Obesity

Recent evidence suggests that more than half of the adult population in the U.S. is overweight or obese, with the percentages increasing significantly over the last 15 years (1). The number of children who are overweight or obese is also increasing at an alarming rate, with more than 17% of children in the U.S. being overweight or obese, and even higher percentages among African American and Hispanic children (1). Results from the Behavioral Risk Factor Surveillance Survey suggest that the greatest increases in obesity occur in individuals between the ages of 18 to 29 years, during the transition from adolescence to adulthood when many attend college (2). Physical inactivity, poor dietary choices, increased caloric intake, increased stress and disturbed sleep patterns, in addition to many other factors, contribute to the increased weight gain and obesity in college-aged young adults (3,4,5,6). In many cases, increased body weight contributes to the development of the metabolic syndrome in adolescents and young adults, including impaired glucose tolerance, insulin resistance, hyperlipidemia, elevated blood pressure, and increased abdominal fat (7,8,9,10,11). Reducing the amount of weight gained during adolescence and young adulthood by increasing physical activity and improving dietary choices may help to reduce the risk of diabetes and cardiovascular disease in adulthood.

The purpose of this review is to critically analyze the current evidence on the prevalence and risk of obesity as well as physical activity and dietary behaviors in the college student population. In addition, the review will address the issues in the development of successful nutritional and physical activity interventions designed to reduce the risk of obesity and increase physical activity in this population.

THE HIGH SCHOOL TO COLLEGE TRANSITION: THE “FRESHMAN FIFTEEN”

The transition from high school to college is one critical period in life where the risk of weight gain is significantly higher than other time periods (12,13). Weight gain for university women can be as high as 0.75 kg/month (approximately 9 kg or 20 lb per year), significantly higher than community-dwelling women of the same age (12,13). College freshman are exposed to a variety of new experiences and potential lifestyle changes that may influence their health and risk of obesity, including changes in eating habits, living environment, and daily physical activity, and possibly increased alcohol intake (14,15). In addition, increased stress associated with academics or life issues may also contribute to the risk of weight gain in college students (4,5,16). These changes in lifestyle and stresses may increase the risk of gaining weight during the first year of college, and thus increase the risk of becoming overweight or obese in adulthood.

Some controversy exists as to whether men and women gain weight during their first year of college. While some studies suggest that the amount of weight gained is not significant (17,18,19), other studies indicate that both men and women gain weight during the first year of college, although the amount of weight gained may be less than the fifteen pounds (approximately 7 kg) suggested by the “Freshman fifteen” (13,15,20,21,22,23). Some studies suggest that this weight gain occurs during the first year of college, with weight stabilization in the later years of college (12,13). In contrast, others observe a significant weight gain continuing into the sophomore year of college in both men and women (14).

A few of the studies suggest possible reasons that contribute to the weight gain during the freshman year. These include nutrition-related factors, such as increased consumption of junk food, recent dieting, increased snacking, and “all you can eat” dining halls (13). A significant decrease in physical activity, which results in a decrease energy expenditure and can result in a decrease in resting metabolic rate, may also contribute to weight gain in college (15,20,22). In addition, individuals with a negative body image, those who were overly concerned about their weight, or individuals who are responsive to external or environmental cues about food, such as the sight or smell of food, may be more at risk for gaining weight during the freshman year of college (18,24). Interventions designed to reduce weight gain need to address psychosocial, nutrition, and physical activity related factors in order to facilitate long-term healthy lifestyle behaviors in these young adults.