College campuses' influence on student weight and related behaviours: A review of observational and intervention research

3.1.1 Nutrition-related environments/policies

Campus dining systems present an opportunity as well as a potential barrier for promoting student nutrition. Cross-sectional studies show that students on an unlimited access (UA) meal plan (as opposed to a point system plan or no plan) have higher fruit, vegetable, dairy and meat (type unspecified) consumption.^{25, 26} However, UA meal plans are also associated with consumption of high-fat, energy-dense foods, such as pizza and fried foods.²⁵ UA dining systems may provide an efficient way to feed large student populations and encourage greater consumption of healthful options; however, such systems may also contribute to overconsumption and student weight gain.

In addition to meal plan type, on-campus housing location has been associated with student eating habits, as well as PA and weight. In a large, natural experiment of randomized first-year housing, Kapinos and Yakusheva²⁷ reported that male students who lived in buildings with on-site dining facilities ate more meals and snacks than males who did not live in buildings with dining facilities. Female students who lived in buildings with on-site dining gained more weight and reported fewer exercise bouts per week than females who lived in buildings without on-site dining. In a subsequent analysis, the researchers reported that female students living near a dining hall that was closed on weekends gained 0.45 kg less (1 fewer pound) over the year, on average, than female peers living near dining halls open 7 days per week.²⁸ The campus built environment had no significant effects on male student weight change, even though male eating behaviours were significantly influenced.^{27, 28}

In contrast to students housed on campus, students who live off-campus face a different set of nutritional challenges. One reason for this may be that off-campus students are often not on a school meal plan. One cross-sectional study found that students living off-campus exhibited significantly less fruit, vegetable and dairy consumption than on-campus residents.³⁰ Students who lived off-campus were also more likely to have overweight/obesity and to consume more alcohol than those who lived on campus or with parents.³⁰ Additional cross-sectional research has shown that students living off-campus (including those who lived with family) had less healthy home food availability, ate fewer meals and had poorer dietary intake compared with students living on campus, regardless of socioeconomic status.²⁹ This suggests that exposure to on-campus food environments may offer advantages relative to off-campus environments in terms of healthy dietary behaviours. However, students living on campus have been found to consume more ice cream and grain-based desserts than students living off-campus alone or with peers.²⁹ Collectively, these findings suggest that on-campus meal plan enrolment offers nutritional advantages for students; however, students likely need support navigating campus food options.

Research also speaks to the importance of campus food environments that extend beyond the dining hall and into the dorm room. An observational study of student dorm snacks found that students at a large public university had an average of 47 food/beverage items in their room, totalling 22 888 calories per student.³¹ More than 70% of students had each of the following items: salty snacks, cereal/granola bars, main dishes, desserts/candy and sugar-sweetened beverages. There were no significant differences in the number of food/beverage items by students' meal plan type, sex, class year or roommate status. Notably, the items reported as being purchased by parents were generally higher in calorie and fat content than the items purchased by students.³¹

Energy-dense foods contribute to overeating and weight gain due to their high palatability.⁴¹ Fast food chains and snack companies have made high-calorie foods inexpensive, convenient and widely available to undergraduate populations. For example, many franchises partner with campus administrations to open kiosks at strategic locations on campus and use branding to appeal to student values (e.g., social responsibility and health).⁴² On-campus fast food kiosks can be integrated with dining system payment options (e.g., ‘flex points’), offering students easy access through their meal plan. Although fast food is pervasive and easily accessible on and around college campuses, there is some evidence that student fast food consumption might be reduced via manipulation of meal plan components. One cross-sectional study found that students with higher on-campus meal allowances ate less fast food, and students who had ‘flex dollar’ access to fast food restaurants ate more fast food.³² This suggests dining plans that offer more dining meals and limit use of points for restaurant purchases might reduce student fast food consumption. However, it may also be that students who prefer fast food are more likely to purchase flex dollars. Longitudinal studies are needed to elucidate causality. Future interventions could explore the impact of limiting dining point use to designated ‘healthy’ items on campuses where restaurant foods are available to students via points.

Finally, financial burden and food insecurity may contribute to weight gain among college students.⁴³ Although research does not show a link between food insecurity and weight in young men, food insecure women have higher average BMIs than women who are food secure.³⁴ According to one article, which pooled survey data from multiple campuses across the United States, more than 50% of both 2- and 4-year undergraduates may be affected by some form of food insecurity.³³ Common food security challenges reported by students included being unable to afford balanced meals, having food not last and being unable to buy more and having to cut the size of meals or skip meals altogether because there was not enough money for food.³³ Food insecurity, which has received relatively little attention on college campuses in the past, is currently becoming a top priority at many institutions.⁴⁴ For example, York College/City University of New York (CUNY) and Community College of Philadelphia have recently opened innovative on-campus food pantries for student use.^{45, 46} Research is needed to more fully explore the relationship between student food insecurity and health outcomes (e.g., dietary behaviours and weight), as well as to test the effectiveness of food security initiatives in promoting social–emotional benefits, academic achievement and other important student outcomes. Feasibility studies should also be conducted to advance understanding of barriers and facilitators to implementation of such programmes.

3.1.2 PA-related environments/policies

Although factors influencing college student dietary behaviours have received attention, few studies have focused on environmental determinants of undergraduate PA. In the natural experiment conducted by Kapinos and Yakusheva,²⁷ researchers found that first-year females living in a residence hall with on-site dining engaged in intentional exercise less frequently than students who did not live in buildings with dining facilities. Additionally, living near a gym was positively associated with frequency of exercise bouts per week in female students, whereas living closer to central campus reduced females' exercise frequency.^{27, 28} The researchers hypothesized that the reduction in exercise with greater proximity to central campus may have been a result of less time spent walking to academic buildings and student service facilities. No significant associations between housing location and PA behaviour were seen in male students, but this may be due to the small male sample size. Notably, men and women exhibit heterogeneous PA behaviours,^{10, 47-49} and similar projects should examine the influence of campus structure on PA outcomes in college men using adequately powered studies. Such findings could inform future campus renovations and/or building use decisions.

Implementation of required PA coursework has been explored as one policy avenue for schools to promote student PA. From a theoretical standpoint, researchers have argued that PA requirements are likely to promote accessibility, cultivate positive PA experiences and promote life-long PA habits among students.^{50, 51} However, recent studies examining associations between PA course requirements and student PA levels are sparse.^{51, 52} Although more research directly examining PA outcomes in the context of PA course requirements is still needed, evidence suggests there may be other benefits associated with PA requirements. For example, a cross-sectional study among 612 university students revealed that female students' motivation for enrolling in a PA course was associated with university PA course policies.³⁵ In this study, female students were more likely to report intrinsic motivations (e.g., to have fun) for enrolling in PA courses at a university with a PA requirement and to report extrinsic motivations (e.g., to improve fitness and to exercise regularly) at a university with an elective PA course policy. In contrast, male students frequently reported intrinsic motivation under both conditions.³⁵

More recently, results from a 2018 cross-sectional study found that, in the presence of PA course requirements, college seniors reported more internalized motivation (e.g., exercise is fun and exercise is important) and less amotivation (e.g., exercise is a waste of time and exercise has no point) for PA than did first-year students.³⁶ These findings suggest that students who were initially amotivated, but compelled to engage in PA by a course requirement, may have learned that they enjoyed PA, felt they were good at PA or came to value outcomes associated with PA. In short, limited research suggests that implementing campus PA requirements might positively impact students' motivation for PA and reach students less likely to engage in PA on their own.⁵¹ However, longitudinal research is needed to confirm this hypothesis and to directly examine PA behaviours as an outcome.

Preliminary research suggests PA requirements have the potential to improve student PA levels. However, evidence from a 2012 study suggests that there have been considerable declines in the number of institutions with physical education requirements from the 1920s/30s through 2010 (97% vs. 40%).⁵³ It is not well understood why institutions are dropping these requirements, although some researchers hypothesize that funding structures may play a role.⁵⁴ Future research should examine the factors influencing institutions to drop physical education requirements, as well as potential incentives to encourage schools to (re-)institute them. Future studies should also specifically examine classes that designate time for performing physical activities, given that prior studies have combined classes designated for performing physical activities and classes that provide non-active, conceptual physical education instruction.⁵³

Few observational studies have explored the impact of walkability and/or bikeability of campus environments, although available evidence suggests such measures are associated with student PA.^37-40 Walkability and bikeability measures take into account aspects of the safety, quality and comfort of the built environment, such as traffic levels, adequate lighting, network connectivity of sidewalks/walking paths, sidewalk surface condition and width, mixed land use and aesthetic design.⁵⁵ Three cross-sectional studies have reported a positive association between students' perceived walkability/bikeability of their campus environment and their PA levels, including self-reported walking,^{38, 39} self-reported active transportation,⁴⁰ self-reported total PA⁴⁰ and objectively measured step counts.³⁸ One study also reported that walkability/bikeability was inversely associated with student BMI.³⁹ A longitudinal study of built environment changes at a university in Hong Kong using student walking diaries also revealed positive findings, supporting a potential causal link between the built environment and student activity levels.³⁷ For example, the study reported that an increase in pedestrian network connectivity was associated with longer walked distances and increased likelihood of walking, increased population density resulted in longer walked distances and an increase in bus services resulted in greater walked altitude compared with student activity before these changes occurred.³⁷

3.2.1 Dining-based interventions

Nutrition labelling policies have been well-studied and offer potential for broad impact on college campuses. Studies show that label information is associated with improved student dietary choices and decreased caloric intake.^56-63 Additionally, labels that provide ‘contextual’ information (e.g., traffic light colours and exercise equivalents) may be more effective than ‘textual’ calorie information.^{57, 59, 63} Intervention setting can also influence student use of nutrition labels. Studies conducted in dining halls and quick service restaurants show largely positive results,^56-62 whereas studies of vending machine snack choices show few effects.^{78, 79} Research examining reasons why student behaviour may be resistant to change in the context of vending labelling is warranted. Feasibility studies for implementing vending labelling interventions in college contexts may also be of use, as previous research indicates large vending suppliers are resistant to change.⁷⁹

In addition to nutrition labelling, general marketing of healthier items may be effective in promoting students' healthy eating. One serial cross-sectional study found that average student fruit intake increased following a 9-day cafeteria-based point-of-selection fruit marketing campaign.⁶⁴ Another intervention study used an array of marketing elements (e.g., point-of-selection indicators, signs, table tents, flyers and benefit-based messages) to promote 10 healthy food items for 3 weeks.⁶⁵ Student self-reported consumption of low-fat salad dressing and cottage cheese increased significantly from baseline, and a trend towards more frequent fruit consumption was also reported. However, no significant changes were reported in student consumption of other promoted items, including steamed vegetables, chicken breast, tossed salad, skim milk, whole grain bread or yogurt, and deli sandwich consumption significantly decreased, leaving some uncertainty about the effectiveness of the intervention as a whole.⁶⁵

A recent study using ‘indulgent descriptions’ (e.g., twisted citrus-glazed carrots) to label healthy foods in comparison with a ‘healthy positive label’ (e.g., smart choice vitamin C citrus carrots), a ‘healthy restrictive label’ (e.g., carrots with sugar-free citrus dressing) or no label (e.g., carrots) found that indulgent descriptions had a significant effect on both the number of diners selecting the vegetable and the amount of vegetable consumed. For example, indulgent labels resulted in 25% more people selecting the vegetable than in the basic condition and 41% more people than in the healthy restrictive condition.⁶⁶ Further work in the area of taste-focused labelling has revealed sustained positive findings across several campus settings, and researchers now claim that this tactic may be a low-cost strategy to increase healthy food consumption among college students.⁶⁷

Lastly, a campus-wide social marketing campaign Energize your Life! used a number of tactics (e.g., brochures, posters, table tents, weekly demonstrations, food service policy changes and increased fruit availability) to increase student fruit intake on a community college campus.⁶⁸ The intervention lasted for 2 months; however, permanent food service policy changes also resulted from the intervention (i.e., fruit offered in vending machines and fruit cups offered as a substitute for French fries). A cross-sectional pre-posttest analysis of the campaign found that fruit intake significantly increased from baseline,⁶⁸ suggesting that a combination of marketing and environmental/policy-level changes may positively impact student dietary behaviours. Studies using randomized controlled designs and multiple campuses are needed to better characterize the effectiveness of this type of intervention.

Method of payment may also have an impact on student food choice. A study of college lunch payment methods explored the impact of using cash, a prepaid card or a prepaid card restricted to payment for healthier items only (e.g., turkey sandwich, salad and skim milk) on student purchases.⁶⁹ Students randomized to a restricted prepaid card consumed more calories from healthier items and fewer calories overall compared with the other payment methods. Restricted card users also consumed fewer calories from added sugars, total fat and saturated fat.⁶⁹ The controlled study environment, where student payment options were tightly managed, may not fully approximate the experience of free-living students, who often have access to multiple payment options. Further research is needed to understand whether these findings generalize to real-world campus dining settings where students have access to both a restricted card and other forms of payment (e.g., cash). However, this study provides preliminary evidence that use of restricted payment methods for meal purchases might help to promote healthier student meal choices. Such a strategy may be adaptable to à la cart dining venues, such as campus cafés and on-campus fast food restaurants.

Finally, trayless dining has been explored as a mechanism for influencing student food choice. A recent serial cross-sectional article analysing 3153 trays from a 5-day trayless dining intervention found that student food selection was influenced by the removal of trays.⁷⁰ In the trayless dining hall, there was a significant decrease in number of lunch servings, drink servings and dessert servings taken, as well as a decrease in food waste, compared with a control dining hall with trays.⁷⁰ Other studies of college/university dining have also reported decreased food waste when trays are removed.^{71, 72} This suggests that removal of dining trays could help attenuate the overconsumption seen in UA dining venues.²⁵ Further research is needed to replicate these findings in diverse settings over longer time periods. Such research would also benefit from collecting longitudinal data on individual-level student consumption and weight outcomes to better understand how trayless dining may affect students' dietary behaviour and health.

In addition to the potential for improved student health outcomes, trayless dining likely has positive implications for food service cost-savings, making it a strong candidate for garnering campus stakeholder support. One study of trayless college dining conducted focus groups with dining hall staff, who reported supporting the trayless initiative as a way to reduce food waste.⁷¹ However, concerns of staff members included increased dishware breakage and need for wiping down tables.⁷¹ It is important that potential unintended consequences such as these are understood when campuses look to make shifts in dining practices.

3.2.2 Residence-based interventions

One undergraduate health intervention, published in 2014, highlighted the potential use of college dormitory systems to promote health behaviours.⁷³ Sixty first-year students were assigned to live in either a Healthy Active Living (HAL) residence hall community or a control residence hall, based on preference. Students assigned to a HAL residence community had indicated moderate or strong preference for HAL housing, whereas students assigned to a control community had indicated either moderate preference or ambivalence towards HAL housing. During a 20-week period, the HAL residence hosted nutrition and PA-related seminars, activities and workshops with health professionals. In a pre-posttest analysis, intervention students reported greater moderate-to-vigorous PA as well as greater fruit and vegetable consumption at follow-up (adjusted for baseline) compared with control students.⁷³ This type of in-residence, community-based intervention may be a feasible model for many colleges with typical residential life systems, which utilize trained student staff to facilitate activities. This model may both be cost-effective (as students take the place of salaried staff) and have potential for broad impact.

Similarly, a 3-year study examining the impact of a peer health education programme reported that first-year students who engaged in ‘unhealthy weight management behaviours’ (e.g., eating according to a special diet and fasting to control weight) were more likely to have contact with peer health educators (PHEs).⁷⁴ However, by their second year, students that connected with PHEs in their first year had decreased their unhealthy weight management behaviours. This suggests that students with unhealthy weight-related behaviours were more likely to seek help from PHEs and that use of PHEs may be an effective strategy for promoting weight-related wellness among students.

A second study that utilized peer student leaders to promote healthy lifestyles on 8 college campuses reported that peer leaders had smaller declines in vegetable consumption over a 12-month period compared with control students.⁷⁵ In other words, all students reported declines in vegetable consumption, but peer leaders involved in the intervention had smaller declines than control students. The researchers hypothesized that the intervention may have attenuated the ‘typical’ decrease in vegetable consumption seen among students. However, due to the non-randomized recruitment strategy, these trends may also have been a function of systematic differences between active participants and control students (e.g., greater baseline interest in health).

In summary, campus-wide systems that utilize trained students as PHEs or other health/wellness-oriented leaders may be an impactful student health intervention, benefitting both the general student body as well as the leaders themselves. More intervention studies should leverage and evaluate student peer mentors as health promotion agents to benefit student diet, PA and weight. Additionally, future studies of this kind should make use of rigorous study designs to strengthen potential for causal inference.

3.2.3 Classroom-based interventions

In addition to promoting campus health in residential environments via student leaders, there is also potential for integrating active themes into classroom spaces. For example, availability of standing desks has been shown to benefit student health. A recent crossover design experiment revealed that, after 3 weeks of standing in class for a minimum of 5 h per week, all student participants (n = 21) had decreases in cardiometabolic risk factors (e.g., fasting blood lipids and glucose and resting blood pressure), and their metabolic equivalents of tasks (METs) significantly increased compared with their scores during 3 weeks of sitting.⁷⁶ Because students generally spend long periods of time in class, remodelling the classroom environment with standing desks, and encouraging their use, has the potential for broad impact. More research is needed to confirm these results in larger, diverse student populations over longer time periods. Studies are also needed to explore student receptivity to standing desk use.

Provision of standing desks is likely to be cost-prohibitive for many campuses. Classroom movement breaks might be a cost-effective alternative to standing desks. A mixed methods analysis of student perceptions during a one-semester course with regular activity breaks found that the majority of students appreciated the breaks and felt the breaks improved their focus and engagement.⁸⁰ However, there is currently no evidence to suggest that movement breaks have an impact on weight-related outcomes, and research on this topic is warranted.

Finally, PA course requirements show promise as a way to reach students who are least likely to be active on their own.^{36, 51} For example, ‘Project GRAD’, a university course designed to promote lifelong PA post-graduation, resulted in increased leisure-time PA, including strength and flexibility exercises, among female students immediately following the 15-week course. However, there was no effect on male students' PA levels. A 2-year follow-up of the project reported no significant effects on PA outcomes between the intervention and control groups, suggesting that more research is needed to understand and effectively leverage PA coursework to promote sustained outcomes.⁷⁷