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Research Brief

Examining the Weight Trajectory of College Students

Lizzy Pope, PhD, RD1; Danielle Hansen, BS2; Jean Harvey, PhD, RD1

1Departm 2 Bloomb Conflict o with thi Address ences, 25 Phone: ( �2016 S reserved http://dx

Journal

ABSTRACT

Objective: To examine the weight trajectory of students over 4 years of college. Methods: Anthropometric assessments were completed at the beginning and end of students’ freshman year and the end of senior year to calculate body mass index. Questionnaires assessing weight-related behaviors were completed in senior year. Results: Of the original 117 students, 86 remained in the study for 4 years. Body mass index was signif- icantly higher at the end of senior year (mean, 24.84; SD, 4.46) vs the beginning of freshman year (mean, 23.59; SD, 4.01; t[85] ¼ 5.61; P < .001). Weight was significantly higher at the end of senior year (mean, 71.32 kg; SD, 15.60) vs the beginning of freshman year (mean, 66.94 kg; SD, 14.02; t[85] ¼ 6.60; P < .001). Students’ mean weight gain was 4.38 kg and the sample increased from 23% to 41% overweight/obese. No significant associations were found between BMI and lifestyle factors. Conclusions and Implications: This study suggests that students gain weight throughout college, which highlights the need for weight control interventions to target more than just freshman college students. Key Words: BMI change, college students, obesity, weight gain (J Nutr Educ Behav. 2016;-:1-5.)

Accepted October 19, 2016.

INTRODUCTION

Young adults entering college are a spe- cific population of concern for over- weight and obesity because the transition from high school to college is a vulner- able time for weight gain.1 Weight gain in first-year college students is so prevalent it has been termed the fresh- man15. However, most studies debunk the myth that students gain 15 lb (6.8 kg) in their first year at college, and instead suggest that freshman weight gain is closer to 3–5 lb.2 There is no estab- lished correlation between weight gain or body mass index (BMI) and lifestyle factors for college students. Yet, it is acknowledged that college students generally do not meet physical activity recommendations or fruit and vege- table consumption guidelines.3 A trend has been observed of decreased fruit and

ent of Nutrition and Food Sciences, U erg School of Public Health, Johns Ho f Interest Disclosure: The authors’ confli s article on www.jneb.org. for correspondence: Lizzy Pope, PhD, R 4 Carrigan Wing, 109 Carrigan Dr, Un 802) 656-4262; Fax: (802) 656-0001; E- ociety for Nutrition Education and Beh . .doi.org/10.1016/j.jneb.2016.10.014

of Nutrition Education and Behav

vegetable intake paired with increased alcohol consumption when students enter college.4 A preliminary pattern of freshman weight gain continuing throughout college has been suggested, but more research is needed.5 Gropper et al6 conducted one of the only studies examining the changes in 131 students' weight and body composi- tion over 4 years of college. Significant gains in weight, percent body fat, and BMI were observed. Another study, by Racette et al,7 tracked changes in weight, BMI, exercise frequency, and dietary patterns of 204 students from fresh- man to senior year. Participants gained an average of 2.5 kg in 4 years and met neither physical activity recommen- dations nor dietary guidelines.

College weight gain is an important area to study because one's weight as a young adult is a predictor of the trajec-

niversity of Vermont, Burlington, VT pkins University, Baltimore, MD ct of interest disclosures can be found online

D, Department of Nutrition and Food Sci- iversity of Vermont, Burlington, VT 05405; mail: efpope@uvm.edu avior. Published by Elsevier, Inc. All rights

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tory of one's adult weight.8 Thus, tar- geting college students could be an effective way to combat the rising rates of overweight and obesity. This study aimed to examine the weight trajec- tory of college students over their 4 years in college and to determine whether there were significant associa- tions between obesity-related health behaviors and BMI in college seniors.

METHODS

Before beginning their first year at a northeastern public university in fall, 2011, incoming freshmen were re- cruited to participate in a 1-year study on physical activity, incentives, and height/weight change; this study was called Burn & Earn. Students were re- cruited via mailings to their homes dur- ing summer, 2011; 117 participants enrolled. Over the course of their fresh- man year, data on students' height and weight were collected 4 times: once at the beginning and once at the end of each semester. More information about this study and its results can be found elsewhere.9,10 The University of Vermont's Committee on Human Research in the Behavioral and Social Sciences approved the study protocol.

For the current study, participants from the 2011 Burn & Earn study were

1

Table. Mean Weight, Height, and Body Mass Index (BMI) Values for Participants at

Students experience continued weight gain over all 4 years of college.

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contacted again in spring, 2015, when they were seniors, and asked to partici- pate in an extension of the original study involving anthropometric assess- ments and information about their cur- rent health behaviors. Respondents scheduled a study assessment visit, when they completed a food frequency ques- tionnaire (FFQ), an alcohol use disor- ders identification test (AUDIT), and a general questionnaire. The general questionnaire was exploratory and as- sessed behaviors previously shown to be related to weight, including phys- ical activity frequency, living situation, grocery shopping habits, specific diet, relationship status, and work situa- tion.11,12 At the assessment visit, study personnel also measured students' height and weight. A digitally calibrated scale (model BW800S; Tanita, Arlington Heights, IL) was used to measure parti- cipants' weight; height (in centimeters) was assessed using a wall-mounted sta- diometer (Seca, Hanover, MD). Upon completion of the assessment visit, students were compensated $50 for participation. The FFQs were submit- ted to Nutrition Quest (Berkeley, CA) for analysis and the remainder of the data was compiled in the university laboratory. Changes in height, weight, and BMI were calculated by comparing 2011–2012 data with 2015 data.

The researchers used SPSS (version 23, IBM Corporation, Armonk, NY, 2015) to analyze the data. A paired- samplesttestwasperformedtoexamine anthropometricchangesbetweenfresh- man and senior years. An independent- samples t test was employed to examine differencesinweighttrajectorybetween originally overweight or obese students and originally normal weight students. The researchers performed regression analyses to determine associations be- tween health behaviors and changes in BMI/weight.

the Beginning and End of Freshman Year and End of Senior Year (n ¼ 86)

Weight, kg Height, cm BMI, kg/m2

Beginning of freshman year (fall, 2011)

66.94 (14.02) 168.23 (8.88) 23.54 (4.00)

End of freshman year (spring, 2012)

68.26 (13.74) 168.51 (9.00) 23.98 (3.93)

End of senior year (spring, 2015)

71.32 (15.60)a,b 169.13 (8.95)a,b 24.84 (4.46)a,b

aSignificantly different from beginning of freshman year to end of senior year (P < .001, paired-samples t test); bSignificantly different from end of freshman year to end of senior year (P < .001, paired-samples t test). Note: Data are shown as mean (SD).

RESULTS

Of the original 117 participants, 86 re- turned to the laboratory for follow-up measurements; this represented a 73.5% retention rate. Analyses of weight, BMI, and height change were performed using only the 86 partici- pants who had complete data. Box plots of weight and BMI change indicated several outliers; however, there was no scientific justification for treating out-

liers differently. Histograms and q–q plots of weight change, BMI change, and the residuals of weight and BMI change indicated that the assumption of normality needed for valid t tests could be accepted. No significant differ- ence was observed in BMI at the begin- ning of freshman year between those who participated in the senior year study and those who did not participate (F1,115 ¼ 0.14, P ¼ .69). Of the 86 stu- dents who completed the study, 58 were women and 28 were men. Average age was 21.5 years. Ninety-three percent of participants were white and 7% were Asian. Four students reported being His- panic or Latino. As seen in the Table, there were significant increases in mean BMI, weight, and height from the beginning of freshman year to the end of senior year, as well as from the end of freshman year to the end of se- nior year. Mean weight gain was 4.38 kg over 4 years, 2.94 kg of which occurred after freshman year. Mean height increase from the beginning of freshman year to the end of senior year was 0.9 cm, when men gained 1 cm on average and women grew by0.85cm.

The number of overweight (BMI ¼ 25–29.9) and obese (BMI $30) students increased from 20 at the beginning of freshmanyearto35bytheendofsenior year. At the conclusion of senior year, 41% of the sample was overweight or

obese (Figure). Only 11.6% of students maintained weight within 1 kg of fresh- man year weight. A total of 21% of stu- dents maintained weight within 3% of freshman year weight over 4 years. Ste- vens et al13 proposed a 3% weight change as the definition of weight maintenance. Twenty-two students, or 26% of the sample, maintained BMI within �3% of their freshman year BMI. There was no significant differ- ence in total change in BMI over 4 years between those who entered their fresh- man year in the normal BMI range (n ¼ 66) and those who entered with a BMI in the overweight/obese categories (n ¼ 20) (P ¼ .93).

Based on the results of the FFQ, stu- dents' average caloric intake was 1,889 kcal/d. Mean fruit and vegetable consumption was 1.06 and 1.46 cups/d, respectively. Students consumed an average of 203 kcal/d of alcohol. Women averaged 164 kcal of alcohol, whereas men averaged 284 kcal of alcohol. The AUDIT results showed that 62% of the sample consumed alcohol 2–3 times/wk, and the most frequent response for number of drinks when drinking was 3–4 drinks. The AUDIT scores also indicated that 96.5% of participants were at very low risk for problem drinking behavior. Regression analyses indi- cated that there were no significant as- sociations between weight change or BMI and lifestyle factors, including how students commuted to campus, relationship status, or where they ob- tained their food. Only 15% of partici- pants regularly met physical activity guidelines of achieving 30 minutes of moderate physical activity 5 times/wk.

Overweight/Obese Fall 2011

Overweight/Obese Spring 2015

Healthy Weight Fall 2011

Healthy Weight Spring 2015

= Overweight/Obese to Healthy Weight

= Healthy Weight to Overweight/Obese

= Stayed Overweight/Obese

*49 students remained in the healthy weight BMI category throughout the study and are not depicted in the figure.

Figure. Movement between body mass index categories for participants who started freshman year in the overweight/obese category (fall, 2011) and for those who ended senior year in the overweight/obese category (spring, 2015).

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DISCUSSION

These results suggest that a significant increase occurs in weight and BMI over the 4 years students spend at col- lege. However, the origin of this weight gain remains unclear. Although there was a statistically significant increase in height over 4 years, it was #1 cm for both men and women, which was not clinically significant in that it did not plausibly account for the entire 4.38-kg weight gain observed. Further-

more, the significant increase in BMI indicated that height increase did not entirelyaccountforthemeasuredweight increase. Because the researchers as- sessed height using a stadiometer, measurement error also could have contributed to the small height in- crease observed.

The average reported daily caloric intake remained lower than the needs of most college students regardless of gender.Thiscaloricdeficitdidnotmatch the observed weight gain. Although the

accuracy of self-report data is disputed, studies showed that the validity and reli- abilityofFFQdataspecificallyaremoder- ate to high on a population level.14

However, previous studies on dietary recall found that those who are over- weight or obese are more likely to under- report intake than are those of a healthy weight. These studies also indicated that individuals aged 19–29 years and women are likely to underreport.15 Par- ticipants in this study fell into several of thesubgroupsmostlikelytounderreport intake. Furthermore, an understanding of portion sizes is necessary for accurate FFQ reporting. It is possible that despite providing examples of various portion sizes for participants, they still might have underreported portion sizes, which might have resulted in the lower average calorie intakes recorded.

TheFFQdatashowedthatmeanfruit and vegetable consumption was below the recommended intake for young adults.16 It is likely that energy-dense foods displaced fruits and vegetables, leading to this deficiency. Although the alcohol intake reported by this sam- ple was generally not problematic, and in fact fell within the 2015 Dietary GuidelinesforAmericans,whichrecom- mend a maximum of 1 drink/d for women and 2 drinks/d for men, the majority of students reported drinking on only 2–3 d/wk. This suggests that alcohol calorie intake exceeded the guidelines on the days when alcohol was consumed. Average reported calo- ries from alcohol were >10% of the to- tal average reported daily calories. No associations were found between alcohol consumption and weight change, but alcohol contributed a meaningful num- ber of calories to participants' diets.

Physical activity habits were another lifestyle factor hypothesized to be associated with weight or BMI change. The American Heart Association rec- ommends at least 30 minutes of moderate-intensity aerobic activity 5 d/wk.17 Only 15% of participants regularly met these physical activity guidelines, but the researchers found noassociationsbetweenchangeinweight or BMI and meeting physical activity guidelines. However, it is possible that physical activity decreased from fresh- man to senior year, which may have contributed to the observed weight gain and BMI increase.

Although there were no associations between weight change and lifestyle

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behaviors, the increase in the preva- lence of overweight and obesity from the beginning of freshman year to the endofsenioryearwassignificant.These results were similar to findings of one of the only other studies examining weight change in college students over 4years:Gropperetal6 foundanincrease in overweight or obesity from 18% to 31%. That study also found an average weight gain of 3.0 kg in 4 years and an average increase in BMI of 1.0 kg/m2

over4 years. In comparison, thecurrent study found an average increase of 4.38 kg in weight and 1.3 kg/m2 in BMI. Both studies found significant in- creases in weight and BMI, but the cur- rent study found larger increases in both weight and BMI, as well as a greater increase in the prevalence of overweight and obesity. The significant increase in overweight and obesity is especially surprising given the recruit- ing method for the study. Participants originally signed up for a study on incentivizing physical activity. Theo- retically, this should have been a moti- vated population that was more inclined to physical activity than a random sam- ple. Furthermore, all participants were enrolled at a reputable 4-year univer- sity and the sample was predominantly white. Both lower education and mi- nority race are factors associated with obesity.18,19 These results suggest that even in populations considered to be at lower risk for obesity, small and consistent weight gains become significant over time.

Need for health behavior– related interventions throughout students’ 4 years at college rather than only in the freshman year.

The significant increases seen in BMI, weight, and the proportion of stu- dents in the overweight/obese BMI cat- egories are concerning given the health risks associated with overweight/obesity in adolescence and young adulthood, as well as research indicating that BMI as a young adult is correlated with BMI later in life.20,21 Obese young adults are more likely to experience hypertension,

diabetes, polycystic ovarian syndrome, and psychosocial distress, all of which can be debilitating.22 These health consequences may also track into adulthood, because research by The et al21 indicated that the risk of becoming severely obese by age 30 years was much greater for obese adolescents than for overweight or normal weight adolescents. Perhaps most concern- ing, Zimmermann et al23 found that the risk of mortality in adulthood was twice as great for obese young adults compared with normal weight young adults. The results of the current study combined with previous research on the negative outcomes of obesity in young adulthood suggest that more in- terventions are needed to help young adults maintain a healthy weight.

Strengths of the study include the longitudinal weight and BMI data, which span over 4 years. Researchers measured height and weight for partic- ipants in the laboratory rather than use self-reported height/weight data. This study had a sample size (86 partici- pants) representing a 73.5% retention rate from the original study. Another strength was the magnitude of data collected from FFQs, AUDIT scores, and a lifestyle questionnaire.

Although the plethora of data was a strength of the study, except for weight and height, the majority of data are self-reported. Furthermore, the ques- tionnaire asking about general weight- relatedbehaviorssuchaslivingsituation andrelationshipstatuswasnotavalidated questionnaire, but rather an explor- atory questionnaire meant to inform future research. Another limitation of this study was the absence of a control group to represent the weight trajec- tory of those who did not attend col- lege. The sample lacked diversity but was representative of the New England state where the study was conducted. A final limitation was the gap in data between participants' freshman and senior years. It is unknown whether weight gain was consistent over these 4 years or whether a majority of the weight gain occurred at a certain time after freshman year. Based on the average weight change in freshman year and average weight change over all 4 years, it can be concluded that weight gain did not continue at the same rate of 1.44 kg/y. A study by Lloyd-Richardson

et al5 suggested that weight gain con- tinues over students' sophomore year, but at a slower rate. More research is needed to determine the rate at which weight gain occurs over sophomore, junior, and senior years.

IMPLICATIONS FOR RESEARCH AND PRACTICE

Future research with more frequent measurements over 4 years at college is necessary to expand on the current results. More objective measures of eating and physical activity would also strengthen future studies. Pairing a 4-year university with a 2-year com- munity college or a sample of young adults not pursuing further education after high school would also provide valuable controls in future research. A more diverse sample would increase the ability of future studies to be applied to populations outside New England. In addition, more detailed body measurements could be used to differentiate muscle gain from fat gain.

The study's results, which suggest continued weight gain over all 4 years of college, are important for health practitioners targeting a college popu- lation. This study highlights the need for health behavior–related interven- tions throughout students' 4 years at college rather than only in the fresh- man year. The significant increase in BMI observed from freshman to se- nior year translated into a dramatic increase in the prevalence of over- weight/obesity in the sample from 23% to 41% over 4 years. The mean weight gain of 4.38 kg was not ex- plained by measured lifestyle behav- iors including alcohol consumption or meeting diet and physical activity guide- lines.

ACKNOWLEDGMENTS

This study was supported by a US Department of Agriculture HATCH Grant (Dr Pope, Principal Investigator). The authors thank Lucy Mower for help with data collection, and Alan Ho- ward for assistance with the statistical analysis.

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CONFLICT OF INTEREST

The authors have not stated any con- flicts of interest.