Abstract
Introduction: Physical activity and a healthy diet have been recommended to help reverse the increasing prevalence of overweight among adolescents and adults in the United States.
Methods: Data is from the 1995 National College Health Risk Behavior Survey. A representative sample of US undergraduate college students (n = 4609) were analyzed to examine associations of physical activity and food choice with weight management goals and practices.
Results: Based on self-reported height and weight, 35% of students were overweight or obese (body mass index ≥ 25.0). Nearly half (46%) of all students reported they were trying to lose weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Among female and male students, using logistic regression to control for demographics, trying to lose weight was associated with participation in vigorous physical activity and strengthening exercises, and consumption of ≤ 2 servings/day of high-fat foods. Female and male students who reported using exercise to lose weight or to keep from gaining weight were more likely than those who did not to participate in vigorous, strengthening, and moderate physical activity, and were more likely to eat ≥ 5 servings/day of fruits and vegetables and ≤ 2 servings/day of high-fat foods. Among students who were trying to lose weight, only 54% of females and 41% of males used both exercise and diet for weight control.
Conclusion:
Colleges should implement programs to increase student awareness of healthy weight management methods and the importance of physical activity combined with a healthy diet.
Keywords
Introduction
Overweight and obese adults are at increased risk for mortality and morbidity related to a wide range of chronic diseases, including coronary heart disease, hypertension, dyslipidemia, diabetes mellitus, gallbladder disease, and some types of cancer.
1
, 2
Recent estimates of body mass index (BMI) indicate that more than half (54%) of adults, 12% of adolescents, and 14% of children in the United States are overweight.3
, National Institutes of Health, National Heart, Lung, and Blood Institute
Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. US Dept of Health and Human Services, Public Health Service, National Institutes of Health, National Heart, Lung, and Blood Institute,
Washington, DC1998
4
Further, the prevalence of overweight in each of these age groups has increased significantly over the past 15 years.3
, National Institutes of Health, National Heart, Lung, and Blood Institute
Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. US Dept of Health and Human Services, Public Health Service, National Institutes of Health, National Heart, Lung, and Blood Institute,
Washington, DC1998
4
, 5
, 6
Recommendations for the long-term treatment and prevention of obesity in adults include multicomponent interventions that combine a healthy diet and exercise with behavior modifications designed to facilitate maintenance of these lifestyle changes throughout the life span.
3
, National Institutes of Health, National Heart, Lung, and Blood Institute
Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. US Dept of Health and Human Services, Public Health Service, National Institutes of Health, National Heart, Lung, and Blood Institute,
Washington, DC1998
7
National objectives for healthy dietary behaviors and physical activity include increased consumption of fruits and vegetables, reduced consumption of dietary fat, accumulation of at least 30 minutes of moderate physical activity most days of the week, participation in vigorous physical activity that promotes the development of cardiorespiratory fitness for 20 or more minutes at least 3 days per week, and regular performance of physical activities that enhance and maintain muscular strength, muscular endurance, and flexibility.2
, 8
, 9
, 10
US Dept of Health and Human Services, Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives—full report, with commentary. Washington, DC: US Dept of Health and Human Services, Public Health Service, 1991. US Dept of Health and Human Services pub no PHS 91–50212.
A national telephone survey of adults who were trying to lose weight found that 71% of women and 62% of men reported both changing their diets and exercising more.
11
Use of low-fat and low-calorie foods was widespread among both women and men. The types of exercise most commonly employed included walking and aerobics classes among women, and walking and weight training among men. Women were more likely than men to engage in potentially harmful and unhealthy (e.g., diet pills, vomiting, and laxatives) weight control practices. A study of high school students participating in the Youth Risk Behavior Survey found that females who were trying to lose weight limited their intake of high-fat meats, fried foods, and dessert foods; males limited their intake of high-fat dessert foods.12
Consumption of fruits and vegetables was not associated with trying to lose weight among female or male students. Vigorous physical activity and muscle strengthening exercise were associated with trying to lose weight among female students, and trying to gain weight among male students.Colleges and universities are potentially important settings for reducing the prevalence of overweight in the adult population through the promotion of healthy weight management practices. More than 12 million students currently are enrolled in the nation’s 3600 colleges and universities.
13
One in 4 persons aged 18 to 24 years in the United States currently is either a full- or part-time college student,13
, 14
and half of all persons aged 20 to 24 years have attended college.15
While overweight and obesity appear to track from childhood into adulthood, overweight during late adolescence is most strongly associated with increased risk of overweight in adulthood.16
Colleges and universities provide numerous opportunities to positively influence physical activity, nutrition, and weight management behaviors of large numbers of older adolescents and young adults in an educational setting.Although numerous intervention studies have documented the extent to which subjects adhere to prescribed dietary and physical activity regimens during weight loss programs, few population-based observational studies have examined the extent to which persons who are trying to control their weight include fruits and vegetables and limit high-fat foods in their diets, and the extent to which they engage in specific types of physical activity. The 1995 National College Health Risk Behavior Survey (NCHRBS), part of the Youth Risk Behavior Surveillance System (YRBSS) implemented by the Centers for Disease Control and Prevention (CDC), assessed a broad range of priority health risk behaviors among a nationally representative sample of undergraduate college students attending 2- and 4-year institutions.
17
We analyzed data from the 1995 NCHRBS to examine associations of physical activity and food choice with weight management goals and practices. Our study extends the current literature by describing the demographic distribution of overweight and selected weight management goals and practices among US college students, and the types of physical activity and food choices associated with these weight management goals and practices.Methods
Study design
The 1995 NCHRBS, a national mail survey of college students, used a 2-stage cluster sample design to produce a representative sample of undergraduate college students aged ≥ 18 years in the United States. The first-stage sampling frame contained 2919 primary sampling units, consisting of 2- and 4-year colleges and universities. Technical and trade schools or noncollegiate training programs (e.g., truck driving schools, security guard training, and beautician schools) were excluded from the sampling frame. From this list of colleges and universities, 74 2-year and 74 4-year institutions were selected from 16 strata formed on the basis of the relative percentage of black and Hispanic students in the institutions. The colleges and universities were selected with probability proportional to undergraduate enrollment size. Overall, 136 (92%) of the 148 selected institutions participated in the survey.
The second sampling stage consisted of a simple random sample drawn from a list of the full- and part-time undergraduate students aged ≥ 18 years enrolled in the 136 participating colleges and universities. Differential sampling rates were used to ensure sufficient numbers of black and Hispanic students in the sample. After allowing for assumed student nonresponse and ineligibility rates, 56 students were targeted in each 4-year institution and 72 students were targeted in each 2-year institution. Sampled students received a 96-item self-administered questionnaire via mail. Follow-up mailings and telephone calls were made as needed to increase student participation rates. Responses to the questionnaire were both voluntary and confidential. Data collection was initiated in January 1995 and completed by July 1995. A weighting factor was applied to each student record to adjust for the varying probabilities of selection at each stage of sampling, school- and student-level nonresponse, and oversampling of black and Hispanic students. Of the 7442 sampled students determined to be eligible for the study, 4838 (65%) completed the questionnaire. Additional details of the 1995 NCHRBS methodology are available elsewhere.
17
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Among the 4838 respondents who completed questionnaires, 229 identified themselves as graduate students, even though they were included in the list of undergraduate students provided by the university. These 229 records were not included in these analyses.Data analyses
Participation in vigorous physical activity, muscle strengthening and toning exercise, and moderate physical activity were assessed using the following 3 questions: (1) “On how many of the past 7 days did you exercise or participate in sports activities for at least 20 minutes that made you sweat and breathe hard, such as basketball, jogging, swimming laps, tennis, fast bicycling, or similar aerobic activities?”; (2) “On how many of the past 7 days did you do exercises to strengthen or tone your muscles, such as push-ups, sit-ups, or weight lifting?”; and (3) “On how many of the past 7 days did you walk or bicycle for at least 30 minutes at a time? (Include walking or bicycling to or from class or work.).” Consumption of fruits and vegetables was measured by 4 separate questions, and consumption of high-fat foods was measured by 3 separate questions, all of the form: “Yesterday, how many times did you…[eat fruit; drink fruit juice; eat green salad; eat cooked vegetables; eat hamburger, hot dogs, or sausage; eat French fries or potato chips; eat cookies, doughnuts, pie, or cake]?” Responses for each food choice question included: 0 times, 1 time, 2 times, 3 or more times. Therefore, daily servings of fruits and vegetables could range from 0 to 12; daily servings of high-fat foods could range from 0 to 9. Weight management practices were assessed by 4 separate questions, all of the form: “During the past 30 days, did you…[exercise, diet, take diet pills, vomit or take laxatives] to lose weight or keep from gaining weight?” Students also were asked about their perception of their body weight (responses: very underweight, slightly underweight, about the right weight, slightly overweight, very overweight); their current weight management goals (responses: lose weight, gain weight, stay the same weight, I am not trying to do anything about my weight); their current height and weight; and whether they had ever received information from their college or university on various health topics, including “physical activity and fitness” and “dietary behaviors and nutrition.”
Self-reported height and weight were used to calculate BMI, kg/m2, a measure of weight adjusted for stature. According to guidelines recently published by the National Institutes of Health, overweight in adults is defined as 25.0 ≤ BMI < 30.0 and obesity as BMI ≥ 30.0.
3
Unless otherwise specified, the term overweight in our study refers to students with BMI ≥ 25.0 (the point above which mortality and morbidity rates begin to rise) and includes obese students.National Institutes of Health, National Heart, Lung, and Blood Institute
Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. US Dept of Health and Human Services, Public Health Service, National Institutes of Health, National Heart, Lung, and Blood Institute,
Washington, DC1998
Since frequencies for participation in physical activity, consumption of fruits and vegetables, and consumption of high-fat foods were not normally distributed, these behaviors were analyzed as dichotomous variables. Cut-points were chosen in a manner consistent with national health objectives and recommendations for physical activity and healthy diet: 20 minutes of vigorous physical activity ≥ 3 days/week; muscle strengthening exercise ≥ 3 days/week; 30 minutes of moderate physical activity ≥ 5 days/week; ≥ 5 servings/day of fruits and vegetables; and ≤ 2 servings/day of high-fat foods.
2
, 8
, 9
, 10
, US Dept of Health and Human Services, Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives—full report, with commentary. Washington, DC: US Dept of Health and Human Services, Public Health Service, 1991. US Dept of Health and Human Services pub no PHS 91–50212.
19
The American Cancer Society has recommended decreasing the proportion of high school students who eat > 2 servings/day of high-fat foods.19
Prevalence estimates and adjusted odds ratios (OR) from logistic regression models were used to describe the independent effects of demographic factors (i.e., gender, age, race/ethnicity, employment status, and type of institution [2-year vs 4-year] attended) on the distribution of overweight and on weight management goals and practices. To avoid problems with collinearity, marital status was not included in logistic regression models (marital status was strongly correlated with age, r = 0.7). Full- or part-time student status was dropped from final models because it was not associated with overweight or weight management goals and practices. In subsequent analyses, separate logistic regression models for female and male students were used to determine the types of physical activity and food choice behaviors associated with specific weight management goals and practices, controlling for demographics.
All prevalence estimates, adjusted odds ratios, and corresponding 95% confidence intervals (CIs) were calculated using weighted data and SUDAAN, statistical analysis software that accounts for the complex sample design.
20
Differences between prevalence estimates were considered statistically significant if 95% CIs did not overlap, and adjusted odds ratios were considered statistically significant if 95% CIs did not include 1.0.Results
The school-level response rate was 92% and the student-level response rate was 65%, representing an overall response rate of 60%. Based on weighted prevalence estimates, nearly half (45.6%; 95% CI, ± 3.9%) of all undergraduate students attended 2-year colleges. Compared to students attending 4-year colleges, students attending 2-year colleges were more often aged 25 years or older (51.3% vs 24.1%), of Hispanic ethnicity (9.5% vs 5.1%), employed full time (34.9% vs 13.4%), attending college part time (48.6% vs 17.8%), and married (30.2% vs 15.1%) (Table 1).
Table 1Demographic characteristics of undergraduate college students, by type of institution attended—United States, 1995
| Category | Total population (n = 4609) | 2-year college (n = 2435) | 4-year college (n = 2174) | |||
|---|---|---|---|---|---|---|
| % | (95% CI) | % | (95% CI) | % | (95% CI) | |
| Gender | ||||||
| Female | 55.5 | (53.4–57.7) | 58.1 | (55.4–60.7) | 53.5 | (50.1–56.8) |
| Male | 44.5 | (42.3–46.6) | 41.9 | (39.3–44.6) | 46.5 | (43.2–49.9) |
| Age, years | ||||||
| ≥40 | 9.8 | (8.2–11.3) | 15.4 | (13.2–17.7) | 5.1 | (3.0–7.1) |
| 25–39 | 26.6 | (24.4–28.9) | 35.9 | (33.3–38.4) | 19.0 | (15.4–22.6) |
| 18–24 | 63.6 | (60.4–66.8) | 48.7 | (45.5–52.0) | 75.9 | (70.6–81.3) |
| Race ethnicity | ||||||
| Black | 10.3 | (8.5–12.0) | 10.5 | (7.3–13.8) | 10.0 | (8.4–11.7) |
| Hispanic | 7.1 | (5.8–8.5) | 9.5 | (7.1–11.9) | 5.1 | (3.8–6.5) |
| Asian/Pacific Islander | 6.1 | (4.3–7.8) | 6.3 | (3.2–7.4) | 6.7 | (4.0–9.3) |
| Other | 3.8 | (3.1–4.5) | 4.5 | (3.5–5.6) | 3.2 | (2.3–4.1) |
| White | 72.8 | (69.3–76.2) | 70.1 | (64.7–75.5) | 75.0 | (70.5–79.4) |
| Employment, hours/week | ||||||
| ≥40 | 23.2 | (20.8–25.6) | 34.9 | (31.4–38.4) | 13.4 | (10.3–16.4) |
| 1–39 | 49.5 | (47.5–51.6) | 43.7 | (40.8–46.7) | 54.4 | (51.6–57.1) |
| 0 | 27.3 | (25.1–29.5) | 21.3 | (18.4–24.2) | 32.3 | (29.1–35.4) |
| Student Status | ||||||
| Part time | 31.8 | (28.7–34.9) | 48.6 | (45.1–52.0) | 17.8 | (13.0–22.6) |
| Full time | 68.2 | (65.1–71.3) | 51.4 | (48.0–54.9) | 82.2 | (77.4–87.0) |
| Marital Status | ||||||
| Married | 21.9 | (19.5–24.3) | 30.2 | (27.7–32.7) | 15.1 | (11.0–19.1) |
| Separated/divorced/widowed | 8.6 | (7.5–9.7) | 12.4 | (10.9–13.9) | 5.5 | (3.9–7.1) |
| Never married | 69.4 | (66.4–72.4) | 57.4 | (54.5–60.3) | 79.4 | (74.3–84.5) |
legend CI, confidence interval.
Among all undergraduate college students, 37.6% participated in vigorous physical activity ≥ 3 days/week (Table 2). Fewer students participated in muscle strengthening exercises ≥ 3 days/week (29.9%), or 30 minutes of moderate physical activity such as walking or bicycling ≥ 5 days/week (19.5%). One of 4 (26.3%) students ate ≥ 5 servings/day of fruits and vegetables, and 3 of 4 students (78.0%) ate ≤ 2 servings/day of high-fat foods. Female students were less likely than male students to participate in vigorous physical activity and muscle strengthening exercises, but were more likely to eat ≤ 2 servings/day of high-fat foods.
Table 2Physical activity, food choice, body weight, and weight management goals and practices among undergraduate college students, by gender—United States, 1995
| Category | Total popoulation (n = 4609) | Female (n = 2823) | Male (n = 1742) | |||
|---|---|---|---|---|---|---|
| % | (95% CI) | % | (95% CI) | % | (95% CI) | |
| Physical activity | ||||||
| Vigorous | 37.6 | (35.5–39.7) | 33.0 | (30.7–35.5) | 43.7 | (40.5–46.9) |
| Strengthening | 29.9 | (28.2–31.6) | 26.8 | (24.9–28.6) | 33.9 | (31.1–36.7) |
| Moderate | 19.5 | (17.9–21.1) | 19.3 | (17.4–21.2) | 19.7 | (17.4–22.0) |
| Food choice | ||||||
| ≥5 fruits & vegetables | 26.3 | (24.4–28.2) | 25.0 | (23.0–27.0) | 28.1 | (25.3–30.9) |
| ≤2 High-fat foods | 78.0 | (76.3–79.6) | 84.8 | (83.1–86.4) | 69.4 | (66.9–72.0) |
| Body weight, BMI | ||||||
| Obese (BMI ≥ 30.0) | 11.4 | (10.3–12.5) | 12.0 | (10.6–13.4) | 10.7 | (9.1–12.3) |
| Overweight (25.0 ≤ BMI < 30.0) | 23.6 | (22.2–25.0) | 17.9 | (16.4–19.4) | 30.6 | (28.1–33.1) |
| Normal weight (18.5 ≤ BMI < 25.0) | 59.9 | (58.1–61.7) | 63.5 | (61.5–65.5) | 55.4 | (52.4–58.3) |
| Underweight (BMI < 18.5) | 5.1 | (4.5–5.7) | 6.6 | (5.6–7.6) | 3.3 | (2.4–4.3) |
| Body weight, self-perception | ||||||
| Overweight (very) | 6.4 | (5.7–7.1) | 8.8 | (7.6–9.9) | 3.4 | (2.5–4.4) |
| Overweight (slightly) | 35.2 | (33.5–36.8) | 40.1 | (38.1–42.0) | 29.0 | (26.5–31.5) |
| About the right weight | 46.2 | (44.6–47.8) | 42.2 | (40.1–44.3) | 51.1 | (48.7–53.5) |
| Underweight (slightly or very) | 12.2 | (11.2–13.3) | 9.0 | (7.8–10.1) | 16.4 | (14.5–18.4) |
| Weight management goals | ||||||
| Lose weight | 46.4 | (44.6–48.2) | 59.8 | (57.7–61.8) | 29.6 | (27.1–32.1) |
| Stay same weight | 20.1 | (18.7–21.4) | 18.3 | (16.8–19.9) | 22.1 | (20.1–24.2) |
| Gain weight | 10.3 | (9.3–11.3) | 2.9 | (2.2–3.6) | 19.7 | (17.8–21.6) |
| Do nothing about weight | 23.2 | (21.7–24.7) | 19.0 | (17.3–20.7) | 28.6 | (26.1–31.1) |
| Weight management practices | ||||||
| Exercise | 53.6 | (51.7–55.5) | 62.6 | (60.3–65.0) | 42.3 | (39.5–45.0) |
| Diet | 30.8 | (29.1–32.5) | 42.1 | (39.7–44.4) | 16.7 | (14.8–18.7) |
| Diet pills | 4.3 | (3.7–5.0) | 7.0 | (5.8–8.2) | 1.1 | (0.6–1.6) |
| Vomiting or laxatives | 2.5 | (2.0–3.1) | 4.2 | (3.2–5.1) | 0.6 | (0.1–1.0) |
legend CI, confidence interval; BMI, body mass index.
a Exercised or took part in sports that made them sweat and breathe hard for at least 20 minutes on ≥3 of the past 7 days.
b Did muscle strengthening or toning exercises, such as push-ups, sit-ups, or weight lifing on ≥3 of the past 7 days.
c Walked or bicycled, including to or from class or work, for at least 30 minutes at a time on ≥5 of the past 7 days.
d Ate ≥5 servings of fruit, fruit juice, green salad, or cooked vegetables yesterday.
e Ate ≤2 servings of hamburger, hot dogs, sausage, french fries, potato chips, cookies, doughnuts, pie, or cake yesterday.
f Based on self-reported height and weight, body mass index (BMI = weight [kg]/height [m]2) was used to define weight categories using guidelines proposed by the National Institutes of Health for adults aged 18 years and older.
g Response to question, “How do you describe your weight?”
h Response to question, “Which of the following are you trying to do about your weight?”
i To lose weight or keep from gaining weight, during the past 30 days.
Although 35.0% of students were overweight or obese based on BMI, 41.6% considered themselves to be slightly or very overweight, and 46.4% reported they were trying to lose weight at the time of the survey (Table 2). More than half (53.6%) of all students reported using exercise and 30.8% of students reported using diet to control their weight (i.e., to lose weight or keep from gaining weight) during the 30 days preceding the survey. Diet pills (4.3%) and vomiting or laxatives (2.5%) were less common methods of weight control. Although females were less likely than males to be overweight, they were more likely than males to perceive themselves to be slightly or very overweight; to be trying to lose weight; and to use exercise, diet, diet pills, and vomiting or laxatives for weight control.
Physical activity, food choice behaviors, and weight management goals did not vary by type of institution attended. However, students attending 2-year colleges were more likely than students attending 4-year colleges to be overweight or obese (39.9% ± 2.4% vs 30.9% ± 2.6%), to perceive themselves to be slightly or very overweight (46.1% ± 2.6% vs 37.7% ± 2.3%), and to use diet (34.3% ± 2.9% vs 27.9% ± 2.1%) and diet pills (5.9% ± 1.2% vs 3.1% ± 0.7%) for weight control.
Logistic regression models were used to examine the independent effects of demographic factors on being overweight, trying to lose weight, and using specific weight control methods (Table 3). Demographic factors associated with overweight included being older, black, and employed full time. Female and Asian and Pacific Islander (API) students were least likely to be overweight. Trying to lose weight was associated with being female and older. Black students and API students were less likely than white students to be trying to lose weight. Female students were more likely than male students to report using exercise to lose weight or to keep from gaining weight. The association between race/ethnicity and use of exercise for weight control varied by gender. Among females, black (OR = 0.54; 95% CI, 0.41–0.70), Hispanic (OR = 0.73; 0.58–0.93), and API (OR = 0.43; 0.29–0.65) students were less likely than white students to use exercise for weight control. Among males, only API (OR = 0.59, 0.39– 0.91) students were less likely than white students to use exercise for weight control. Use of diet for weight control was associated with being female, older, and attending a 2-year college. Use of diet pills for weight control was associated with being female, employed full time, and attending a 2-year college. Black students were less likely than white students to use diet pills for weight control. Use of vomiting or laxatives for weight control was associated with being female, younger, and employed full time. Greater use of these weight control methods among female students was not solely the result of a greater proportion of females than males attempting to control their weight. Even among students who reported they were trying to lose weight or stay the same weight, all 4 weight control methods were significantly more common among female than male students (data not shown).
Table 3Prevalence and adjusted OR for being overweight, trying to lose weight, and using selected weight management practices among undergraduate college students, by demographic characteristics—United States, 1995
| Category | Weight Management Practices | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overweight (n = 4359) | Trying to lose weight (n = 4408) | Exercise (n = 4401) | Diet (n = 4407) | Diet pills (n = 4413) | Vomiting or laxatives (n = 4404) | |||||||||||||
| % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | |
| Gender | ||||||||||||||||||
| Female | 29.9 | 0.51 | (0.44–0.60) | 59.8 | 3.51 | (3.03–4.06) | 62.6 | 2.35 | (2.02–2.74) | 42.1 | 3.64 | (3.09–42.9) | 7.0 | 7.00 | (4.18–11.71) | 4.2 | 8.07 | (3.24–20.09) |
| Male | 41.3 | 1.00 | (referent) | 29.6 | 1.00 | (referent) | 42.3 | 1.00 | (referent) | 16.7 | 1.00 | (referent) | 1.1 | 1.00 | (referent) | 0.6 | 1.00 | (referent) |
| Age, years | ||||||||||||||||||
| ≥40 | 56.3 | 3.58 | (2.75–4.65) | 59.0 | 1.42 | (1.12–1.81) | 58.9 | 1.06 | (0.81–1.39) | 41.4 | 1.36 | (1.06–1.74) | 5.2 | 0.80 | (0.45–1.41) | 0.5 | 0.10 | (0.02–0.44) |
| 25–39 | 44.4 | 2.10 | (1.71–2.56) | 49.3 | 1.10 | (0.93–1.32) | 52.2 | 0.90 | (0.76–1.08) | 34.3 | 1.19 | (0.99–1.43) | 5.7 | 1.09 | (0.75–1.60) | 2.7 | 0.66 | (0.39–1.13) |
| 18–24 | 27.4 | 1.00 | (referent) | 43.3 | 1.00 | (referent) | 53.4 | 1.00 | (referent) | 27.8 | 1.00 | (referent) | 3.7 | 1.00 | (referent) | 2.8 | 1.00 | (referent) |
| Race ethnicity | ||||||||||||||||||
| African-American | 48.7 | 2.03 | (1.62–2.55) | 43.4 | 0.78 | (0.62–0.97) | 48.5 | 0.73 | (0.57–0.93) | 28.3 | 0.80 | {0.62–1.03) | 3.4 | 0.65 | (0.42–0.99) | 2.0 | 0.68 | (0.30–1.57) |
| Hispanic | 33.9 | 0.96 | (0.77–1.20) | 46.6 | 0.93 | (0.76–1.14) | 53.7 | 0.96 | (0.78–1.18) | 30.5 | 0.91 | (0.72–1.16) | 4.3 | 0.80 | (0.54–1.20) | 3.7 | 1.33 | (0.76–2.31) |
| Asian/Pacific Islander | 15.3 | 0.39 | (0.26–0.58) | 34.4 | 0.67 | (0.50–0.91) | 37.3 | 0.51 | (0.37–0.69) | 23.1 | 0.79 | (0.56–1.10) | 2.4 | 0.61 | (0.29–1.29) | 1.5 | 0.63 | (0.21–1.87) |
| Other | 40.5 | 1.28 | (0.86–1.89) | 46.3 | 1.02 | (0.68–1.55) | 54.7 | 1.03 | (0.66–1.59) | 33.6 | 1.18 | (0.75–1.84) | 2.6 | 0.43 | (0.14–1.32) | 1.3 | 0.56 | (0.17–1.86) |
| Caucasian | 34.6 | 1.00 | (referent) | 47.7 | 1.00 | (referent) | 55.5 | 1.00 | (referent) | 31.6 | 1.00 | (referent) | 4.8 | 1.00 | (referent) | 2.7 | 1.00 | (referent) |
| Employment, hours/week | ||||||||||||||||||
| ≥40 | 45.6 | 1.18 | (1.01–1.39) | 49.2 | 1.16 | (0.98–1.37) | 51.6 | 1.00 | (0.82–1.22) | 33.2 | 1.11 | (0.91–1.36) | 6.1 | 1.52 | (1.11–2.08) | 3.0 | 1.75 | (1.08–2.84) |
| 0–39 | 31.9 | 1.00 | (referent) | 45.6 | 1.00 | (referent) | 54.2 | 1.00 | (referent) | 30.2 | 1.00 | (referent) | 3.8 | 1.00 | (referent) | 2.4 | 1.00 | (referent) |
| Institution type | ||||||||||||||||||
| 2-Year College | 39.9 | 1.15 | (0.97–1.37) | 49.0 | 1.07 | (0.90–1.26) | 52.1 | 0.86 | (0.72–1.02) | 34.3 | 1.20 | (1.01–1.43) | 5.9 | 1.76 | (1.22–2.54) | 2.7 | 1.17 | (0.71–1.91) |
| 4-Year College | 30.9 | 1.00 | (referent) | 44.3 | 1.00 | (referent) | 54.8 | 1.00 | (referent) | 27.9 | 1.00 | (referent) | 3.1 | 1.00 | (referent) | 2.4 | 1.00 | (referent) |
legend CI, confidence interval; OR, odds ratio adjusted for gender, age, race/ethnicity, employment, and type of college attended;
∗ p < 0.05.
a Based on self-reported height and weight, overweight was defined as body mass index (BMI = weight [kg]/height [m]2) ≥ 25.0 and included students who met the definition of obesity (BMI ≥30.0) using guidelines proposed by the National Institutes of Health for adults aged 18 years and older.
b To lose weight or keep from gaining weight, during the past 30 days.
Finally, we used logistic regression models to determine the types of physical activity and food choice behaviors associated with specific weight management goals and practices, controlling for demographics (Table 4). Among female students, trying to lose weight was associated with participation in vigorous physical activity (OR = 2.86), strengthening exercises (OR = 2.34), and consumption of ≤ 2 servings/day of high-fat foods (OR = 1.58). Trying to stay the same weight was associated with participation in vigorous physical activity, strengthening exercises, and consumption of ≥ 5 servings/day of fruits and vegetables. Among male students, trying to lose weight and trying to stay the same weight were both associated with participation in vigorous physical activity, strengthening exercises, and consumption of ≤ 2 servings/day of high-fat foods. Among male students, participation in vigorous physical activity and strengthening exercises also were associated with trying to gain weight.
Table 4Prevalence and adjusted OR for physical activity and food choice among female and male undergraduate college students, by weight management goals and practices—United States, 1995
| Category | (n) | Physical activity | Food choice | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Vigorous | Strengthening | Moderate | ≥5 fruits & vegetables | ≤2 High-fat foods | |||||||||||||
| % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | % | OR | (95% CI) | |||
| Weight management goals | Females | ||||||||||||||||
| Lose weight | (1671) | 36.9 | 2.86 | (2.12–3.86) | 29.5 | 2.34 | (1.71–3.21) | 18.8 | 1.00 | (0.74–1.36) | 24.4 | 1.25 | (0.90–1.73) | 86.6 | 1.58 | (1.15–2.17) | |
| Stay same weight | (515) | 37.8 | 3.00 | (2.15–4.18) | 31.3 | 2.51 | (1.85–3.40) | 21.3 | 1.19 | (0.81–1.75) | 31.2 | 1.72 | (1.22–2.42) | 85.0 | 1.39 | (0.93–2.07) | |
| Gain weight | (98) | 18.0 | 1.16 | (0.55–2.45) | 13.9 | 0.94 | (0.45–1.98) | 17.8 | 0.84 | (0.45–1.59) | 26.7 | 1.41 | (0.79–2.52) | 75.5 | 0.87 | (0.48–1.59) | |
| Do nothing about weight | (534) | 17.8 | 1.00 | (referent) | 15.7 | 1.00 | (referent) | 19.0 | 1.00 | (referent) | 20.4 | 1.00 | (referent) | 80.3 | 1.00 | (referent) | |
| Weight Management Practices | |||||||||||||||||
| Exercise: | Yes | (1723) | 46.3 | 6.92 | (5.40–8.86) | 37.4 | 5.75 | (4.26–7.76) | 21.8 | 1.57 | (1.21–2.03) | 27.8 | 1.53 | (1.24–1.87) | 87.4 | 1.58 | (1.20–2.09) |
| No | (1090) | 10.7 | 1.00 | (referent) | 9.2 | 1.00 | (referent) | 14.9 | 1.00 | (referent) | 20.4 | 1.00 | (referent) | 80.4 | 1.00 | (referent) | |
| Diet: | Yes | (1163) | 40.1 | 1.76 | (1.46–2.11) | 32.0 | 1.64 | (1.31–2.05) | 20.5 | 1.15 | (0.93–1.42) | 27.4 | 1.21 | (0.99–1.48) | 87.0 | 1.33 | (1.07–1.66) |
| No | (1655) | 27.8 | 1.00 | (referent) | 23.1 | 1.00 | (referent) | 18.4 | 1.00 | (referent) | 23.3 | 1.00 | (referent) | 83.1 | 1.00 | (referent) | |
| Diet pills: | Yes | (203) | 33.3 | 1.05 | (0.77–1.42) | 30.9 | 1.30 | (0.91–1.87) | 17.0 | 0.86 | (0.58–1.28) | 18.1 | 0.68 | (0.44–1.07) | 91.0 | 2.13 | (1.21–3.75) |
| No | (2617) | 33.0 | 1.00 | (referent) | 26.5 | 1.00 | (referent) | 19.5 | 1.00 | (referent) | 25.5 | 1.00 | (referent) | 84.3 | 1.00 | (referent) | |
| Vomiting or laxatives: | Yes | (122) | 47.6 | 1.83 | (1.21–2.75) | 47.9 | 2.46 | (1.65–3.65) | 23.1 | 1.23 | (0.68–2.24) | 27.4 | 1.33 | (0.70–2.52) | 89.1 | 1.53 | (0.83–2.82) |
| No | (2693) | 32.3 | 1.00 | (referent) | 25.9 | 1.00 | (referent) | 19.2 | 1.00 | (referent) | 24.9 | 1.00 | (referent) | 84.6 | 1.00 | (referent) | |
| Weight management goals | Males | ||||||||||||||||
| Lose weight | (512) | 47.0 | 2.21 | (1.63–3.00) | 33.9 | 1.77 | (1.28–2.45) | 19.0 | 0.98 | (0.70–1.36) | 27.7 | 1.04 | (0.73–1.48) | 73.6 | 1.50 | (1.07–2.10) | |
| Stay same weight | (391) | 49.0 | 2.18 | (1.52–3.11) | 35.2 | 1.71 | (1.18–2.48) | 22.6 | 1.16 | (0.79–1.71) | 30.3 | 1.21 | (0.85–1.72) | 74.1 | 1.58 | (1.11–2.25) | |
| Gain weight | (354) | 51.8 | 2.22 | (1.58–3.12) | 47.0 | 2.69 | (1.86–3.90) | 16.9 | 0.82 | (0.54–1.25) | 29.3 | 1.19 | (0.86–1.63) | 64.4 | 1.06 | (0.74–1.53) | |
| Do nothing about weight | (477) | 30.3 | 1.00 | (referent) | 23.6 | 1.00 | (referent) | 19.7 | 1.00 | (referent) | 25.3 | 1.00 | (referent) | 65.1 | 1.00 | (referent) | |
| Weight management practices | |||||||||||||||||
| Exercise: | Yes | (735) | 58.5 | 3.12 | (2.40–4.06) | 44.9 | 2.40 | (1.86–3.09) | 22.6 | 1.42 | (1.11–1.82) | 32.3 | 1.43 | (1.11–1.84) | 73.5 | 1.40 | (1.12–1.75) |
| No | (998) | 32.5 | 1.00 | (referent) | 25.7 | 1.00 | (referent) | 17.1 | 1.00 | (referent) | 24.5 | 1.00 | (referent) | 66.4 | 1.00 | (referent) | |
| Diet: | Yes | (294) | 55.1 | 2.03 | (1.46–2.82) | 44.4 | 1.95 | (1.44–2.65) | 22.0 | 1.27 | (0.94–1.72) | 31.7 | 1.18 | (0.86–1.61) | 79.8 | 1.78 | (1.31–2.43) |
| No | (1440) | 41.2 | 1.00 | (referent) | 31.7 | 1.00 | (referent) | 19.1 | 1.00 | (referent) | 27.2 | 1.00 | (referent) | 67.4 | 1.00 | (referent) | |
legend CI, confidence interval; OR, odds ratio adjusted for age, race/ethnicity, employment, and type of college attended;
∗ p < 0.05.
a Exercised or took part in sports that made them sweat and breathe hard for at least 20 minutes on ≥3 of the past 7 days.
b Did muscle strengthening or toning exercises, such as push-ups, sit-ups, or weight lifting on ≥3 of the past 7 days.
c Walked or bicycled, including to or from class or work, for at least 30 minutes at a time on ≥5 of the past 7 days.
d Ate ≥5 servings of fruit, fruit juice, green salad, or cooked vegetables yesterday.
e Ate ≤2 servings of hamburger, hot dogs, sausage, french fries, potato chips, cookies, doughnuts, pie, or cake yesterday.
f Response to question, “Which of the following are you trying to do about your weight?”
g To lose weight or keep from gaining weight, during the past 30 days.
Physical activity and food choice behaviors also depended on the type of weight control method used (Table 4). Among female and male students, using exercise to lose weight or to keep from gaining weight was associated with participation in vigorous physical activity, strengthening exercises, and moderate physical activity, as well as consumption of ≥ 5 servings/day of fruits and vegetables and ≤ 2 servings/day of high-fat foods. Associations between exercise for weight control and participation in vigorous physical activity and strengthening exercises were greater among female than male students. Use of diet for weight control was associated with participation in vigorous physical activity and strengthening exercises, and consumption of ≤ 2 servings/day of high-fat foods among both female and male students. Among female students use of diet pills was associated with only consumption of ≤ 2 servings/day of high-fat foods. Female students who vomited or took laxatives for weight control were more likely than those who did not to participate in vigorous physical activity and strengthening exercises. Male students who reported using diet pills (n = 23) and vomiting or laxatives (n = 12) for weight control were too few to allow stable estimates of association with physical activity and food choice behaviors.
Despite recommendations for achieving weight loss through a combination of physical activity and healthy food choices, among students who were trying to lose weight, only 53.8% of females and 40.9% of males reported using both exercise and diet for weight control (Table 5). One of seven (15.2%) female students who were trying to lose weight used extreme methods (i.e., diet pills, vomiting, or laxatives) for weight control. Finally, only about 1 of 3 students who was trying to lose weight reported ever receiving any information from the college or university on the topics of physical activity and fitness or dietary behaviors and nutrition. Among those who were trying to lose weight, students attending 2-year colleges were less likely than students attending 4-year colleges to receive information on physical activity (31.3% ± 4.2% vs 41.8% ± 4.3%) and dietary behaviors (26.2% ± 3.8% vs 39.8% ± 3.9%) from their schools.
Table 5Exercise and diet for weight management, extreme methods for weight management, and health information received among undergraduate college students who were trying to lose weight, by gender—United States, 1995
| Category | Students who were trying to lose weight | |||||
|---|---|---|---|---|---|---|
| Total population (n = 2197) | Female (n = 1671) | Male (n = 512) | ||||
| % | (95% CI) | % | (95% CI) | % | (95% CI) | |
| Exercise & diet for weight management | ||||||
| Exercise and diet | 50.2 | (47.8–52.6) | 53.8 | (50.8–56.9) | 40.9 | (35.8–45.9) |
| Exercise only | 30.5 | (28.3–32.7) | 26.4 | (23.8–28.9) | 41.4 | (36.7–46.1) |
| Diet only | 8.6 | (7.4–9.8) | 10.0 | (8.4–11.6) | 5.2 | (3.1–7.3) |
| Neither | 10.7 | (9.3–12.1) | 9.8 | (8.2–11.4) | 12.5 | (9.5–15.6) |
| Extreme methods for weight management | ||||||
| Diet pills, vomiting, or laxatives | 12.1 | (10.4–13.8) | 15.2 | (13.0–17.4) | 4.7 | (2.4–7.0) |
| Health information received | ||||||
| Physical activity & fitness | 36.8 | (33.7–39.8) | 35.5 | (32.2–38.8) | 40.6 | (35.3–46.0) |
| Dietary behaviors & nutrition | 33.3 | (30.6–36.0) | 34.5 | (31.8–37.3) | 30.3 | (25.5–35.0) |
legend CI, confidence interval.
a To lose weight or keep from gaining weight, during the past 30 days.
b Reported ever receiving information on these health topics from their college or university.
Discussion
Based on self-reported height and weight, 35% of undergraduate college students in the United States were overweight or obese (BMI ≥ 25.0), and nearly half (46%) of all students were trying to lose weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Among female and male students, trying to lose weight was associated with participation in vigorous physical activity and strengthening exercises, and consumption of fewer high-fat foods, but not with participation in moderate physical activity or consumption of ≥ 5 servings/day of fruits and vegetables. Only 54% of females and 41% of males who were trying to lose weight used both exercise and diet for weight control.
Many of the nation’s undergraduate college students are placing their health at risk through lifestyle choices that include insufficient physical activity and unhealthy food choices, which results in a high prevalence of overweight. While prevalence estimates may vary in response to survey methodology and differences in the wording of questionnaire items, data from the YRBSS (self-administered written responses), Behavioral Risk Factor Surveillance System (telephone interviews), and National Health Interview Survey (household interviews), provide useful comparisons of physical activity and dietary behaviors among high school students, undergraduate college students, and the general adult population. The prevalence estimate for participation in vigorous physical activity among college students (38%) fell between prevalence estimates for high school students (64%)
21
and the general adult population (15%).8
Similarly, participation in strengthening exercises among college students (30%) was less common than it was among high school students (50%),21
but considerably more common than it was among the general adult population (14% reporting any strengthening activities in the prior two weeks).8
Moderate physical activity was measured by only 2 types of activity (i.e., walking and bicycle riding), so this item may underestimate actual involvement in moderate physical activity. However, the prevalence estimate for this question among college students (20%) was similar to that among high school (21%) students,21
and similar to estimates of regular, sustained (≥5 times per week for ≥ 30 minutes per occasion) physical activity among adults (22%) in national surveys that take other types of activity into account.8
Consumption of ≥5 servings/day of fruits and vegetables was more common among college students (26%) than the general adult population (20%),22
and consumption of ≤2 servings/day of high-fat foods was more common among college students (78%) than among high school students (60%).21
Although the prevalence of overweight was less among college students than the general adult population, 60% of female students and 30% of male students were trying to lose weight, compared with 33% of women and 20% of men in the general population.11
Before considering the implications of our findings, several limitations in the data must be acknowledged. Methods for the measurement of physical activity, dietary behaviors, and overweight are complex and often controversial. Our study was conducted as one component of the YRBSS. The data were self-reported and only a limited number of questions were available to measure these variables. The YRBSS estimates daily fruit and vegetable consumption with 4 food-frequency questions. Although the YRBSS questionnaire has been shown to underestimate fruit and vegetable intake when compared to multiple 24-hour dietary recalls, the YRBSS estimates of median daily fruit and vegetable intake and the prevalence of consumption of ≥ 5 servings/day of fruits and vegetables were similar to estimates produced by other brief food-frequency surveys.
23
The YRBSS estimates intake of high-fat foods with only 3 food-frequency questions, and will also underestimate the consumption of high-fat foods identified by more extensive dietary assessment methods. Fortunately, associations between the weight management goals and practices of college students and the food choices they make remain valid as long as consumption of fruits and vegetables, and high-fat foods are systematically underestimated. The prevalence of overweight based on self-reported BMI also is probably underestimated, because persons consistently underreport their true weights by approximately 1 kg.24
However, correlations between reported weights and measured weights are typically quite high, ranging between r = 0.96 and r = 0.99.24
Finally, the data are cross-sectional and cannot be used to imply a causal relationship between the decision to use a particular weight management method, and participation in various physical activity and food choice behaviors. Despite these limitations, our findings have important implications for the role of colleges and universities in preventing overweight and promoting healthy weight management among students.Our findings suggest that colleges need to implement new programs or improve existing programs to increase student awareness of healthy weight management goals and practices, and the importance of combining physical activity with healthy food choices. Nearly half of all students were trying to lose weight, yet only about 1 of 3 students who were trying to lose weight reported ever receiving any information from their college or university on the topics of physical activity and fitness or dietary behaviors and nutrition, and many of these students failed to adopt weight management methods consistent with current recommendations for healthy weight loss (i.e., combining exercise with diet). In addition, 15% of female students who were trying to lose weight used potentially harmful and unhealthy weight control methods (i.e., diet pills, vomiting, or laxatives). The fact that 60% of female students were trying to lose weight although only 30% were overweight (according to BMI) suggests that some weight loss efforts among female students reflect body image problems that may benefit from counseling services.
Programs to prevent overweight and promote healthy weight loss should encourage physical activity and emphasize foods to include as well as foods to limit. Moderate physical activity (e.g., walking) can be an effective method of increasing caloric expenditure, and fruits and vegetables can be an important component of a nutritionally rich, low-fat, low-calorie diet. Yet, we found that neither moderate physical activity nor consumption of ≥ 5 servings/day of fruits and vegetables were associated with trying to lose weight among college students. Interventions that emphasize the role of physical activity in weight management are especially needed among minority female students who were less likely than white female students to use exercise to lose weight or to keep from gaining weight. In our study, use of exercise for weight control was associated with participation in vigorous, strengthening, and moderate physical activity, as well as increased consumption of fruits and vegetables and decreased consumption of high-fat foods. Associations among participation in physical activity, increased consumption of fruits and vegetables, and decreased consumption of dietary fat have been noted in research involving the general adult population.
25
, 26
Healthy weight management programs for college students should discourage reliance on diet pills or dangerous purging behaviors in the place of appropriate physical activity and healthy food choices, especially among women and students who are employed full time. Among female students, use of diet pills for weight control was not associated with participation in physical activity, and vomiting or laxative use was not associated with healthy food choices. The association of vomiting or laxative use for weight control with participation in vigorous physical activity and strengthening exercises may reflect a syndrome of disordered eating among women that includes excessive use of exercise to expend calories.
27
, 28
Greater reliance on extreme weight control methods among students who were employed full time may be the result of increased time-pressures faced by these students at school and work.Conclusion
College campuses provide an ideal forum for reaching large numbers of young adults with education and prevention programs that promote healthy weight management. In addition to vigorous physical activity, strengthening exercises, and limited consumption of high-fat foods, students should be encouraged to incorporate moderate physical activity and sufficient consumption of fruits and vegetables into their weight management strategy. Additional efforts to discourage potentially dangerous and unhealthy weight control methods should be directed at female students and students who work full time. Campus health promotion programs should be coordinated with community and workplace programs, especially at 2-year colleges where students are often older, employed full time, and attending school part time. Programs that encourage healthy weight management through physical activity and healthy food choices should be expanded and integrated into all phases of campus life as part of a comprehensive health promotion plan for students. Efforts to impact student knowledge, attitudes, and behaviors should begin during the orientation process and continue through ongoing student services, physical education classes, and outreach activities. Colleges should implement professional and peer-led programs that combine outreach, education, and referral services, and offer required courses that provide experiential education in physical activity and nutrition.
Acknowledgements
Presented in part at the 126th Annual Meeting of the American Public Health Association, Washington, DC, November, 17, 1998.
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© 2000 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.
