The catering sector plays an important and increasing role in relation to people's food intake in Western countriesReference Burns, Jackson, Gibbons and Stoney1–Reference Roos, Sarlio-Lahteenkorva and Lallukka4. The French Public Health Society concludes that without working closely with caterers, a nutrition policy is unlikely to be successful5. In particular, the worksite setting has the potential of providing access to nutritious foods for a wide range of the adult population through canteens, meal vouchers, vending machines offering healthy options or simply provision of bowls of fruitReference Katz, O'Connell, Yeh, Nawaz, Nijke and Anderson6–Reference Wanjek8. However, relatively few studies deal with food selection and the nutritional quality of the food served away from home, and little is known about strategies to increase the nutritional value of the meals and encourage people to make healthier food choicesReference Roos, Sarlio-Lahteenkorva and Lallukka4, Reference Glanz and Hoelscher9.
While some dietary interventions in both the worksite and school settings have been quite promising in influencing employees and pupils to purchase and consume more healthy mealsReference Story, Snyder, Anliker, Weber, Cunningham-Sabo and Stone10–Reference Beresford, Thompson, Feng, Christianson, McLerran and Patrick13, other studies have been less positiveReference Parker and Fox14–Reference Steenhuis, Van, Reubsaet and Kok16. The most effective ways of achieving dietary changes seem to be increasing the accessibility and appeal of healthy choices rather than promoting ‘healthier’ menu items through nutrition labelling17, Reference Stubenitsky, Aaron, Catt and Mela18. In addition, food pricing has been suggested to be an effective tool to affect food choices, and large effects of price reduction on sales of fresh fruits and vegetables in two school cafeterias have been demonstratedReference French19, Reference French20. It is also likely that the meal service system influences the selection and hence consumption of different menu items offered in catering establishments. The worksite canteens in Denmark normally use one of two different self-service styles; either mainly buffet style or an à la carte line. The aims of the present study were to (1) evaluate the nutritional composition of worksite canteen lunch intake with regard to energy intake, energy density, macronutrients and the content of fruit and vegetables; and (2) examine the impact of two different meal serving systems on employee food choices and nutrient intake, i.e. buffet style with a fixed price for a varied number of dishes and à la carte style with a separate price for each item on the menu.
Methods
The recruitment took place in two steps. A total of 23 worksites with in-house catering facilities representing both city (Aarhus) and provincial towns were asked to participate in a survey describing the menus and serving system in the canteen. The worksites were extracted at random from a central national register. Worksite information was obtained on size, occupation (percentage physically active), sex distribution and canteen serving system to make sure that the final distribution would match that of the country as a whole. Two worksites refused to participate because of lack of time and one worksite was excluded to match the desired average distribution. A total of 20 worksites agreed to participate. Afterwards the 20 worksites were asked to participate in the present study focusing on individual canteen food intake. Five of the 20 worksites refused to participate for the following reasons: lack of time (three worksites) or concerns regarding the employees' reaction to the study (two worksites). Eight of the worksites that agreed to participate mainly served buffet style and seven of the worksites served an à la carte line. Data collection took place between February and November.
The duplicate-portion technique with subsequent chemical analysis was used to quantify actual lunch intakes at the worksite canteens. Double portions were collected from a total of 12 customers at each canteen on two different days (six samples per day). Employees were asked at random if they would participate in the study, and two people at most at each canteen declined to participate. Dishes identical to those selected by the employees were observed and collected by laboratory technicians. Both the original and the duplicate portions were photographed. After the employees had finished eating their lunch, they were asked to return the plates to the technicians in order to record plate waste. Food items on each dish, excluding plate waste, were weighed separately. Recipes and methods for dish preparation were provided by the staff of the canteens, thereby providing the basis for the calculation of the fruit and vegetable content of each dish. Beverages were not included in the analysis.
The portions were individually mixed and homogeneously blended. Analyses of the content of protein, fat and ash were performed according to procedures given by the Nordic Committee on Food Analysis21–23. Dry matter content was determined by drying in a vacuum oven at 70°C to constant weight. Carbohydrate and energy content were calculated from contents of dry matter, protein, fat and ashReference Saxholt and Møller24.
The participants in the survey were asked questions about their age, weight, height, employment, their attitudes towards eating healthy food, satisfaction with the canteen food and finally if the tested meal was a typical meal. The question ‘Do you try to eat healthy foods?’ could be answered as follows: ‘very often/always’, ‘often’, ‘sometimes’, ‘seldom/never’ or ‘don't know’. The question ‘Overall, how satisfied are you with the cafeteria food?’ could be answered on a 5-point rating scale from 1 = ‘very dissatisfied’ to 5 = ‘very satisfied’. Finally, the question ‘Does the actual meal resemble your usual meal?’ could be answered as follows: ‘yes totally’, ‘yes almost’ or ‘no not very much’.
Data analysis
Body mass index was calculated from self-reported height and weight data. Intake of fruit and vegetables was expressed in terms of both gram per meal and per 10 MJ. Dishes were categorised into three groups: (1) hot meals or sandwiches (mainly open sandwiches) only; (2) salad only; and (3) a combination of hot meals/sandwiches and salad/fruit/snack vegetables.
SPSS version 13.0 was used for the data analysis. Analyses were conducted separately for men and women, with the individual employee being the unit of analysis. Continuous variables were compared using the independent samples t-test when the data were distributed normally, i.e. age; and the Mann–Whitney U-test when data were skewed, i.e. body mass index, satisfaction score and measures of food and nutrient intake. The χ2 test with Yates continuity correction was used to compare discrete data variables, i.e. the prevalence of white collar employees and positive answers to the question ‘Do you try to eat healthy foods?’ Statistical significance was assigned to a P-value of < 0.05.
Results
Most of the respondents (94%) answered ‘yes totally’ or ‘yes almost’ to the question: ‘Does the actual meal resemble your usual meal?’ while 6% answered ‘no not very much’ to the question. No significant differences were found between employees having lunch at canteens serving buffet style and those having lunch at canteens with an à la carte line with respect to the tested background variables: age, body mass index, prevalence of white collar employees, satisfaction with the canteen food or how often they try to eat healthy foods. However, attitudes toward eating healthy food varied significantly by gender, as 80% of the women and only 48% of the men claimed that they often or very often tried to eat healthy foods (P < 0.001; not shown). Also, men had a higher calculated body mass index compared with women (25.3 ± 3.3 vs. 23.5 ± 3.9 kg m− 2, P < 0.001, not shown). Sixty-two per cent of all employees were white collar workers, average age was 40 ± 9 years and average satisfaction score was 4.2 ± 0.8 (not shown).
The nutrient intake is summarised in Table 1 by gender and meal serving system. No associations were detected between style of meal service and either energy intake or macronutrient distribution. The average lunch of the participating employees had 45 ± 13% of the energy from carbohydrates, 20 ± 7% from protein and 35 ± 12% from fat (Table 1). The average percentage of energy from fat was 37 ± 12 among men and 33 ± 12 among women (P < 0.05, not shown). Two-thirds of all dishes contained >30% energy from fat (not shown).
Table 1 Lunch intake at staff canteens of energy, macronutrients, fruit and vegetables for men and women by meal serving system
n – number of employees; SD – standard deviation; E% – percentage of energy.
Significant differences are highlighted in bold (P ≤ 0.05).
* Allow employees to pick and choose from a selection of different options for a fixed price.
† Employees pay for each item individually.
‡ Excluding potatoes.
Being a woman having lunch at canteens serving buffet style was significantly associated with eating larger food portion sizes (P = 0.003) with a lower energy density (P < 0.001) compared with canteens with an à la carte line, while energy intake did not differ significantly between groups (Table 1). With regard to the men, the energy density was significantly lower among those having lunch at canteens serving buffet style (P = 0.039), whereas average portion size did not differ depending on the meal serving system.
For both genders, lunch at canteens serving buffet style was associated with a significantly greater likelihood of consuming more fruit and vegetables (P < 0.001; g per meal and g 10 MJ− 1). On average, the men and women eating in canteens serving buffet style consumed 143 ± 101 and 174 ± 98 g of fruit and vegetables per meal, respectively (Table 1), corresponding to 78 and 71 g more, respectively, compared with those having lunch at canteens with an à la carte line (76 g more on average).
The pattern of food selection according to meal serving system is shown in Table 2. More employees having lunch at canteens serving buffet style selected a combination of different options including salad, fruit or snack vegetables (men and women: 63 and 75%, respectively, Table 2) compared with those having lunch at canteen with an à la carte line (men and women: 19 and 35%, respectively, Table 2), rather than eating either hot meals or sandwiches as the sole selection.
Table 2 Male and female employees' selection of different meal options, e.g. hot meals or sandwiches only, salad as sole selection or a combination of hot meals/sandwiches and salad/fruit/snack vegetables in relation to the meal serving system
n – number of employees.
* Allow employees to pick and choose from a selection of different options for a fixed price.
† Employees pay for each item individually.
Discussion
In this study of lunch intake in Danish worksite canteens, we found that eating at worksite canteens serving buffet style was significantly associated with an increased intake of fruit and vegetables compared with eating at canteens with an à la carte serving line. On average, employees having lunch at buffet-style canteens consumed 76 g more fruit and vegetables per lunch than those having an à la carte lunch. It is notable that the same pattern was found across genders, despite the fact that men compared with women generally consume less fruit and vegetables, as shown in this and other studies, and are less health consciousReference Ashfield-Watt, Welch, Day and Bingham25–Reference Friel, Newell and Kelleher27. The differences in fruit and vegetable consumption are comparable with the results of an intervention trial among employees including both individually tailored health messages and a helpers programme at the worksiteReference Campbell, Tessaro, DeVellis, Benedict, Kelsey and Belton28, and another including peer education to achieve an increase in fruit and vegetable intakeReference Buller, Morrill, Taren, Aickin, Sennott-Miller and Buller29. The Seattle 5 a Day Worksite Program focusing solely on changes in fruit and vegetable consumption in a wide range of worksite types, all with cafeterias, revealed an average increase of 0.4 servings in the intervention worksites from plate observation at cafeteria checkout linesReference Beresford, Thompson, Feng, Christianson, McLerran and Patrick13.
The present results suggest that the different patterns of food selection according to the meal serving system may account for some of the differences in lunch intake of fruit and vegetables. Serving buffet-style lunches seems to encourage people to combine different options, including salad, fruit and snack vegetables, and may increase the variety of the composed meal. Another possible benefit of serving buffet style is that the resources needed for cash handling may be diminished, enabling resources to be reallocated to prepare larger proportions of fruit and vegetables. It is important, however, that both canteens serving buffet style and à la carte lines focus on increasing fruit and vegetable content in the different meal options and at the same time try to limit the total energy intake.
Canteens with an à la carte line might be modified to promote fruit and vegetable intake without changing their serving style completely. Potential strategies to increase fruit and vegetable consumption could be selling a meal together with salad and fruit at a fixed price which is lower than the total of the à la carte prices of the same items. In a Danish canteen intervention study, an à la carte worksite canteen successfully offered a cold plate daily with a fixed amount of fruit and vegetables, e.g. 200 g of fruit and vegetables, including salads and half a piece of fruitReference Lassen, Thorsen, Trolle, Elsig and Ovesen12. Other obvious factors that can be affected are reducing the availability and attractiveness of competing unhealthy food options. Competitive food sold outside school meal programmes has been shown to affect students' food choices negativelyReference Kubik, Lytle, Hannan, Perry and Story30, Reference Probart, McDonnell, Hartman, Weirich and Bailey-Davis31, as the most popular choices are often foods with low nutritional valueReference Harnack, Snyder, Story, Holliday, Lytle and Newmark-Sztainer32.
The present results demonstrate, surprisingly, that the energy intake per lunch meal for both men and women is the same for both of the two different meal serving systems. Research has suggested that greater dietary variety is associated with greater food intakeReference Raynor, Jeffery, Phelan, Hill and Wing33, Reference McCrory, Fuss, McCallum, Yao, Vinken and Hays34. The present results showed that women chose larger food portions at buffet-style canteens offering a variety of foods for a fixed price but, since energy density at the same time was significantly lower, energy intake remained constant. The lower energy density was due to the increased amount of fruits and vegetables high in water and volume but providing less energy. It is likely that the energy density of foods is a key determinant of energy intakeReference Prentice and Jebb35. It has been found that when subjects ate a large portion of low-energy dense salad as a first course, energy intake for the entire meal was minimisedReference Rolls, Roe and Meengs36, Reference Ello-Martin, Ledikwe and Rolls37.
The Nordic Nutrition Recommendations state that fat should provide 25–35% of the total energy intake and that the population goal is 30%Reference Becker, Lyhne, Pedersen, Aro, Fogelholm and Phorsdottir38. In the present study, no relationship was found between fat content and the style of meal service. The average percentage of energy from fat was 37 ± 12 among men and 33 ± 12 among women. This is in line with the average percentage of fat found in the total diet among men and women in the Danish National Dietary Survey 2000–2002 when the contribution of energy from alcohol is excluded from the calculationsReference Andersen, Christensen, Groth, Fagt, Biltoft-Jensen and Hartkopp39. Also, data on average fat content expressed as gram per meal were in agreement with data from a study performed in Germany analysing staff canteen meals over a period of 1 yearReference Mayer40. On the contrary, a study performed in Croatia showed that 88% of the meals offered at students' restaurants provided a balanced intake of macronutrientsReference Baric, Satalic and Lukesic41.
The present study had both strengths and limitations. Strengths included that findings of employee lunch intake were based on portions that were weighed and analysed separately rather than on self-reported information. In addition, the survey imposed a minimum response burden on the employees, resulting in a high response rate. However, it cannot be excluded that the worksite canteens may have modified their meals slightly because of the survey and that employees may have changed their food choice behaviour on account of their meal being documented. Beverages were not included in this study, as the relationship between energy density and macronutrient content of beverages is more complex than that of individual foods or dietsReference Crowe, La Fontaine, Gibbons, Cameron-Smith and Swinburn42. Beverages, however, can make a significant contribution to the total energy intake of an individualReference Crowe, La Fontaine, Gibbons, Cameron-Smith and Swinburn42. Finally, no data are available on pricing of worksite lunches paid for individually by the employees. However, food choice is likely to be influenced by the price of the meal. Results from the first step of the recruitment survey showed that price variation was rather modest when purchasing meals in canteens serving buffet style compared with a larger variation when purchasing individual food items in canteens serving à la carte menuReference Hansen and Lassen43.
In conclusion, the results highlight the possibilities of promoting healthy food choices in the catering sector. The results also indicate the need for identifying models of healthy catering practice. There are a number of specific implications from this survey for improving canteen lunches. Attention should be paid to lowering the energy density of the food, motivating the employees to eat more fruits and vegetables, and lowering the fat content of the food without compromising the appearance or taste. Serving buffet-style meals including a variety of fruit and vegetables appears to be a promising strategy in order to increase fruit and vegetable consumption from food served away from home.
Acknowledgements
The authors would like to thank the employees who took part in this survey, the worksite canteens for their cooperation and the laboratory staff for collecting the samples and performing the laboratory analyses. We also thank Leif Bøgh-Sørensen, Anja Biltoft-Jensen, Lene Møller Christensen, Anne Vibeke Thorsen and Inge Tetens, all from the Danish Institute for Food and Veterinary Research, for their advice, support and manuscript review.
