The rapid economic growth and westernized diet of Korea have triggered energy overconsumption [1], whereas the convenient modern lifestyle has led to the lack of exercise to increase metabolic syndromes, such as hypertension, diabetes and dyslipidemia [2,3]. Wilson et al. [4] defined metabolic syndrome as metabolic disorders that increase the risk of chronic diseases in which hypertension, hyperglycemia, dyslipidemia and abdominal obesity are simultaneously generated and progressed. Metablic syndromes are viewed as diseases that can be prevented by managing risk factors including obesity, drinking, smoking and wrong dietary habits to raise the importance of managing chronic illnesses and providing medical service [5].

The National Health Promotion Act enacted in 1995 regulates the nation and local autonomous entities to actively promote the regional society health project for improving the health of the public. This act has promoted the activation of health projects. As a part of the health project, nutrition education and consulting programs help subjects with nutritional issues to analyze their own dietary habits, learn proper living habits and solve problems. In particular, nutrition education provided in the workplace is especially beneficial to office workers that are unable to visit the hospital due to their work schedule. In the welfare aspect, it can also boost the work ambition of workers [6].

According to the study conducted by Lee & Suh [7], office workers began to become more interested in health as the society began to place greater emphasis on individual engagement and responsibility for health in relation to the increase in chronic diseases. However, due to various environmental factors, such as irregular work time, poor dietary habits, low nutrition knowledge, stress due to overwork and lack of health management efforts, chronic illnesses can be easily progressed among office workers. In fact, among chronic diseases, the prevalence rate of dyslipidemia is continuously increasing among men aged 30 and higher [8]. In particular, low HDL-cholesterolemia was increased from 22.8% in 1998 to 47.6% in 2007, thus presenting a 25.4% increase in 10 years (Ministry for Health, Welfare and Family Affairs & Korea Centers for Disease Control and Prevention, 2008). However, the opportunity of nutrition education, an essential factor in preventing and treating such diseases, remains insufficient [9].

According to precedent studies conducted on workers, providing a fixed period of nutrition education improved the dietary habits and lifestyles of subjects and positively influenced the clinical standard, thus reporting that significant effects can be acquired by implementing nutrition education in work places that provide at least one meal a day [10,11]. In a study conducted on office workers, Lee et al. [11] reported that providing a fixed period of nutrition education produced positive effects in reducing the weight and obesity of subjects, enhancing healthy behaviors and improving clinical standards [11-15]. In particular, by developing, systemizing and implementing an appropriate nutrition education program for workers according to workplace characteristics, the health conditions and the work morale of employees will be boosted increasing the pride for the company and productivity and reducing of national medical expenses. Furthermore, if the education content can be appropriately delivered to households, the nutrition education program implemented in the workplace after health check-up can also contribute to the improvement of domestic dietary life [16]. Thus, it is stipulated that providing an appropriate nutrition management education related with diseases and implementing continuous nutritional care and education through clinical nutritionists are not only essential for improving the health of office workers, enhancing company welfare and reducing medical costs, important for work efficacy. Furthermore, the role of the clinical nutritionist is to coach the subjects to independently find answers to change their dietary behaviors and maintain such changes in their dietary behaviors.

According to the results of the 2007 National Health Promotion Act, the obesity rate of Korean adults is gradually increasing from 30.6% in 2001, 31.5% in 2005 and 31.7% in 2007, along with the increased prevalence rate of obesity-related diseases. In case of metabolic syndromes, the prevalence rate of men have continuously increased from 20.8% to 32.9% after 1998 [17]. Furthermore, the study conducted by Bae et al. [18] on the changes in the obesity prevalence rate for 10 years (1997-2007) indicated that the obesity rate of men aged between 30-39 was increased 11.2% in a decade, from 20.7% in 1997 to 31.8% in 2007, whereas the obesity rate of men aged between 40-49 was increased 9.2%, from 25.6% in 1997 to 34.8% in 2007. The study also reported that it is necessary to evaluate and intervene dietary habits and health-related behaviors in order to reduce the obesity trend.

Hereupon, this study carried out health examination on male office workers with higher risk of having metabolic syndrome and classified subjects with abnormal findings (hypertension, diabetes, dyslipidemia, abnormal liver function indices). This study implemented the workplace-visiting nutrition education program based on the self-directed coaching method for changing poor dietary habits to proper dietary behaviors and attempted to analyze the effectiveness of the program.

Office workers frequently drink, dine out, miss breakfast, lack exercise and experience nutritional imbalance. The life style is formed based on such experiences cause chronic degenerative diseases including metabolic syndrome and cardiovascular diseases. during middle and old age. Nutrition education helps subjects to correct life styles to lower metabolic syndromes. Hereupon, among subjects that presented abnormal clinical findings in the health examination and comprehensive medical checkup implemented by the National Health Insurance, the workplace-visiting nutrition eduction was implemented for 75 male office workers, and the effectiveness was analyzed. We used self-directed coaching method based on metabolic syndrome components that each study subjects possess.

By analyzing the changes in anthropometric measurement, clinical and biochemical measurement before and after the 4-month nutrition education program, it is concluded that the body mass index (p < 0.05), fasting blood sugar (p < 0.01), total cholesterol (p < 0.05) and low density lipoprotein cholesterol (p < 0.05) were significantly reduced. The significant decrease in fasting blood sugar (p < 0.01) was similar to the study of Kim [19], which emphasized the significance of nutrition education and exercise in regulating blood sugar of diabetes patients. Decreases in serum lipid and total cholesterol is viewed as the effect produced by weight loss which is accomplished by nutrition education. The study conducted by Briley et al. [20] also indicated the decrease in weight and total cholesterol after nutrition education, and the study conducted by Epstein et al. [21] and Choi [22] also reported that weight loss can reduce total blood cholesterol and triglycerides concentration. Summer et al. [23] reported that the nutrition education provided for office workers was effective in reducing the weight and cholesterol standard of subjects. Low density lipoprotein cholesterol was also significantly reduced after nutrition education (p < 0.05), which is viewed to be related with weight loss.

The nutrient intake of subjects was presented as follows: calories 2160 kcal, carbohydrate 321.3 g, protein 79.7 g, fat 61.8 g. The ratio of carbohydrate, protein and fat to total calories was presented as 60%:15%:26%, respectively. When compared with the nutrient intake standard of Koreans (55-70%:7-20%:15-25%), subjects presented a higher fat ratio. Hunink et al. [24] reported that the increase in total fat intake increased the synthesis of chylomicron and very low density lipoprotein (VLDL) to increase the concentration of blood triglycerides and cholesterol. Subjects ingested 312.9 mg of total cholesterol, which is higher than the recommended intake for dyslipidemia patients (200 mg). The 2001 NCEP (National Cholesterol Education Program) reported that increased cholesterol intake in meals presented increased concentration of total cholesterol and low density lipoprotein cholesterol [25]. As results showed that subjects ingested 15.6 g of dietary fiber per day, which was 25 g less than the daily nutrient intake standard for Koreans [26], education to increase the intake of dietary fiber was also carried out during the nutrition education. The results of factor analysis, which influence clinical indicators related with metabolic syndrome after needs of providing, raise the needs of providing education on weight loss for subjecits with metabolic disorders.

However, the subjects of this study experienced difficulties in writing the meal journal during the basic survey. Requesting male office workers who possess low knowledge of food to write time-consuming meal journals can reduce the participation rate. In this regard, it is urgent to develop a program in consideration of the unique characteristics of subjects to help subjects to write easily and to view results immediately. Furthermore, to efficiently implement nutrition education to a large number of subjects in a fixed period of time, it is necessary to develop various nutrition education and assessment programs of outstanding quality and content to help subjects take interest and stay motivated. In addition, as the 4-month nutrition education effectively reduced body mass index, fasting blood sugar, total cholesterol and low density lipoprotein cholesterol, the nutrition education was verified to be effective in that experienced clinical nutritionists actively encouraged subjects through the self-directed coaching method. Thus, it can be stipulated that a customized nutrition education program must be implemented to reduce medical costs, improve work efficiency and enhance quality of life in the long run through enhanced health of subjects.

The results of this study verified that the visiting nutrition education provided to male workers through the individual-based, self-directed was effective in reducing body mass index and improving clinical quality index. In Korea, nutrition education and consulting have been mostly provided in hospitals. However, when considering the fact that the health of workplace workers, which compose a very large group, is directly connected with their work efficiency, it is important to achieve nutrition management through systematic education or consulting. Such nutrition education and consulting programs can be efficiently implemented by nutritionists within the workplace and thus requires the development of a program suitable for the workplace and the regular implementation of the program. However, as professional clinical nutritionists are absent in most work places, it is possible to consider the method of connecting hospitals with health check-up programs of work places. As health care professionals, nutritionists will actively contribute to the improvement of national health.