Energy intake and snack choice by the meal patterns of employed people

Recently the number of daily eating times has increased, while the number of cooked meals has declined in developed countries. This is probably a result of the increased availability of snack foods and snacking occasions [1]. The frequency of snacking has increased due to urbanization, industrialization and the convenience provided by food processing [2-4]. Among adult Finns more than half of them consumed only one or two meals [5]. In elderly Greeks, all subjects had at least one cooked meal a day, however only 50% of subjects had two cooked meals [6]. Although only 12.5% of the subjects do not eat snacks, the majority of US adults (62.3%) consumed two or more snacks [7].

Most snacks in the industrialized world have a high energy density and people do not fully compensate their energy intake after the consumption of snacks [8, 9]. Therefore, a more frequent consumption of high energy density snacks leads to an increase in daily energy intake [10], and the prevalence of obesity [11]. From previous studies, the average contribution of snacks to the daily energy intake was about 20-30% in western developed countries [12-14]. Food choices for a snack may facilitate an increase in energy intake. High fat desserts and salty snacks remain the most popular snack items [1, 15]. However, there is very little information regarding the contribution of energy intake from snacks and choice of snack foods for Korean adults.

One of the major social trends in present society is the increased participation of women in the labor force. As incomes rise and pressure on available time increases, working people want to do less cooking. Thus, there is a growing demand for snacks instead of conventional meals to provide nutrition and pleasure. Breakfast is most likely to be skipped among time-pressured employed people, which is associated with continuous snacking or frequent, light eating behavior [16]. Moreover, working adults more and more want to buy ready-to-eat take away dinners or home-delivered fast foods. Then, as a reward for making it through a tough day, some have heavy snacks while watching television at night. To the extent that people who work spend more time away from home, this trend is likely to continue [3]. As a result, the fundamental eating patterns of families with employed people are changing dramatically. Therefore, there is value in exploring eating patterns of employed people.

The aim of this study was to provide descriptive information on meal and snack patterns and to investigate snacks in relation to energy intake and food choice according to the meal patterns of employed people in Korea.

The results of this study provide descriptive information regarding meal and snack patterns and reveal specific meal and snack patterns associated with energy and macronutrient intakes of employed people in Korea. Our results showed that the number of eating occurrences per day varies roughly between 1 and 6, with an average above 4. However, a majority of the subjects (72.6%) adhere to the eating pattern of three meals per day regardless of the consumption of snacks. The common meal pattern in nearly half of the subjects (47.6%) was composed of three meals plus one or two snacks per day. This implies that a trend of an increasing number of snacks in between main meals emerges, although the conventional meal pattern is still retained by most employed Korean adults.

The proportion of three-meal eaters was 44% in Finns [5]. The majority of Swedes consumed only one hot meal and only 32% of Swedes consumed more than one cooked meal [17]. In elderly Greeks, all subjects had at least one cooked meal a day, however the proportion of people who consumed two meals per day was only 50% [6]. French adults had 2.7 meals and one or more extra-prandial eating events per day [18], Therefore, the proportion of 3 main meal eaters in this study was higher than majority of other western countries. Almost half of the subjects (49.9%) in our study tended to consume 2 or 3 snacks besides their main meals. The number of multiple-snackers was still low compared to the US and other western countries [7, 19]. Meanwhile, when our findings are compared with the results from an earlier study in Korea [16], the proportion of snackers who consume one or two snacks per day was 72.2%, which is higher than the figure in the present study. However, the proportion of multiple snackers who consumed snacks more than two times was only 0.5%. Moreover, the prevalence of non-snackers was higher in that study than ours. Thus, snacking has recently increased in Korean adults.

A specific meal pattern is often associated with certain demographic characteristics. The meal skippers who consume snacks frequently (≤2M+2,3S) and the most frequent eaters (3M+3S) were more likely to be female, urban residents, and 20 to 39 years old (Table 2). By comparison, the least frequent eaters (≤2M+0,1S) were more frequently male, rural residents, and between the ages of 20-29, or 40-49. Non-snack eaters (3M) could be observed in males, aged 40-49, and rural residents or residents of the large city. The prevalence of the MFSE was higher in women, aged 30-39, and urban residents than the LFSE. From these results, women aged 20-39 living in urban areas may possibly prefer snacks more than men, which is consistent with reports from other cultures [11, 19].

The results in our study show that increasing meal and snack eating occasions may be associated with higher energy, protein, and carbohydrate intakes, with the exception of fat intake (Table 3). The most frequent eaters (3M+3S) had 6 eating occasions per day, revealing the highest energy, protein, and carbohydrate intakes, followed by the values of the 5 times eaters (3M+2S). The least frequent eaters (≤2M+0,1S) had the lowest amounts of energy, protein and carbohydrates intakes. The results reported here are in agreement with other studies regarding energy and macronutrient intakes according to eating occasions [20, 21].

An important issue for research on the nutritional importance of snacks is the relationship between increasing snack frequency and energy intakes. The data presented in Table 4 indicates that 16.8% of the total daily energy intake came from snack consumption, while meals contributed 83.2%. The contribution of snack intake to total energy intake from northern European countries varies from 32-34% in Finland [5] to 22-23% in Sweden [12]. The British middle aged group consumed 21.4% (female) and 25.8% (male) of their total energy intake from snacks [13], while the contribution of snack intake to daily energy intake in young French adults ranged from 12% to 17%. Therefore, the proportion of snack energy intake in this study was lower than that found in the studies of other countries, although our data was similar to the result from France.

Energy and macronutrient intakes from snacks in the MFSE were significantly higher than those in the LFSE (Table 4). When the energy, and macronutrient intakes from snacks are compared with the 5 meal patterns, the values do not change proportionally despite an increase in eating occasions. This is because the proportion of the macronutrients in the meals and snacks were different from each other. Snacks are higher in carbohydrates and lower in protein and fat when compared with meals [13, 18]. Gatenby [22] reported that snacks were higher in carbohydrates and energy than meals although there is no difference in total fat content. Data from the United States [23] also show that snacks contain more carbohydrates but less protein and fat than main meals. Therefore, energy, protein, and fat intakes from snacks in the meal pattern of "≤2M+2,3S" were highest followed by the values of the "3M+3S" (Table 4) even though those values were not significantly different. Similarly, the energy, protein, and fat intakes from snacks in the "2M+0,1S" were higher. However, they were not significantly higher than the "3M+1S".

Another element in the discussion of the contribution of snacks to energy intake is the nature of the snack. Certain food groups are frequently consumed as snacks. The 3 most frequently consumed foods for the morning snack were coffee, milk/dairy product, and fruit/vegetable, which were the same as the foods for the afternoon snack. In addition, more carbohydrate rich foods like bread, rice cake, buchimgae, and sweet potato were consumed in the afternoon than in the morning. Although, food items consumed at main meals may differ by country, the type of snack foods consumed is not much different between countries [24]. Usually, coffee, tea, beverage, sweet bakery goods, and fruits are common snack items in various countries [11, 19, 20]. However, the item consumed by our subjects which varied the most from other countries was instant coffee. The contribution of the number of all tea and beverage consumed to the total frequency of snack foods in the morning and the afternoon was 11% and 10%, respectively. On the contrary, the frequency of instant coffee, as a single food item, contributes 36% in the morning and 35% in the afternoon. In other words, instant coffee was the most popular snack during day time in the present study. It is well known that instant coffee mix is the top sales item at "E-mart", which is one of the biggest supermarket chains in Korea [25]. This might be a specific cultural phenomenon in Korea. The majority of Koreans are accustomed to drinking hot soups and a bowl of hot rice tea during and after meals. Therefore, the hot temperature of coffee might be favorable to many Koreans. Besides a few factors like reasonable price and taste, convenience, and high availability may also contribute to the high popularity of instant coffee.

However, the kind of food eaten for snacks in the evening was quite different from that of the morning or afternoon. Instant coffee, which was the most popular item during the day time, was rarely consumed in the evening. Instead, alcohol and soft drinks were more frequent in the evening. Although the most common snack item was "fruits & vegetables", certain food items, for example, beer and roast chicken-were consumed mainly in the evening. In addition, these items are frequently high energy dense foods, for example, Tigim, roast or steamed pork, pizza, Ddockbokgy, and ramen. The typical explanation for the reason of consuming energy dense snacks in the evening is that people are used to relaxing with their family, and sharing preferred foods in a greater quantity after a long, stressful day. One other reason is that the omission of breakfast and lunch is likely to be compensated by overeating later in the day [26]. This is similar with other countries. Alcohol was mainly consumed with dinner by young French adults [27] and by elderly Greek rurals [6]. Therefore, it is common that energy intake increases when it is later in the day [28, 29]. A meal pattern shifted to later in the day is considered a possible causative factor for obesity [17, 21].

Moreover, the frequency of snack foods was significantly different among the 5 meal patterns (Table 7). Heavy snacks and alcohol were more frequently consumed in the two meal skipper groups (≤2M+2,3S and ≤2M+0,1S). On the contrary, fruit/vegetable and various snacks were frequently consumed in the three meal eating groups (3M+3S, 3M+2S, and 3M+1S). It means that meal skipping affected the frequency and type of evening snack. A lower eating frequency results in large fluctuations in blood glucose levels [30]. Moreover, skipping meals has been related to the consumption of higher energy and carbohydrate snacks in the afternoon and evening [26, 31]. Therefore, skipping a meal and eating snacks frequently could be classified as unhealthy food habits. The meal skippers who consume snacks frequently (≤2M+2,3S) in this study could be classified as one of the bad habit groups. Their energy and macronutrient intakes from snacks were the highest among all meal patterns (Table 4). Meal patterns have received little attention in nutrition studies. Therefore, further studies are needed on the effect of a meal pattern of three regular main meals and of the avoidance of frequent snacking in the prevention of obesity.

Findings from this study suggest that a trend of an increasing number of snacks in between main meals emerges, although the conventional three meal pattern is still retained by most employed Korean adults. Women aged 20-39 living in urban areas possibly prefer snacks more than men. 16.8% of their total daily energy intake came from snack consumption, which is not much higher than other western countries. Increasing meal and snack eating occasions is associated with higher energy, protein, and carbohydrate intakes, but not fat intake. Foods for the evening snack were significantly different by the meal and snack eating occasion. High energy dense foods were used as snacks in the evening by meal skippers. In conclusion, meal and snack patterns may be markers for the energy and macronutrient intake of employed people in Korea.