Specific Aims There is much in the scientific literature on individual and societal level determinants of obesity among young people. While addressing these proximate1,2 and distal factors3,4 is crucial to obesity prevention and health promotion, there is emerging evidence that interpersonal relationships, specifically, friends are associated with eating and physical activity (PA) behaviors and obesity.5-10 However, the mechanisms by which friendship networks are involved in eating and PA are not well understood. Social network research in public health describes how health behaviors and outcomes are shared, transferred, and influenced through social ties. By not having a better scientific grasp of the role of friendship networks in weight-related behaviors and outcomes, we may be missing critical points for behavioral and obesity prevention. Life as a college freshman is a period of immense change, which has been shown to result in increased risk for excessive weight gain,11,12 declines in PA levels13,14 and overall diet quality.15,16 As a result of identity formation and changes in interpersonal influences, college is a critical time in establishing weight-related behaviors that are carried into adulthood.17,18 College freshmen are vulnerable as they begin to make choices independent from their parents and become more aligned with their friends. Students living in dormitories are of particular interest since these students are living, studying, eating, and playing with friends. This study aims to capitalize on the unique opportunities at Arizona State University (ASU), the largest public US college with one of the most diverse student populations(40% low-income; 40% minority), to qualitatively and empirically assess the role in which friendship networks are involved in nutrition and PA behaviors and risk for excess weight gain among college freshmen. Using qualitative focus groups and cell phone-based ecological momentary assessments (EMA), survey data, and secondary data with ASU freshmen living in dormitories, this study will longitudinally track how friendships are created and better describe the causality by which friends are associated with weight-related behaviors and outcomes. Aim 1: Determine the mechanism(s) by which friends have an impact on freshmens eating and PA behaviors and weight overtime. There is inconsistency in the literature about what portion of the relationship between friends weight related behaviors and outcomes can be attributed to shared routines or environments, social learning about weight-related activities or ideal body size, social pressure, friend selection, friendship ideals, shared access, norms, and influence. Four research questions (RQ) will guide us in addressing these gaps through Aim 1: RQ 1: What are young peoples insights on how their friends influence their eating, PA, and weight during their freshmen year? RQ 2: What is the association between friendship networks eating, PA, and weight throughout freshman year? RQ 3: Why do youth engage in certain eating and PA behaviors when friends are present? RQ 4: How do changes in friendships (new friends) alter these associations? A deeper understanding of young peoples perceptions of how friends are involved in their behaviors is needed through qualitative focus groups research (formative phase), which, to our knowledge, has not been previously studied. Strong longitudinal data on the changes that occur among friends is also needed to better understand the causality between these relationships. Thus, mechanisms of friends on nutrition and PA behaviors and weight status will be tracked repeatedly (6 times) within a school year using an EMA cell phone application (app) distributed to entire dorms of freshmen at ASU (epidemiological phase). Aim 2: Explore the contextual factors related to behaviors among of friendship networks over time. With the multiple data collection approaches, we will be able to answer if there are key environments and times throughout the day in which college freshmen friends spend more time eating and being physically active together, informing when and where interventions would be best developed. We will explore how associations differ among college roommates (randomly assigned at ASU) compared to the associations in the larger friendship network, and whether there are demographic differences apparent in associations among friends behaviors and weight status over time. Three research questions will guide us in addressing Aim 2: RQ 5: Are there times of the day or places in the environment that mediate the relationship between friends eating and PA behaviors? RQ 6: How do associations vary among different types of friendships, including roommates, close friends, friend groups? RQ7: How do gender and race/ethnicity moderate associations? These research questions will answer if some mechanisms more salient for some friends or environments compared to others. The proposed study will address critical gaps in the literature by simultaneously exploring behaviors among friends using multiple methods and datasets, each complementing the other. This study will greatly enhance knowledge about how friendship networks impact weight-related behaviors and outcomes and will inform the development of interventions with college students. The proposed study provides a nexus in which a young investigator will benefit from expertise and cutting-edge research of mentors/collaborators from multiple disciplines. The experience and knowledge gained from the proposed study builds on the PIs previous research, and prepares her with a jumping point for a career in assessing and intervening on social influences of nutrition and PA outcomes. All of these factors will contribute to the successful implementation of the study, innovative and useful results to guide interventions, and wide dissemination of findings for maximal impact.
Effective start/end date9/20/138/31/16


  • HHS-NIH: Office of the Director (OD): $1,840,954.00


eating behavior
cell phone
technical literature
identity formation
social learning
health behavior
health promotion
social network
low income
public health