DAS, Pelegrini A, Silva AF, Petroski EL. Body image dissatisfaction among adolescents from a small town: Association with gender, age, and area of residence. Rev Bras Cineantropom Desempenho Hum 2011;13(3):202-7.
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    Xie B, Chou CP, Spruijt-Metz D, Reynolds K, Clark F, Palmer PH, et al. Weight perception and weight-related sociocultural and behavioral factors in Chinese adolescents. Prev Med 2006;42(3):229-34.
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    Ursoniu S, Putnoky S, Vlaicu B. Body weight perception among high school students and its influence on weight management behaviors in normal weight students: a cross-sectional study. Wien KlinWochenschr 2011;123(11-12):327-33.
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    Nahas MV, Barros MV, Assis MA, Hallal PC, Florindo AA, Konrad L. Methods and participant characteristics of a randomized intervention to promote physical activity and healthy eating among brazilian high school students: the Saúde na Boa project. J Phys Act Health 2009;6(2):153-62.
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Publication Dates

  • Publication in this collection
    July 2014

History

  • Received
    25 Feb 2014
  • Accepted
    02 Apr 2014
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