August 2008 Issue

Youth Eating and Exercise: A Bioecological Perspective
By Terri Lisagor, EdD, MS, RD, and Scott W. Plunkett, PhD
Today’s Dietitian
Vol. 10 No. 8 P. 32

Childhood obesity isn’t the result of a single factor, so it stands to reason that not one element can reverse the trend. Collaboration among health professionals, families, and all who influence youth behaviors is key!

Escalating and disturbing trends are impacting the long-term health and well-being of U.S. youths. Childhood obesity has more than doubled in children and adolescents over the last 30 years, and early excess weight is linked to later obesity. More than 9 million U.S. children over the age of 6 are considered obese.1,2 The obesity epidemic has even hit infants: Between 1980 and 2001, the number of overweight infants increased by 74%.3

Extreme weight loss behaviors have also become more widespread among youths.4-6 Approximately 13% of fifth- to 12th-grade girls and 7% of boys exhibit some form of disordered eating behavior (eg, bulimia, anorexia), and 18% of high school females and 8% of males have skipped eating for more than 24 hours to lose weight.7

Youths who are overweight, get little exercise, or demonstrate disordered eating behaviors are likely to continue these behaviors into adulthood; have an increased risk of heart disease, diabetes, and early death; and have increased emotional problems (eg, lower body image satisfaction, lower self-esteem), which can lead to depression and suicide.4,8-11

Bronfenbrenner’s bioecological model recognizes that individual qualities in conjunction with environmental influences (eg, family, community, society) can shape youth eating and exercise.12 Although genetics predispose an individual to obesity, environmental influences significantly affect energy and nutrient and dietary intake.13-15 Figure 1 shows influences on eating and exercise in various ecological contexts. According to the bioecological framework, prevention and intervention must target the individual, as well as multiple environmental influences, to be most effective.16

Family Context Related to Eating and Exercise
The bioecological model recognizes the family as the primary context in which development takes place. Numerous family factors are linked to youth eating and exercise. A connection between parent and child obesity is not surprising given the genetic influence and behavioral predisposition. For example, parents with higher body fat are more likely to have children who have a preference for dietary fat.17

Youths learn behaviors primarily through parental modeling. For instance, toddlers are more likely to try new foods when they see their parents eating them.18 Additionally, parents generally purchase and prepare foods they like; hence, these foods also become part of children’s diets.19 Parental modeling of physical lifestyles (eg, sedentary vs. highly active) also influences children.7,13 Parents’ actions, such as purchasing video and computer games, may also indirectly encourage sedentary behaviors in children.

Furthermore, family eating rituals may involve eating at the dining room table or in front of the television, serving large portions, leaving the table only when everyone has finished eating, grabbing snacks between meals, and so on. Children are likely to continue these patterns into adulthood. Time considerations also impact youths’ food intake and exercise patterns (eg, sleeping longer instead of eating or exercising, grabbing fast food, and/or eating more prepackaged convenience foods).20

Parental neglect, lack of parental care, a critical family environment, and/or low family cohesiveness can contribute to unhealthy eating habits and increase the risk of eating disorders.21-23 Youths may turn to aberrant eating behaviors (eg, bingeing, vomiting) as a coping strategy or as a way to connect with and/or elicit sympathy from others.

School and Peer Influences
Schools can also influence youths’ eating and exercise behaviors (see Figure 1). Of course, students can learn health in the classroom, but nonverbal actions speak loudly: What foods and beverages do schools serve children? What snacks do they sell in machines on campus? What physical activities does the school provide and promote?

In an effort to monitor the rate of childhood obesity, the National Center for Education Statistics (NCES) within the Department of Education conducts surveys of elementary schools, evaluating the availability of foods outside of school meals, as well as opportunities for students to engage in physical activity. As evidenced from its 2005 survey, there is decreasing support for physical exercise in schools. Only 17% to 22% of public elementary schools provided daily physical exercise, and nearly one half had physical exercise only one or two days per week.24 Grunbaum et al reported that the percentage of high school students enrolled in physical exercise classes dropped from 41.6% in 1991 to 28.4% in 2003.25 Further, although many states have implemented physical exercise standards for schools, the Institute of Medicine has concluded that schools do little to enforce these standards.26

Interestingly, while school food programs are supposed to meet federal nutrition guidelines, students can purchase less nutritious foods (eg, from vending machines, snack bars, a la carte meals, and student stores), and these foods do not have to meet the standards.27 Since children’s taste preferences determine which foods they consume, this often translates into higher calorie, fat, and saturated fat intake.

Peers provide a social support system that can be powerful for making behavioral changes.28 Peers, for example, can stimulate or decrease an individual’s physical activity levels. Research has found that an adolescent’s best friend has more influence  over physical activity than his or her parents.29 Other studies have determined that when overweight youths were with peers and friends, they were more likely to engage in more intense physical activity.29,30

Interplay of Society and Family in Relation to Eating and Exercise
Societal influences can also impact  youth eating behaviors, which home influences can either reinforce or buffer (see Figure 1). Cultural and/or religious practices in the home may affect food selection and preferences (eg, spicy foods, fish/plant-based diets) and eating rituals. Culture can also influence body image perceptions.21 Cultural standards that equate slenderness with beauty may be buffered when families don’t perpetuate the cultural value or validated when families reinforce the cultural messages.

Media and television viewing in the home can exert powerful influences over a child’s health and well-being.31 Children are increasingly tied to the computer or “glued to the tube,” with the average child watching more than 40,000 commercials per year.28 Besides being a sedentary activity, television viewing increases calorie intake since during children’s television viewing time, the majority of advertisements are for foods that are high in fat, sugar, and sodium.31-34 Research has demonstrated that children consume 167 extra calories per hour of television watched, most coming from high-calorie, low–nutrient-dense foods that were advertised on television.34

Another societal influence is the trend toward increased portion sizes in food establishments. As people eat foods prepared outside the home more often, they consume more calories, total fat, and saturated fats.35,36

Collaborative Approach to Promote Health in Individuals and Families
The bioecological perspective recognizes the interplay between youth attributes, family characteristics, and other contexts in relation to youth eating and exercise (see Figure 1). Hence, it provides a holistic view for multidisciplinary collaboration for prevention, intervention, and policy making. How can dietitians, family practitioners, other child and health professionals, and policy makers address this problem? The answer becomes clearer when acknowledging the individual strengths of each group and recognizing “power in collaboration.”

Most health professionals realize that obesity and eating disorders are not just physiological or psychological in nature. Dietitians, pediatricians, and other child healthcare providers may not be trained to deal with the psychological problems often associated with obesity and eating disorders; community counselors, psychologists, and family practitioners may not have adequate knowledge of the physiological aspects of obesity and eating disorders; and psychologists and physicians may not have the expertise to address the nutritional components. Hence, health professionals should recognize the efficacy of a multidisciplinary team approach in developing interventions.37-39 Such an alliance can and should deliver a consistent message to parents and children that will shape healthier lifestyle habits for youths.

Research has found that treating parents of obese children can actually be more effective than treating the children directly. Also, research indicates that behavioral, family-based treatment for both the children and parents is most effective in diminishing obesity and/or maintaining weight loss over time.40-42

Collaborative intervention should include education about healthy eating and exercise in an effort to facilitate change. Professionals should suggest specific activities that parents can do with their children to ensure healthy eating and exercise, such as self-monitoring charts to record daily food intake, exercise, weight, television viewing time, and computer and video game time. They should also develop strategies to assist parents in providing strong modeling for their children, including how to use social reinforcements, especially conjoint/reciprocal reinforcement where both the youths and their parents reinforce each other’s healthy eating and/or exercise behaviors. Additionally, families should be taught how to use behavioral contracts and nonfood reinforcement protocols with clearly articulated responsibilities and goals. 

Professionals could assist families in using associative conditioning (ie, repeated exposure to foods should eventually result in the flavor of those foods becoming associated with satiation cues involved in digestion and absorption).19 For example, every time a child craves high-calorie, high-fat foods, he or she should initially eat nutrient-dense foods to satisfy the body’s satiation cues with healthier foods. If a child always drinks sodas when thirsty, parents could be encouraged to provide him or her with water; hence, the healthier option would satisfy the thirst.

Professionals should work with family members who are willing to make changes. If the entire family is not ready to change, the family could then be referred to motivational counseling or therapy. Finally, the professionals should encourage all involved in the day-to-day caretaking of the child to provide a consistent message regarding healthy practices.

The Role of Parents and Primary Caregivers in Promoting Healthy Practices
Parents and primary caregivers are key players in collaborative efforts to promote healthy eating and exercise habits in youths. Hence, successful prevention and intervention efforts rely on parents being active participants. Each helping professional should provide strategies to parents to promote healthy lifestyle choices.

Professionals could recommend that parents let children participate in nutritious food shopping and preparation. Parents who involve children in these activities help them take ownership of and become involved in healthy eating behaviors, thus shaping more positive lifestyle behaviors.43 Parents should be encouraged to make healthy food more available and convenient while limiting the availability of unhealthy food options.

Parents can also repeatedly expose their children to new foods. Research has found that food often has to be placed on the plate or menu several times before children try it; five to 10 exposures are often required before youths learn to like a new food.19

Help parents understand their role as nutrition and exercise role models. Professionals can assist parents in understanding the benefits, for example, of walking short distances instead of driving, exercising in the morning, and eating healthy foods. Parents should limit children’s access to television, the computer, and video games to reduce their exposure to food advertising and provide more opportunity for active behaviors. One way parents and caretakers can do this is by joining in the activity. Additionally, professionals should suggest that families plan activities involving exercise, and parents should make exercise equipment available and buy toys or gifts that inspire exercise.44

Encourage parents to establish mealtime routines (eg, eating together at the dining room table, not in front of the TV). Professionals may also recommend that parents put food on the plate before bringing it to the table rather than serving the meal family style. Hence, youths must ask for more food and/or get up to get more food. Also, smaller portion sizes should be served because people become accustomed to eating larger amounts of food when larger portions are provided. Another family meal rule should be that everyone must stay at the table until all family members are finished eating. This might slow children’s consumption rate.

Parents should also contact their child’s school to ensure that recess is part of his or her day. Lastly, and most importantly, parents must provide their children with love and support, regardless of their weight.

Further Implications and Conclusion
Any discussion about the health and well-being of children highlights the importance of education, collaboration, cooperation, and teamwork, involving all spheres of the bioecological framework (see Figure 1), including the media, schools, peers, public policy, the physical environment, and society in general.

Because so many youths are exposed to the commanding messages of television and advertising, there is tremendous potential for changing to more health-oriented media messaging.45 Restaurants could offer portion sizes that are more realistic and less super sized, as well as more nutritious choices, and promote these in ways that would appeal to younger audiences. Nutritional information could be made more accessible to parents and other caregivers.

School districts, as well as individual schools, have a unique opportunity to deliver health-based messages in the classroom and provide the opportunity for children to apply what they learn by offering healthy foods during the school day and supporting and encouraging physical activity.1

Recognizing the influence of peers, emphasis can be placed on encouraging running clubs, “pick-up” basketball games, cooking classes, etc, which can build positive social networks for young people.

Public policy can be shaped at community, local, state, and federal levels by each individual. And the influence of individuals can be especially effective when people work together to make their collective voices heard. For example, are there places for children to safely walk, bike, run, or skate? And what about community parks? Community coalitions can collaborate with all levels of government to promote healthy lifestyles.


All elements of society must work with one another and with parents and/or child care to supply the best possible support for children. Together we can help deliver a consistent message to parents and children that will shape healthier lifestyle habits for youths.
— Terri Lisagor, EdD, MS, RD, is an assistant professor of nutrition and food science at California State University, Northridge, an RD in private practice, and a lecturer at the University of California, Los Angeles School of Dentistry.

— Scott W. Plunkett, PhD, is an associate professor in the departments of family and consumer science at California State University, Northridge. He investigates family, peer, school, and neighborhood contexts in relation to adolescent outcomes in multicultural communities.

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