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Longitudinal and Secular Trends in Parental Encouragement for Healthy Eating, Physical Activity, and Dieting Throughout the Adolescent Years

      Abstract

      Purpose

      Parental encouragement for healthy eating and physical activity has been found to be associated with the long-term healthy habits of adolescents, whereas parental encouragement to diet has been associated with disordered eating behaviors among adolescents. However, little is known about how parental encouragement changes as adolescents grow older (longitudinal trends), or how parental encouragement has changed over time (secular trends). This study examined 5-year longitudinal and secular trends in adolescents' report of their parents' encouragement to eat healthily, be physically active, and diet.

      Methods

      Project Eating Among Teens surveyed a cohort of Minnesota adolescents (n = 2,516) in the years 1999 and 2004. Mixed-model regressions were used to assess changes in adolescents' reports of parental encouragement from early to middle adolescence (middle school to high school) and from middle to late adolescence (high school to post-high school), and secular changes in parental encouragement among middle adolescents between the years 1999 and 2004.

      Results

      Longitudinally, there were significant decreases in parental encouragement to eat healthy food, be active, and diet between early and middle adolescence. Between middle and late adolescence, among males parental encouragement for all behaviors decreased, whereas among females parental encouragement to diet increased. Few secular changes in parental encouragement were observed between 1999 and 2004.

      Conclusion

      Given the importance of parental support for healthy eating and physical activity, efforts should be made to help parents maintain a high level of encouragement for their children's healthy behavior throughout adolescence. Parents of late adolescent females should aim to decrease the pressure on their daughters to diet during these critical developmental years.

      Keywords

      Developing and maintaining regular physical activity and healthy dietary intake habits during adolescence contributes to several positive health outcomes, including healthy weight maintenance, into the adult years [
      • Menschik D.
      • Ahmed S.
      • Alexander M.H.
      • Blum R.W.
      Adolescent physical activities as predictors of young adult weight.
      ,
      • Ritchie L.D.
      • Spector P.
      • Stevens M.J.
      • et al.
      Dietary patterns in adolescence are related to adiposity in young adulthood in black and white females.
      ,
      • Albertson A.M.
      • Franko D.L.
      • Thompson D.
      • et al.
      Longitudinal patterns of breakfast eating in black and white adolescent girls.
      ]. Conversely, adolescents' use of dieting and unhealthy weight control behaviors, including skipping meals and using diet pills and laxatives, may be ineffective in achieving weight loss and may even contribute to excessive weight gain and other negative health outcomes [
      • Savage J.S.
      • Birch L.L.
      Patterns of weight control strategies predict differences in women's 4-year weight gain.
      ,
      • Neumark-Sztainer D.
      • Wall M.
      • Guo J.
      • et al.
      Obesity, disordered eating, and eating disorders in a longitudinal study of adolescents: How do dieters fare five years later?.
      ].
      In general, studies suggest that parental encouragement and support play a critical role in adolescents' development of physical activity, dietary intake, and weight control habits. Parental encouragement to make healthy food choices has been associated with several positive dietary habits among adolescents including higher intake of fruit and vegetables [
      • Pearson N.
      • Biddle S.J.
      • Gorely T.
      Family correlates of fruit and vegetable consumption in children and adolescents: A systematic review.
      ,
      • Granner M.L.
      • Sargent R.G.
      • Calderon K.S.
      • et al.
      Factors of fruit and vegetable intake by race, gender, and age among young adolescents.
      ] and intake of calcium-rich foods [
      • Edlefsen M.
      • Reicks M.
      • Goldberg D.
      • et al.
      Strategies of Asian, Hispanic, and non-Hispanic white parents to influence young adolescents' intake of calcium-rich foods, 2004 and 2005.
      ]; parental encouragement and support for physical activity has been associated with healthy physical activity habits among adolescents, as has been reported in several cross-sectional and longitudinal studies [
      • Heitzler C.D.
      • Martin S.L.
      • Duke J.
      • Huhman M.
      Correlates of physical activity in a national sample of children aged 9–13 years.
      ,
      • Kuo J.
      • Voorhees C.C.
      • Haythornthwaite J.A.
      • Young D.R.
      Associations between family support, family intimacy, and neighborhood violence and physical activity in urban adolescent girls.
      ,
      • Trost S.G.
      • Sallis J.F.
      • Pate R.R.
      • et al.
      Evaluating a model of parental influence on youth physical activity.
      ,
      • Springer A.E.
      • Kelder S.H.
      • Hoelscher D.M.
      Social support, physical activity and sedentary behavior among 6th-grade girls: A cross-sectional study.
      ,
      • Dowda M.
      • Dishman R.K.
      • Pfeiffer K.A.
      • Pate R.R.
      Family support for physical activity in girls from 8th to 12th grade in South Carolina.
      ]. Among the sociodemographically diverse population of adolescents who participated in Project Eating Among Teens (EAT), parental encouragement to eat healthy food was associated with increased intake of fruit and vegetables and was shown to protect against increased intake of fast food over a 5-year period [
      • Neumark-Sztainer D.
      • Wall M.
      • Perry C.
      • Story M.
      Correlates of fruit and vegetable intake among adolescents Findings from Project EAT.
      ,
      • Larson N.I.
      • Neumark-Sztainer D.R.
      • Harnack L.J.
      • et al.
      Fruit and vegetable intake correlates during the transition to young adulthood.
      ,
      • Bauer K.W.
      • Larson N.I.
      • Nelson M.C.
      • et al.
      Socio-environmental, personal and behavioural predictors of fast-food intake among adolescents.
      ]; parental encouragement for physical activity was associated with higher physical activity through adolescence [
      • Bauer K.W.
      • Nelson M.C.
      • Boutelle K.N.
      • Neumark-Sztainer D.
      Parental influences on adolescents' physical activity and sedentary behavior: Longitudinal findings from Project EAT-II.
      ].
      In contrast, parental encouragement of their adolescents to diet to control weight has been associated with several negative outcomes including excessive worry about weight, binge eating, and use of unhealthy weight control behaviors [
      • Meesters C.
      • Muris P.
      • Hoefnagels C.
      • van Gemert M.
      Social and family correlates of eating problems and muscle preoccupation in young adolescents.
      ,
      • Dixon R.
      • Adair V.
      • O'Connor S.
      Parental influences on the dieting beliefs and behaviors of adolescent females in New Zealand.
      ,
      • Kluck A.S.
      Family influence on disordered eating: The role of body image dissatisfaction.
      ,
      • Neumark-Sztainer D.
      • Bauer K.W.
      • Friend S.
      • et al.
      Family weight talk and dieting: How much do they matter for body dissatisfaction and disordered eating behaviors in adolescent girls?.
      ]. Among adolescents in Project EAT, maternal encouragement of their sons to diet was associated with sons' increased risk of binge eating, dieting, and using unhealthy weight control behaviors [
      • Fulkerson J.A.
      • McGuire M.T.
      • Neumark-Sztainer D.
      • et al.
      Weight-related attitudes and behaviors of adolescent boys and girls who are encouraged to diet by their mothers.
      ]; parental encouragement of their overweight child to diet was associated with higher risks of depression, lower self-esteem [
      • Fulkerson J.A.
      • Strauss J.
      • Neumark-Sztainer D.
      • et al.
      Correlates of psychosocial well-being among overweight adolescents: The role of the family.
      ], and being overweight after 5 years [
      • Neumark-Sztainer D.
      • Wall M.
      • Story M.
      • van den Berg P.
      Accurate parental classification of overweight adolescents' weight status: Does it matter?.
      ].
      Despite the importance of parental encouragement of adolescents' behaviors, apart from intervention studies [
      • Deforche B.
      • De Bourdeaudhuij I.
      • Tanghe A.
      • et al.
      Changes in physical activity and psychosocial determinants of physical activity in children and adolescents treated for obesity.
      ], to our knowledge only one study has examined how weight-related parenting practices change as adolescents mature through adolescence. Among a sample of girls, Davison and Jago [
      • Davison K.K.
      • Jago R.
      • et al.
      Change in parent and peer support across ages 9 to 15 yr and adolescent girls' physical activity.
      ] observed that parental provision of logistical support for their daughters' physical activity declined during early adolescence. As adolescents become older and show more independence, parents may spend less time with their children. Because of this, parents may have fewer opportunities to provide encouragement and/or adolescents may not feel as supported by their parents as they used to. Despite the increasing autonomy of adolescents, research suggests that family relationships and the role of parents often evolve and may grow stronger as adolescents transition into young adulthood [
      • Nelson M.C.
      • Story M.
      • Larson N.I.
      • et al.
      Emerging adulthood and college-aged youth: An overlooked age for weight-related behavior change.
      ,
      • Lau R.R.
      • Quadrel M.J.
      • Hartman K.A.
      Development and change of young adults' preventive health beliefs and behavior: Influence from parents and peers.
      ], providing an important opportunity for parents to have a long-term impact on their children's behavior. Understanding how parental encouragement for healthy eating, physical activity, and dieting change during the adolescent years can inform public health and clinical efforts by identifying key developmental points at which parents may need additional guidance on how best to support their children.
      Additionally, to our knowledge, no study has examined secular trends in parental encouragement for healthy eating, physical activity, and dieting. Secular trends identify how parenting practices have changed over time and may reflect changes in the social environment. For example, parental encouragement for weight-related behaviors may be affected by increased media attention to childhood obesity [
      • Lawrence R.G.
      Framing obesity: The evolution of news discourse on a public health issue.
      ], the proliferation of unhealthy food options in communities [
      • Powell L.M.
      • Chaloupka F.J.
      • Bao Y.
      The availability of fast-food and full-service restaurants in the United States: Associations with neighborhood characteristics.
      ], or increased opportunities for adolescents to engage in sedentary behavior [
      • Anderson P.M.
      • Butcher K.E.
      Childhood obesity: Trends and potential causes.
      ]. By examining secular trends obtained by comparing adolescents of the same age at two different periods, changes in parenting practices that may be a reaction to societal shifts such as these can be better understood.
      The current study used data from Project EAT, a 5-year longitudinal study of adolescents, to examine simultaneously (1) longitudinal changes in adolescents' perception of their parents' encouragement to eat healthy food, be physically active, and to diet to control their weight, as they age from early to middle adolescence, and middle adolescence to late adolescence, and (2) secular changes in adolescents' perception of their parents' encouragement to eat healthy food, be physically active, and to diet to control their weight among middle adolescents (high school-aged) between the years 1999 and 2004.

      Methods

      Overview

      During the academic year 1998–1999, Project EAT enrolled 4,746 participants including a younger cohort of middle-school students and an older cohort of high school students. Project EAT aimed to resurvey by mail the original participants 5 years later (2003–2004) to assess changes in their eating and physical activity patterns and weight status. Of the original study population, 22.5% (1,074) were lost to follow-up, whereas 2,516 of the remaining 3,672 participants who were contacted by mail completed the surveys. These 2,516 participants represent 53% of the original study sample and 68.4% of participants who could be contacted. One-third of the participants (32.0%) were in the younger cohort; at time 1 their mean age was 12.8 years (standard deviation [SD] = .8) and at time 2 their mean age was 17.2 years (SD = .6). Two-thirds of the participants (68.0%) were in the older cohort; at time 1, their mean age was 15.8 years (SD = .8) and at time 2 their mean age was 20.4 years (SD = .8). The University of Minnesota's Institutional Review Board Human Subjects Committee approved all study protocols.

      Measures

      Parental encouragement

      The Project EAT surveys included six items assessing the extent to which the adolescents' parents encouraged them to eat healthy food, be physically active, and to diet to control their weight (two items per topic for both mother and father). Response options to these questions were: “not at all,” “a little bit,” “somewhat,” and “very much.” Scoring of these items thus ranged from 1 to 4. The 2-week test–retest correlation among 161 adolescents was .70 for the items associated with parental encouragement to eat healthy food, .66 and .69 for the items associated with encouragement to be physically active, and .58 and .64 for the items associated with encouragement to diet. Adolescents' responses to the mother and father items were averaged to produce a mean value for each type of encouragement. If an adolescent was missing a response for either one of their parents, the response for the remaining parent was used.

      Covariates

      Gender, race/ethnicity, and socioeconomic status (SES) were based on adolescents' self-report in 1999. Race/ethnicity was assessed with the question: “Do you think of yourself as … White, Black or African American, Hispanic or Latino, Asian American, Hawaiian or Pacific Islander, or American Indian or Native American.” Subjects could choose more than one category. Because of the small number of respondents in some of the racial/ethnic categories, Hawaiian or Pacific Islander, American Indian or Native American, and mixed heritage were combined to form a “mixed/other” category for this analysis. SES was primarily determined by adolescents' parental educational level, defined by the highest level of educational attainment of either parent [
      • Neumark-Sztainer D.
      • Story M.
      • Hannan P.J.
      • Croll J.
      Overweight status and eating patterns among adolescents: Where do youths stand in comparison with the Healthy People 2010 objectives?.
      ].
      Adolescents' body mass index (BMI) was derived from the formula: weight in kilograms divided by the square of height in meters. At time 1, surveys were completed within school classes and participants both self-reported their height and weight and had their height and weight measured by trained study staff. At time 2, surveys were mailed to study participants and only self-reported heights and weights were collected. In examining trends, self-reported data at both time points were used. In cases in which self-reported BMI data at time 1 were not available, but measured BMI data were available (n = 116), item imputation was carried out on the basis of measured BMI, age, race, and SES, within gender. At time 1, BMI values based on measured and self-reported heights and weight were found to be highly correlated (r = .85 for females and .89 for males) [
      • Himes J.H.
      • Hannan P.
      • Wall M.
      • Neumark-Sztainer D.
      Factors associated with errors in self-reports of stature, weight, and body mass index in Minnesota adolescents.
      ]. Thus, BMI based on reported height and weight has much surrogate information for estimation of expected self-reported BMI.

      Statistical analyses

      Longitudinal and secular trends were estimated with individuals who had no missing data at both time points using mixed-model regression [
      • Diggle P.J.
      • Heagerty P.
      • Liang K.Y.
      • Zeger S.L.
      Analysis of longitudinal data.
      ]. Mixed-model regressions included a main effect for year of survey, for being in the younger or middle adolescent cohort at time 1, and for the interaction of these two factors to assess differences in perceived parental encouragement across time, both within and between stages of adolescence. A random effect for individuals was used to account for longitudinal correlation. All mixed-model regressions were adjusted for baseline race/ethnicity, SES, and BMI at time 1, and analyses were stratified by gender because gender differences were expected. Adjustment for age (in years) was made in the mixed-model regression so that estimates and tests for secular changes among middle adolescents could compare participants in the older cohort in 1999 and participants in the younger cohort in 2004. Weight status-specific analyses compared adolescents who remained normal weight between time 1 and 2 versus those who remained overweight/obese between time 1 and 2, and race/ethnicity-specific analyses compared white versus non-white participants and white versus black/African American participants. To provide a standardized estimate of the difference in parental encouragement between periods, effect sizes were calculated for those estimates that were statistically significant at p < .05 by dividing the difference in the two time points by the gender-specific common standard deviation. A rule of thumb for assessing the magnitude of an effect size is that an effect size <.2 is considered to be a small change, .2–.5 a moderate change, and >.8 a large change [
      • Cohen J.
      Statistical power analysis for the behavioral sciences.
      ].
      Attrition in the study population between time 1 and 2 did not occur at random; however, no significant differences were observed in the mean levels of parental encouragement at time 1 after adjustment for age, race/ethnicity, and stratified by gender for those who participated in Project EAT at time 1 compared with those who did not. To create estimates that were representative of the original sample, and therefore improve the generalizability of study findings to the original population of Project EAT, data were weighted to adjust for differential response rates at the second survey period using a response propensity method [
      • Little R.
      Survey nonresponse adjustments for estimates of means.
      ]. The weighted racial/ethnic and SES proportions were: 52% white, 16% black/African American, 5% Hispanic, 19% Asian, and 8% mixed/other race. SES proportions were: low (16%), middle-low (19%), middle (27%), middle-high (24%), and high (14%). SAS software (v9.2, SAS Institute, Inc, Cary, NC, 2008) was used for analyses.

      Results

      Longitudinal trends in parental encouragement: early to middle adolescence

      During the transition from early to middle adolescence, significant decreases were observed in both males' and females' reports of all three types of parental encouragement––perceived encouragement by parents to eat healthy food (p < .001 for males and females), encouragement to be physically active (p < .001 for males and females), and encouragement to diet (p < .001 for males, p = .02 for females) (Table 1). The decrease in perceived encouragement to eat healthy food between early and middle adolescence was moderate, with effect sizes of .32 and .39 for males and females, respectively. Similarly, the decreases in perceived encouragement to be physically active for male and female adolescents in the younger cohort were moderate, with effect sizes of .31 and .41, respectively. Although the decrease in encouragement to diet was significant among both the younger male and female adolescents, the decrease was smaller among females with an effect size of .14 for females compared with an effect size of .36 for males.
      Table 1Longitudinal and secular (1999–2004) changes in parental encouragement for healthy eating, physical activity, and dieting to control weight
      Models adjusted for race/ethnicity, SES, age, and BMI.
      Type of encouragementLongitudinal trend: younger adolescentsLongitudinal trend: older adolescentsSecular trend
      Early adolescence, 1999Middle adolescence, 2004p for longitudinal trendMiddle adolescence, 1999Late adolescence, 2004p for longitudinal trendMiddle adolescence change, 2004–1999p for secular trend
      Mean (SE)Mean (SE)Mean (SE)Mean (SE)Mean change (SE)
      Parental encouragement to eat healthy foods (range: 1–4)
      Males3.0 (.05)2.7 (.05)<.0012.8 (.04)2.7 (.04).03−.06 (.07)
      Explanation of secular trend value: For example, in 2004 middle-adolescent males reported lower (−.06 units) parental encouragement to eat healthy food compared with middle-adolescent males in 1999. This decrease was not statistically significant.
      .41
      Females3.1 (.05)2.7 (.05)<.0012.8 (.03)2.8 (.03).26−.10 (.06).12
      Parental encouragement to be physically active (range: 1–4)
      Males3.2 (.05)2.9 (.06)<.0013.0 (.04)2.8 (.04)<.001−.10 (.07).15
      Females3.1 (.05)2.7 (.05)<.0012.8 (.04)2.7 (.03).11−.07 (.07).26
      Parental encouragement to diet to control weight (range: 1–4)
      Males1.7 (.05)1.4 (.05)<.0011.6 (.03)1.5 (.03).02−.14 (.06).03
      Females1.6 (.04)1.5 (.04).021.5 (.03)1.6 (.03).003.01 (.06).80
      a Models adjusted for race/ethnicity, SES, age, and BMI.
      b Explanation of secular trend value: For example, in 2004 middle-adolescent males reported lower (−.06 units) parental encouragement to eat healthy food compared with middle-adolescent males in 1999. This decrease was not statistically significant.

      Longitudinal trends in parental encouragement: middle to late adolescence

      Among males in the older cohort, longitudinal decreases were seen for perceived parental encouragement to eat healthy food (p = .03), be physically active (p < .001), and to diet to control weight (p = .02). As compared with findings from the younger adolescents, the effect sizes for these decreases among the older adolescents were smaller, ranging from .12 for both encouragement to eat healthy food and diet, to .23 for encouragement to be physically active. No significant longitudinal changes were seen in perceived parental encouragement to eat healthy food and be physically active among female adolescents in the older cohort. However, an increase in parental encouragement to diet was observed among older females as they transitioned from middle to late adolescence (p = .003); the effect size for this increase was relatively small (.14).

      Secular changes in parental encouragement (1999–2004)

      Secular changes in parental encouragement were also examined among middle adolescents in 2004 as compared with those in 1999. The only statistically significant change was a decrease in males' report of parental encouragement to diet (p = .03). This change represents a small effect size of .13.

      Weight status and race/ethnicity-specific findings

      To determine whether the trends in adolescents' perception of their parents' encouragement varied by adolescents' weight status, longitudinal and secular trends for each type of encouragement were estimated separately for adolescents who were normal weight (BMI percentile, <85th) versus overweight/obese (BMI percentile, ≥85th) at both time 1 and 2. No differences in the trends were observed between these groups.
      Longitudinal and secular trends were also examined by adolescents' race/ethnicity, comparing white and non-white adolescents, and white and black/African American adolescents. For females, no significant differences were observed by race/ethnicity. Among males, black/African American male adolescents reported significantly larger decreases in parental encouragement to eat healthy food between early and middle adolescence (2.9–2.0, p < .001) and in encouragement to be physically active between early and middle adolescence (3.2–2.2, p < .001), as compared with white male adolescents (healthy food: 3.0–2.9, p = .09; physical activity: 3.2–3.1, p = .05). Largely driven by the relatively low report of parental encouragement by middle adolescent black/African American males in 2004, significant secular decreases in parental encouragement to eat healthy (1999: 2.9–2004: 2.1, p < .001) and be physically active (1999: 3.1–2004: 2.2, p = .001) were observed among black/African American male adolescents. Additionally, a large secular decrease in parental encouragement to diet was observed among black/African American males (1999: 1.9 2004: 1.4, p = .009). No secular changes were observed among white males.

      Discussion

      This study examined longitudinal and secular changes in parental encouragement of adolescents to eat healthy food, be physically active, and to diet to control their weight. Both male and female adolescents reported that parental encouragement for all of these behaviors decreased between early and middle adolescence, when the adolescents were transitioning between middle and high school. Males in the older cohort, transitioning from middle to late adolescence, also reported decreases in all three types of parental encouragement. No changes in parental encouragement to eat healthy food and be physically active were observed among older females; however, females moving from middle to late adolescence reported an increase in parental encouragement to diet. Race/ethnicity-specific analyses revealed that, compared with white males, black/African American males reported larger decreases in parental encouragement to eat healthy food and be active between early and middle adolescence, and larger secular decreases in all types of encouragement between the years 1999 and 2004.
      The decreases in adolescents' perception of parental encouragement observed between early and middle adolescence, and among males between middle and late adolescence, may be attributed to adolescents' increasing independence and autonomy in making health behavior decisions [
      • Story M.
      • Neumark-Sztainer D.
      • French S.
      Individual and environmental influences on adolescent eating behaviors.
      ] or increasing conflict around parents' attempts to intervene on their child's activity and dietary intake [
      • Hattersley L.A.
      • Shrewsbury V.A.
      • King L.A.
      • et al.
      Adolescent-parent interactions and attitudes around screen time and sugary drink consumption: A qualitative study.
      ]. Parents may decrease their encouragement for their children's health behaviors, either purposely or unintentionally, as they feel that their children are making more decisions on their own and are less receptive to their parents' opinions. Additionally, as adolescents self-reported parental encouragement, study results may reflect changes in adolescents' perception rather than changes in parental behavior. As adolescents become older they may be spending less time with their family, or they may be more focused on school or other interests than before, and may perceive less parental encouragement than at previous points in their life regardless of actual changes in parental behavior. Particularly concerning are the large decreases in perceived parental encouragement for healthy behavior among black/African American males between early and middle adolescence. Further research is needed to understand changes in the parent–child relationship during adolescence among this population, and identify specific ways that black/African American families can ensure that their sons feel encouraged to eat healthy food and to be active.
      On the basis of previous findings from Project EAT [
      • Larson N.I.
      • Neumark-Sztainer D.R.
      • Harnack L.J.
      • et al.
      Fruit and vegetable intake correlates during the transition to young adulthood.
      ,
      • Bauer K.W.
      • Larson N.I.
      • Nelson M.C.
      • et al.
      Socio-environmental, personal and behavioural predictors of fast-food intake among adolescents.
      ,
      • Bauer K.W.
      • Nelson M.C.
      • Boutelle K.N.
      • Neumark-Sztainer D.
      Parental influences on adolescents' physical activity and sedentary behavior: Longitudinal findings from Project EAT-II.
      ,
      • Larson N.I.
      • Story M.
      • Wall M.
      • Neumark-Sztainer D.
      Calcium and dairy intakes of adolescents are associated with their home environment, taste preferences, personal health beliefs, and meal patterns.
      ] and other studies of adolescents [
      • Pearson N.
      • Biddle S.J.
      • Gorely T.
      Family correlates of fruit and vegetable consumption in children and adolescents: A systematic review.
      ,
      • Dowda M.
      • Dishman R.K.
      • Pfeiffer K.A.
      • Pate R.R.
      Family support for physical activity in girls from 8th to 12th grade in South Carolina.
      ,
      • Larson N.I.
      • Neumark-Sztainer D.R.
      • Harnack L.J.
      • et al.
      Fruit and vegetable intake correlates during the transition to young adulthood.
      ] showing that parental encouragement for healthy eating and physical activity has the potential to help adolescents' improve or maintain healthy behaviors into middle and late adolescence, efforts should be made to clarify why adolescents' perception of parental encouragement for healthy behaviors declines during this period. If parents have decreased the amount of encouragement they provide their children, parents may need guidance from healthcare providers and public health interventions on novel and creative ways to communicate with their adolescents, who may be spending increasing time out of the home. Specifically, adolescents may benefit from their parents identifying alternative and more subtle methods to support their adolescents' healthy behavior, including making healthy food accessible in the home or providing transportation or financial resources so that adolescents can participate in various types of physical activity.
      The increase in perceived parental encouragement to diet among girls maturing from middle to late adolescence is of concern considering the negative physical and emotional outcomes associated with parental encouragement to diet, including excessive weight concerns and disordered eating behaviors [
      • Meesters C.
      • Muris P.
      • Hoefnagels C.
      • van Gemert M.
      Social and family correlates of eating problems and muscle preoccupation in young adolescents.
      ,
      • Dixon R.
      • Adair V.
      • O'Connor S.
      Parental influences on the dieting beliefs and behaviors of adolescent females in New Zealand.
      ,
      • Kluck A.S.
      Family influence on disordered eating: The role of body image dissatisfaction.
      ]. Although by late adolescence young women may have moved out of the home, research suggests that parents' attitudes about weight and dieting and encouragement of their daughters to diet can still negatively affect young women's body satisfaction and risk for disordered eating [
      • Kluck A.S.
      Family influence on disordered eating: The role of body image dissatisfaction.
      ]. The increase in females' perception of parental encouragement to diet observed in the current study may be driven by parental concern about potential weight gain as their daughters begin post–high school pursuits. Although parents may be attempting to discuss weight and dieting to promote a healthy lifestyle among their children, this perceived encouragement to engage in dieting behavior may have unintentional negative consequences for adolescents. Additionally, girls may report greater encouragement to diet from their parents as they move into late adolescence because of experiencing increased societal pressure to be thin, and attribute some of that pressure to their parents. Regardless of whether the increase in girls' perceived encouragement to diet is a result of changes in parental behavior or adolescents' perception of their parents' behavior, greater understanding of how parents and adolescents talk about weight, weight gain, pressure to be thin, and dieting is needed.
      The secular declines in parental encouragement for healthy behaviors among black/African American boys and lack of secular change observed among other racial/ethnic and gender groups is surprising considering the dramatic increase in societal attention to childhood obesity during the study period. For example, between 1999 and 2003 news coverage in the United States of obesity nearly tripled [
      • Lawrence R.G.
      Framing obesity: The evolution of news discourse on a public health issue.
      ]. These counterintuitive findings may be because in response to increased awareness of obesity parents changed their weight-related parenting practices in ways not assessed in the current study, such as increasing their modeling of healthy behavior or modifying the types of food available in their home. It may also be that 5 years is too short a time for significant changes in parenting practices to occur.
      Strengths of this study include its longitudinal design and inclusion of both middle and high school-aged adolescents at baseline, which allowed for simultaneous examination of longitudinal and secular trends. Additionally, the use of a racially, ethnically, and socioeconomically diverse study sample allows for generalization of these findings to other populations of adolescents in the United States. A limitation of the current study is the small number of survey items assessing parental encouragement. Future studies may want to examine multiple types of parental support and encouragement, as well as other mechanisms through which parents influence their children's participation in these behaviors such as behavior modeling. Additionally, future studies should assess parents' report of the encouragement and support that they feel they provide their child for healthy eating, physical activity, and dieting. Parents' and adolescents' report of the family environment are often quite discrepant [
      • van Assema P.
      • Glanz K.
      • Martens M.
      • Brug J.
      Differences between parents' and adolescents' perceptions of family food rules and availability.
      ], and understanding both perspectives can inform the development of intervention messages that are relevant to both parents and children. Finally, future longitudinal studies are needed to examine secular changes in parenting practices over periods longer than 5 years as it may take more time for societal changes to influence the ways in which parents and children interact around health topics.

      Conclusion

      The current study examined longitudinal and secular changes in parental encouragement of adolescents to eat healthy foods, be physically active, and diet to control their weight. These three parenting practices have been shown to play a role in the adolescents' participation in health behaviors that have a significant impact on their current and future weight and health status. Considering the decreases observed in adolescents' report of parental encouragement for healthy eating and physical activity between the middle and high school years, and among males between the high school and late adolescent years, efforts should be made to understand how parents can provide, and adolescents can perceive, high levels of support for healthy eating and activity during the transition into young adulthood. Further research is also needed to understand how clinicians, parents, and other adults talk about weight-related issues with adolescents, and how to make those conversations helpful to children and reduce the conflict and tension that is often experienced during conversations on these topics.

      Acknowledgments

      This study was supported by grant R40 MC 00319 (D. Neumark-Sztainer, principal investigator) from the Maternal and Child Health Bureau (Title V, Social Security Act), Health Resources and Services Administration, U.S. Department of Health and Human Services. The first author was supported by the Adolescent Health Protection Program (School of Nursing, University of Minnesota) grant number T01-DP000112 (PI: Bearinger) from the Centers for Disease Control and Prevention (CDC). Additional salary support for Dr. Laska was also provided by grant number K07 CA 126837 from the National Cancer Institute (NCI) . The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the CDC or NCI.

      References

        • Menschik D.
        • Ahmed S.
        • Alexander M.H.
        • Blum R.W.
        Adolescent physical activities as predictors of young adult weight.
        Arch Pediatr Adolesc Med. 2008; 162: 29-33
        • Ritchie L.D.
        • Spector P.
        • Stevens M.J.
        • et al.
        Dietary patterns in adolescence are related to adiposity in young adulthood in black and white females.
        J Nutr. 2007; 137: 399-406
        • Albertson A.M.
        • Franko D.L.
        • Thompson D.
        • et al.
        Longitudinal patterns of breakfast eating in black and white adolescent girls.
        Obesity (Silver Spring). 2007; 15: 2282-2292
        • Savage J.S.
        • Birch L.L.
        Patterns of weight control strategies predict differences in women's 4-year weight gain.
        Obesity (Silver Spring). 2010; 18: 513-520
        • Neumark-Sztainer D.
        • Wall M.
        • Guo J.
        • et al.
        Obesity, disordered eating, and eating disorders in a longitudinal study of adolescents: How do dieters fare five years later?.
        J Am Diet Assoc. 2006; 106: 559-568
        • Pearson N.
        • Biddle S.J.
        • Gorely T.
        Family correlates of fruit and vegetable consumption in children and adolescents: A systematic review.
        Public Health Nutr. 2009; 12: 267-283
        • Granner M.L.
        • Sargent R.G.
        • Calderon K.S.
        • et al.
        Factors of fruit and vegetable intake by race, gender, and age among young adolescents.
        J Nutr Educ Behav. 2004; 36: 173-180
        • Edlefsen M.
        • Reicks M.
        • Goldberg D.
        • et al.
        Strategies of Asian, Hispanic, and non-Hispanic white parents to influence young adolescents' intake of calcium-rich foods, 2004 and 2005.
        Prev Chronic Dis. 2008; 5: A119
        • Heitzler C.D.
        • Martin S.L.
        • Duke J.
        • Huhman M.
        Correlates of physical activity in a national sample of children aged 9–13 years.
        Prev Med. 2006; 42: 254-260
        • Kuo J.
        • Voorhees C.C.
        • Haythornthwaite J.A.
        • Young D.R.
        Associations between family support, family intimacy, and neighborhood violence and physical activity in urban adolescent girls.
        Am J Public Health. 2007; 97: 101-103
        • Trost S.G.
        • Sallis J.F.
        • Pate R.R.
        • et al.
        Evaluating a model of parental influence on youth physical activity.
        Am J Prev Med. 2003; 25: 277-282
        • Springer A.E.
        • Kelder S.H.
        • Hoelscher D.M.
        Social support, physical activity and sedentary behavior among 6th-grade girls: A cross-sectional study.
        Int J Behav Nutr Phys Act. 2006; 3: 8
        • Dowda M.
        • Dishman R.K.
        • Pfeiffer K.A.
        • Pate R.R.
        Family support for physical activity in girls from 8th to 12th grade in South Carolina.
        Prev Med. 2007; 44: 153-159
        • Neumark-Sztainer D.
        • Wall M.
        • Perry C.
        • Story M.
        Correlates of fruit and vegetable intake among adolescents.
        Prev Med. 2003; 37: 198-208
        • Larson N.I.
        • Neumark-Sztainer D.R.
        • Harnack L.J.
        • et al.
        Fruit and vegetable intake correlates during the transition to young adulthood.
        Am J Prev Med. 2008; 35: 33-37
        • Bauer K.W.
        • Larson N.I.
        • Nelson M.C.
        • et al.
        Socio-environmental, personal and behavioural predictors of fast-food intake among adolescents.
        Public Health Nutr. 2009; 12: 1767-1774
        • Bauer K.W.
        • Nelson M.C.
        • Boutelle K.N.
        • Neumark-Sztainer D.
        Parental influences on adolescents' physical activity and sedentary behavior: Longitudinal findings from Project EAT-II.
        Int J Behav Nutr Phys Act. 2008; 5: 12
        • Meesters C.
        • Muris P.
        • Hoefnagels C.
        • van Gemert M.
        Social and family correlates of eating problems and muscle preoccupation in young adolescents.
        Eat Behav. 2007; 8: 83-90
        • Dixon R.
        • Adair V.
        • O'Connor S.
        Parental influences on the dieting beliefs and behaviors of adolescent females in New Zealand.
        J Adolesc Health. 1996; 19: 303-307
        • Kluck A.S.
        Family influence on disordered eating: The role of body image dissatisfaction.
        Body Image. 2010; 7: 8-14
        • Neumark-Sztainer D.
        • Bauer K.W.
        • Friend S.
        • et al.
        Family weight talk and dieting: How much do they matter for body dissatisfaction and disordered eating behaviors in adolescent girls?.
        J Adolesc Health. 2010; 47: 270-276
        • Fulkerson J.A.
        • McGuire M.T.
        • Neumark-Sztainer D.
        • et al.
        Weight-related attitudes and behaviors of adolescent boys and girls who are encouraged to diet by their mothers.
        Int J Obes Relat Metab Disord. 2002; 26: 1579-1587
        • Fulkerson J.A.
        • Strauss J.
        • Neumark-Sztainer D.
        • et al.
        Correlates of psychosocial well-being among overweight adolescents: The role of the family.
        J Consult Clin Psychol. 2007; 75: 181-186
        • Neumark-Sztainer D.
        • Wall M.
        • Story M.
        • van den Berg P.
        Accurate parental classification of overweight adolescents' weight status: Does it matter?.
        Pediatrics. 2008; 121: e1495-e1502
        • Deforche B.
        • De Bourdeaudhuij I.
        • Tanghe A.
        • et al.
        Changes in physical activity and psychosocial determinants of physical activity in children and adolescents treated for obesity.
        Patient Educ Couns. 2004; 55: 407-415
        • Davison K.K.
        • Jago R.
        • et al.
        Change in parent and peer support across ages 9 to 15 yr and adolescent girls' physical activity.
        Med Sci Sports Exerc. 2009; 41: 1816-1825
        • Nelson M.C.
        • Story M.
        • Larson N.I.
        • et al.
        Emerging adulthood and college-aged youth: An overlooked age for weight-related behavior change.
        Obesity (Silver Spring). 2008; 16: 2205-2211
        • Lau R.R.
        • Quadrel M.J.
        • Hartman K.A.
        Development and change of young adults' preventive health beliefs and behavior: Influence from parents and peers.
        J Health Soc Behav. 1990; 31: 240-259
        • Lawrence R.G.
        Framing obesity: The evolution of news discourse on a public health issue.
        Harvard Int J Press Politics. 2004; 9: 56
        • Powell L.M.
        • Chaloupka F.J.
        • Bao Y.
        The availability of fast-food and full-service restaurants in the United States: Associations with neighborhood characteristics.
        Am J Prev Med. 2007; 33: S240-S245
        • Anderson P.M.
        • Butcher K.E.
        Childhood obesity: Trends and potential causes.
        Future Child. 2006; 16: 19-45
        • Neumark-Sztainer D.
        • Story M.
        • Hannan P.J.
        • Croll J.
        Overweight status and eating patterns among adolescents: Where do youths stand in comparison with the Healthy People 2010 objectives?.
        Am J Public Health. 2002; 92: 844-851
        • Himes J.H.
        • Hannan P.
        • Wall M.
        • Neumark-Sztainer D.
        Factors associated with errors in self-reports of stature, weight, and body mass index in Minnesota adolescents.
        Ann Epidemiol. 2005; 15: 272-278
        • Diggle P.J.
        • Heagerty P.
        • Liang K.Y.
        • Zeger S.L.
        Analysis of longitudinal data.
        Oxford University Press, New York, NY2002
        • Cohen J.
        Statistical power analysis for the behavioral sciences.
        2nd edition. L. Erlbaum Associates, Hillsdale, NJ1988
        • Little R.
        Survey nonresponse adjustments for estimates of means.
        Int Stat Rev. 1986; 54: 137-139
        • Story M.
        • Neumark-Sztainer D.
        • French S.
        Individual and environmental influences on adolescent eating behaviors.
        J Am Diet Assoc. 2002; 102: S40-S51
        • Hattersley L.A.
        • Shrewsbury V.A.
        • King L.A.
        • et al.
        Adolescent-parent interactions and attitudes around screen time and sugary drink consumption: A qualitative study.
        Int J Behav Nutr Phys Act. 2009; 6: 61
        • Larson N.I.
        • Story M.
        • Wall M.
        • Neumark-Sztainer D.
        Calcium and dairy intakes of adolescents are associated with their home environment, taste preferences, personal health beliefs, and meal patterns.
        J Am Diet Assoc. 2006; 106: 1816-1824
        • van Assema P.
        • Glanz K.
        • Martens M.
        • Brug J.
        Differences between parents' and adolescents' perceptions of family food rules and availability.
        J Nutr Educ Behav. 2007; 39: 84-89