The present study evaluated the effectiveness of a class based nutrition education in college students in their willingness to change food intake to achieve weight loss and to improve general health habits and assessed differences in body composition of study subjects. This research found that exposure to a class based nutrition education for college students induced transitional changes including: decrease of calorie intake, increase of skeletal muscle content and improvement of nutritional habits to help body weight management and meet the recommendations of proper food and nutrient intake.
The most remarkable finding during the nutritional education in this study was the reduction in total energy intake of study subjects. Initially consumption of energy and nutrients of study subjects was similar to the calorie intake of college students reported in previous studies. For example the study of Hong et al. (2012) reported that the average consumption of total calorie in Korean college female students in nutrition education program was in range of 1707 ± 344 kcal [17
]. Also, the average total energy intake of Korean male college students was 1695.2 ± 51.9 kcal [18
]. Overall nutrients and caloric intake, and food consumption is high in obese subjects, explaining their consumption of certain nutrients and vegetables to be higher. The magnitude of reduction in energy intake after nutrition education in this study was much higher than other study [19
] which explored the effect of nutrition education on weight loss. On the other hand, this study did not show much improvement in food consumption while Ha et al. [20
] showed that taking a general nutrition course at college enhanced students' fruit and vegetable consumption after nutrition education. Since the magnitude of calorie reduction is relatively high in this study, the overall food consumption was decreased and led to the reduction in certain types (e.g. cereal) of food which is usually a main source of energy.
The present investigation resulted in significant increases in skeletal muscle content which usually occur in conjunction with the increase of body water content as a part of transitional changes to acquire desirable body composition during weight management activities [10
]. Those changes, however, are usually accompanied with the increases of energy intake in study participants [21
]. Since the energy intake is much reduced in this study, the subtle changes in muscle contents of the subjects may not be due to nutritional education but may be due to a change of other behavior such as an increase of physical activity or an increase of hydration rate which has been known to increase of skeletal muscle mass [19
]. Though this 13 weeks intervention of nutrition education did not reduce body weight, the increase of muscle content and improvement in nutritional behavior of the subjects in this study still suggest that this class based nutrition education at least induced promising changes in weight and general health management.
This finding is consistent with previous studies that showed positive changes in dietary behavior such as an improvement in regular meal time and the utilization of nutritional knowledge after nutrition education interventions with college students [6
]. At the beginning of the study, only 13% of total study participants ate more than one serving of fruit per day, though the average consumption of fruit (0.4) was similar or less than previous studies [20
]. After the coursework this number increased up to 26%. However, overall, study participants did not meet the recommended intake of most type of food in this study. The effectiveness of nutrition education in weight management, food choice and nutritional behavior was well addressed in a wide range of literature [27
]. For example, school based nutrition education decreased soft drink consumption but increased milk and dairy products in female and male college students [27
]. Nutrition education via e-mail supply improved the intake of dairy products and self regulation strategies to increase low fat dairy products [28
]. Also, improved nutritional knowledge and confidence in the adequacy of their diet after completing a basic college nutrition course was reported [29
]. The elective course work regarding diet and weight management in this study was composed of discussing strategies how to prevent weight gain, fat accumulation and how to improve body weight in the context of food and nutrition intake. In addition, class lectures not only encouraged students to try to reduce body weight and calorie intake, but also motivated them to change overall eating behaviors and their lifestyle by using a variety of class activities and contents (self diagnosis of their stress levels, calculate proper energy need based on their physical activity etc.). This approach may have helped students relate the class material more directly to their own dietary habits, thereby giving them more awareness and motivation to change their own dietary behaviors. However, the changes scored in nutrition behaviors are subtle in this study compared to previous studies which assessed the effect of nutrition education on nutrition or health behaviors [6
] indicating efficacy of the course work in this study was weaker than that of previous studies.
This study also revealed a few limitations. Male and female students are obviously different in nature in anthropometric conditions and nutritional requirement. Also, several researchers have demonstrated that males tend to resist changing their habit and social pressure for health conscious but females have a relatively positive attitude toward healthy eating and behaviors than male students [20
]. Though a paired comparison was applied to assess the effectiveness of nutrition education on weight management and behavior in each participant, the result of this study could not differentiate gender differences due to the small number of study subjects. Also students enrolled in the elective course work may already be more conscious about a healthy diet and weight management compared to typical college students. This may lead the result that students were more amenable to respond to course work. In addition, this study could not adjust housing, economic status and social environment of each subject which could be a confounding factor in assessing the effectiveness of this coursework based nutrition education on body composition and nutrition intake [32
]. Importantly, results of this study could be biased due to the lack of a "control" group who was subjected to the same anthropometric and dietary assessments without receiving a nutrition education through participating elective course work. These caveats should be considered in future nutrition education intervention by incorporating effective and specific tools reflecting gender differences or each different social status for motivating nutrition behavior.
In conclusion, this research suggested a possibility that class-based nutrition education intervention could lead to an improvement of weight management, body composition, nutrition intake and behavior. Particularly for college students, this result is important since their health habits in this life cycle may extend to their whole life, could affects health of our society in the context of their influence of dietary habits to their household. Though this 13-weeks nutrition education did not reduce the body weight of the subjects in this study, students gained positive conciousness for a desirable weight management and body composition by an increase of muscle content and a decrease of energy consumption. These short-term transitional changes suggest that course work based nutrition education with academic commitment could be a time and cost effective way to improve body composition and nutritional behavior in college students regardless of their major, housing status, gender, and year in college. Future research should account for the limitations of this study in large sample size, follow-up study after nutrition education and adjusting social and family status of participants to validate the long-term effects of a course work based nutrition education on changes in dietary behavior.