The Effect of Social Cognitive Theory-Based Interventions on Dietary Behavior within Children

Obesity is defined as a condition of excess body fat, resulting from excessive energy intake that leads to serious health consequences, including increased risk for cardiovascular disease, type 2 diabetes, stroke and different types of cancer [1, 2]. It is commonly assessed by using Body Mass Index (BMI), which is one’s weight in kilograms divided by the square of one’s height in meters (kg/m2) [1].


Introduction
Obesity is defined as a condition of excess body fat, resulting from excessive energy intake that leads to serious health consequences, including increased risk for cardiovascular disease, type 2 diabetes, stroke and different types of cancer [1,2].It is commonly assessed by using Body Mass Index (BMI), which is one's weight in kilograms divided by the square of one's height in meters (kg/m 2 ) [1].
Many children today grow up in a sedentary world that promotes inactivity along with intake of calorically dense, nutrient poor foods [3][4][5].This excessive energy consumption, combined with physical inactivity has led to the global epidemic of childhood obesity [6].The World Health Organization [1] reports that childhood obesity is one of the most serious public health challenges of the 21st century, with an estimated 170 million overweight and obese children around the world (children are defined by being less than or equal to 18 years of age).According to the U.S. Center for Disease and Control [6], the U.S. alone spent an estimated $147 billion on obesity-related medical costs, nearly 9% of all U.S. health expenditures.
Causes of childhood obesity include environmental, behavioral and personal factors that often act in combination [7][8][9].Environmental factors include life at home, parenting style, peer influence and school/community setting.Behavior factors involve one's choice of foods and food acceptance, whereas personal factors include nutrition knowledge and self-efficacy, which is an individual's confidence in performing a particular behavior and overcoming barriers to that behavior [7,10].
excessive weight gain and future development of obesity-related diseases [11][12][13][14].Keep in mind however, childhood nutrition interventions are not a "one size fits all" matter.Programs must be tailored to specific ages and/or cultural groups and become incorporated into the family, school and community setting, in order to improve effectiveness [15,16].
Bandura's Social Cognitive Theory (SCT) is an interpersonal theory that emphasizes mutual interactions of persons, behavior, and environment [17].Accordingly, this theory proposes that environmental and personal characteristics influence behavior [14].Therefore, nutrition intervention studies have decided to use principles of Social Cognitive Theory (SCT) to measure one's ability to participate in beneficial nutrition behavior and explain how other variables, such as self-regulation and self-efficacy are essential to integrating healthier nutrition into lifestyles [9,10].
According to Bandura [17], nutrition interventions are more successful if they: 1. Strengthen individuals' knowledge of the topic, such as understanding the benefits of a healthy diet SCT is the one of the most commonly used theoretical frameworks in interventions to promote behavior change, however, no review of the literature examines the efficacy of nutrition interventions based on specific SCT concepts (i.e.cognitive, environmental and behavioral) on preventing childhood obesity and improving health behavior within children.This is important because poor nutrition habits are often observed among this population [1,18].Therefore, the aim of this review was to examine the effectiveness of SCTbased interventions based on improving health behavior within children around the world.

Methods
Articles were searched on Psych Info, PubMed and Social Services Abstracts using key terms such as "social cognitive theory" and "obesity" with a published date between January 1996 to September 2015.The primary search from each database combined yielded 308 articles that were further evaluated based on whether or not the title obtained the words, "children," and/ or "adolescents" and were also published between 1996 and 2015.After further review, 68 articles were read to determine whether or not they met the final inclusion criteria, which consisted of original studies that obtained at least 15 subjects and provided substantive information regarding social cognitive theory strategies and its efficacy on modifying health behavior for children, including better dietary choices and increased physical activity.The final selection yielded 16 articles.The efficacy of social cognitive theory components on improving health behavior in children were summarized (Table 1).Studies that used validated nutrition education techniques and/or questionnaires along with multilevel linear regression models were evaluated to compare SCT strategies to anthropometric and/or behavior modification outcomes.P values of <0.05 were considered statistically significant.All analyses in the reviewed studies were completed using SAS or SPSS software.

Results
The studies chosen and analyzed for this review focused on children's' (ages 4-18 years old) ability to learn nutrition knowledge, environmental effects on making better health choices such as increasing intake of fruits and vegetable intake and lowering intake of foods high in fat and sugar, improving self-efficacy and increasing physical activity and/or measureable outcomes such as BMI.Studies used either an intervention followed by a series of pre-and post-tests and/or questionnaires and/or a single administered questionnaire with no intervention.The purpose of each study was to determine statistically significant relationships between cognitive, behavioral and environmental factors with one's attitude and/or ability for participating in optimal health behaviors, including better dietary choices and improved physical activity (Table 1).

a. Cognitive Factors
Adequate nutrition knowledge is essential for an individual to assess their own diet quality, in order to compare it to accepted norms, especially in regards to social influence by peers and/or parents [12,13].However, it is unknown whether nutritional knowledge alone influences food choices and behavior [7,12].
A cross-sectional study conducted by Gracey et al. [12] sought to determine high school students' nutritional knowledge in relation to dietary patterns.Students were given a questionnaire including eight items on nutritional knowledge, and seven items on eating patterns; results showed that there was a significant relationship between students' food variety scores and their nutritional knowledge scores (p<0.05),indicating that if a student presented with a high nutritional knowledge score, s/ he would more like have more variety in their diet -hence more "balanced" nutrition.Studies also showed significant correlation between nutrition knowledge and dietary self-efficacy and better improvements in overall dietary behavior in children [19][20][21].
The purpose of the study conducted by Cortes et al. [11] was to understand the effect of nutrition education on changes in shopping practices among 20, low-income, Latino families.Nutrition education consisted of three to five home visits and a supermarket tour.Researchers analyzed grocery store receipts at the beginning and end of baseline and measured nutritional content.Findings indicated that families decreased the total number of calories (p=0.008)from baseline to post-education.
On the other hand, a randomized control trial by Kocken et al. [13] examined the effects of school lessons about healthy food on

The Effect of Social Cognitive Theory-Based Interventions on Dietary Behavior within Children
Copyright: © 2016 Hong et al. 303 children's self-reported beliefs and behavior regarding the purchase and consumption of soft drinks, water and extra foods, including sweets and snacks.In addition to the lessons, children were also introduced to lower-calorie foods, food labeling and price reductions in school vending machines.Results showed that students' knowledge on energy intake and portion sizes was significantly affected after implementing the lessons (p<0.01),however, there was so significant relationship between nutritional knowledge and influence on eating behavior.

b. Environmental Factors
Currently, many children live in environments that promote inactivity and the consumption of foods high in fat and sugar [3].Studies have reported the importance of environmental factors on influencing children's dietary habits [7,[16][17][18].Environmental factors can include school and community settings and/or parental and peer influence.However, research varies in identifying if environmental factors prove successful at improving children's self-reported healthy behaviors and decreasing risk of overweight or childhood obesity [3,12,15,22].
A cross-sectional study by Perez-Lizaur et al. [7] examined the correlation between personal and environmental factors and their relationship to children's fruit and vegetable consumption through use of a validated questionnaire (n=327).Researchers found that the environmental factors that influenced fruit and vegetable intake included the mother being responsible for cooking at home (p<0.02) and accessibility to fruit and vegetables (p<0.01).It's important to note however, that this study only observed correlations between factors; overall, this population still showed below recommended fruit and vegetable intake.Studies also have shown that interactive parent-student homework assignments and school policy offering more fruit and vegetable increased fruit and vegetable consumption in children [23,24].
Peer and parental influence serves as a potential factor in determining children's behaviors related to nutrition and health.A randomized control trial conducted by Taylor et al. [13] sought to evaluate a community-based intensive nutrition education project and its effect on improving nutrition related behaviors for Hispanic mothers of pre-school aged children through use of peer educators.Hispanic grandmother figures (abuelas), who have respected positions within the Hispanic family and community were chosen as peer educators to deliver nutrition education lessons (n=36).The study consisted of an evaluation group (n=337) and a control group (n=52).The program used pre-and post-tests to evaluate knowledge, skills and behaviors related to healthy lifestyles.Results confirmed that program participants significantly improved their nutrition-related knowledge and behavior by improving overall total knowledge/skill score from baseline, to post-intervention and 6-month follow-up (p<0.001) and being able to select and prepare healthier meals from baseline, to post-intervention and 6-month follow-up (p<0.001).
The school environment provides an ideal setting to promote healthy eating behaviors and discourage a sedentary lifestyle [3].In particular, research suggests that the school cafeteria proves influential in determining children's diet behavior, ultimately influencing children's' risk for obesity [18].A cross-sectional study by Cusatis & Shannon [18] guided by Bandura's Social Cognitive Theory, examined the relationship between adolescent eating behavior and environmental factors.After surveying 342 high school students, results showed that students who reported eating food from the cafeteria had significantly greater intake of fat and sugar with male students' fat intake (p<0.01) and sugar intake (p<0.02) and female students' fat intake (p<0.001) and sugar intake (p<0.01).Peer discussion at school about which foods are healthy improves self-efficacy for healthy eating of lower fat consumption (p<0.01) and more consumption of fruits and vegetables (p<0.001)[25].
As previously mentioned, BMI is used to identify risk for childhood obesity.Researchers seek to find if certain environmental factors increase children's risk for excessive weight gain, leading to overweight or obesity.Coleman et al. [22] conducted a randomized control study in order to examine the effect of a community-based, national health program, CATCH (Child and Adolescent Trial for Cardiovascular Health) on children's health.Participants included 474 control schools (224 girls, n=224 and boys, n=249) and 434 CATCH schools (girls, n=199 and boys, n=224).Primary health outcomes (overweight, BMI and waist-to-hip ratio) were measured at the third, fourth and fifth grade levels.Results concluded that girls in control schools had a significantly greater increase of overweight status from third to fifth grade (13%) compared to girls in CATCH

The Effect of Social Cognitive Theory-Based Interventions on Dietary Behavior within Children
Copyright: © 2016 Hong et al. schools (2%).In addition, boys from control schools also had higher increase in overweight (9%) compared to boys from CATCH schools (1%) from third to fifth grade.
A few years later, the same researchers, Coleman et al. [15] decided to test the effectiveness of a different health program delivered within the elementary school setting, except this time, with a focus on diabetes prevention along with parental involvement; primary outcomes included measuring parent's (n=38) and children's (n=44) BMI along with parent's selfreported eating behavior.Classes were composed of ten sessions, starting with 30 minutes of physical activity, followed by 1 hour providing lessons on healthy lifestyle and prevention of Type II diabetes.The child class lectures included educational materials and activities appropriate for each age group (0-5 years and 6-13 years); parents also participated in separate lectures with similar class topics.Then, BMI was measured at the beginning and end of the 10-week intervention for all children and parents by measuring weight in kilograms and height in centimeters.Results showed that there was no significant change in BMI for either parents or children from baseline to the end of the program.However, parents did report eating more servings of vegetables after participating in the program (p<0.01).

c. Behavioral Factors
Another component of Bandura's Social Cognitive Theory, behavioral factors including the cornerstone to Bandura's theory, self-efficacy [17].Self-efficacy includes one's belief in themselves to accomplish certain tasks [17].According to Bandura, self-efficacy is a central construct that is integral to the interrelationship between personal, environmental and behavioral factors [6].Of importance, research shows that selfefficacy is correlated with dietary habits within children including improvement in self confidence in choosing more healthful foods and increasing fruit and vegetable consumption [7,9,18,26].
Rinderknecht et al. [9] conducted a 7-month intervention study in order to improve dietary self-efficacy of children ages 5-18 years old.Researchers hypothesized that the nutrition intervention would improve children's dietary self-efficacy and decrease their fat and sugar intake compared to children who had no improvement in self-efficacy.154 participants completed a pre-and post-intervention questionnaire and were measured for height, weight and BMI.Results showed that children exhibited moderate levels of dietary self-efficacy at baseline, with no variation in BMI; the nutrition intervention significantly improved the self-efficacy of children ages 5-10 years old (p<0.003)-especially for those children who were already obese (BMI > 95 th percentile for age, p<0.02).However, the intervention was not successful among children ages 11-18 years old and did not decrease fat/sugar intake.Researchers propose that this population may be constrained by peer influence on food choices and use of food as a reward [9].
On the other hand, Cusatis & Shannon [18] examined the relationship between children's diet behavior and reported selfefficacy.242 high school students completed a questionnaire regarding fat and sugar intake and personal factors including subject's body image, self-esteem and self-efficacy for healthy eating behavior.Results showed that for males, were was a significant relationship between fat and sugar intake and student's self-efficacy (p<0.0001).For females, only sugar intake was significantly associated with perceived self-efficacy (p<0.008).
A randomized control study by Najimi & Ghaffari [14], surveyed the effect of SCT-based nutrition education on fruit and vegetable consumption among 4 th grade students during a 12week period.Student were randomized into intervention (n=68) and control groups (n=70), with data collected at the beginning and end of the 3-month intervention.Results revealed that the intervention group had significantly improved scores regarding self-efficacy in difficult situations (p=0.04) and self-efficacy in selecting fruits and vegetables (p=0.01).More importantly, they also found that the intervention group consumed significantly more fruits and vegetables compared to control, postintervention (p<0.001).These results support Bandura's theory that self-efficacy plays a role in influencing behavior, especially self-efficacy specific for healthy eating as a significant predictor of actual eating behavior.

Discussion
The prevalence of childhood obesity is continuing to rise over years and it has become a global issue [27].Causes of childhood obesity can be categorized into behavioral, environmental and personal factors, which coincide to components found in Bandura's Social Cognitive Theory (SCT).This theory not only seeks to define variables leading to behavior change but also seeks to explain the relationship that exist among them.The purpose of this review was to examine the effectiveness of nutrition interventions based on individual SCT components (environmental and personal variables) in improving dietary behavior and health outcomes to prevent obesity within children ( 18 years old).

a. Cognitive Factors
Bandura defines knowledge as the basis for behavior change.Although the studies done by Gracey et al. [12] and Cortes et al. [11] noted a correlation between food choice and nutritional knowledge, study by Kocken et al. [13] found nutrition knowledge increased after being exposed to nutrition education, however there was no significant relationship with nutrition knowledge and actual dietary behavior.These varying results, suggest that knowledge alone may not be responsible for changing children's eating behavior.This could be due to confounding variables, including social environment and self-esteem along with the risk self-reporting error.

b. Environmental Factors
When examining the effect of environmental factors on behavior change, results revealed that environmental factors such as schools and family may provide as an ideal setting to promote healthy eating behaviors, but might not be effective in preventing excessive weight gain.Studies found that children's

The Effect of Social Cognitive Theory-Based Interventions on Dietary Behavior within Children
Copyright: © 2016 Hong et al.
fat and sugar intake was significantly correlated to reporting eating food from the school cafeteria; meanwhile, nutrition interventions that used peer nutrition education proved to be successful in modifying food purchases and preparations by children's families [16].On the other hand, other school-based interventions showed no improvement in children's BMI, one of the main determinants of overweight, obesity and risk for obesity [15].

c. Behavioral Factors
While looking at behavioral factors such as self-efficacy in determining nutrition-related behavior change, there appeared to be a positive correlation between one's perceived selfefficacy and one's ability to choose healthy foods and participate in healthy activities.However, there does seem to be slight differences between males and females regarding self reported self-efficacy.Study by Cusatis & Shannon [18] showed significant relationship for self-efficacy and sugar intake among male and female high school students, but only a significant correlation between self-efficacy and fat intake among males.This suggest that future research should consider gender differences when determining nutrition interventions.
In conclusion studies from this paper appear suggest that environmental, cognitive and behavioral factors act together to influence children's dietary conduct in regards to food choices and healthy lifestyle choices.Further research should be done to better control for confounding variables in order to determine if any of these individual factors alone can change nutrition behavior.Once better understood, factors from Bandura's social cognitive theory could prove as useful when developing nutrition programs for children in order to improve food choices and decrease children's risk of obesity.

2 . 3 .
Improve environmental factors, including family/peer social support Encourage self-efficacy, by fostering confidence in performing a specific behavior 4. Develop the use of self-regulatory behaviors by means of modeling behavior and interactive learning 5. Interventions are appropriately tailored for demographic groups.

Table 1 :
Studies Examining Effects of Cognitive, Behavioral and Environmental Components on Health Behaviors

Reference/ Research Design Sample Location/ Duration Environment Component Cognitive Component Behavior Component Results
• Self-esteem & Self-image questionnaire• Self-efficacy scale • FFQ• Males: High levels of selfefficacy was associated with low consumption of high-fat and high-sugar foods (p<0.001)

The Effect of Social Cognitive Theory-Based Interventions on Dietary Behavior within Children
BMI=Body Mass Index, C=Control, F=female, FFQ=Food Frequency Questionnaire, f/u=follow up, FV=Fruits and Vegetables, I=Intervention, M=Male, MVPA=Moderate to Vigorous Physical Activity, NE=Nutrition Education, PA=Physical Activity, RCT=Randomized Control Trial, SES=Socio Economic Status