N° 60 | October 2011

Positive changes in dietary behaviour among employees in blue-collar worksites: The Food at Work Study

Worksites as a health promoting platform

The worksite arena has been shown to be an excellent platform to efficiently promote positive and sustainable health behaviour modifications, including healthy eating among employees1-3. However, very few studies, especially European studies, have focused on promoting healthy eating in blue-collar worksites. The aim of the present Food at Work study4,5 was therefore to investigate opportunities and impacts of promoting healthy eating in blue-collar worksites using a participatory and empowerment research approach.

Food at Work - Study design

The Food at Work Study was conducted in Denmark in eight bluecollar worksites in a partnership with the General Workers’ Union. Worksites were stratified by company type and the presence or absence of a canteen, and randomly allocated to either an intervention group (five worksites) or a minimum intervention control group (three worksites). Intervention worksites were offered different kinds of hand-out materials focusing on simple and positive healthy eating messages. Otherwise, the project groups at each worksite were themselves responsible for implementing nutrition related activities addressing both the individual and the environment levels.

Evaluation methods

Different evaluation methods were used:

  1. Data on employees perspective collected through individual interviews among randomly selected employees following a structured questionnaire;
  2. Changes in employees’ dietary habits from baseline to end-point using four-day food diaries;
  3. The canteen nutrition environment as identified by chemical analyses of nutrient content in individual meal sélections using the duplicate plate method; and
  4. Semi-structured interviews with 23 key actors (project group members, e.g. union and manager representatives and cafeteria managers) conducted individually at end-point.

Positive attitudes among employees

Results showed that employees at the blue-collar worksites generally had a positive attitude towards the worksite promoting healthy eating, and that the degree of the positive attitude was increased over the project period (n=200, p=0,013). At end-point 93% of the employees agreed to some or to a high extend that the worksite should take part in promoting healthy eating.

Favorable changes in employees’ nutritional intake

In the intervention group (n=102) several significant positive effects in nutrient intake were observed among employees, including a significant median decrease in percentage of Energy obtained from fat of 2.2 (P=0.002) and a median increase in fibre intake of 3 g per 10 MJ (P<0.001). These changes were all significantly different from those seen in the minimum intervention control group. In addition, a significant median increase in fruit and vegetables was seen in the intervention group of 95 g per 10 MJ (P=0.002). Most of the increase in fruit and vegetable intake was accounted for by an increase of fruit intake by 74 g per 10 MJ (P=0.009).

Healthier canteen meals

A favorable change in the nutritional composition of the canteen meals in the intervention worksites with canteens was demonstrated, showing a median fat reduction of 11 E% of the meals selected by the employees (P<0.001, n=144). The canteen managers decided to focus on the reduction of fat content in the meals during the intervention period, and no significant change in fruit and vegetable content was found over time.

Important role of the union representative

The interviews showed that the involvement of the key actors was of major importance as to how the project developed at the different worksites. The union representatives generally played a central role in running the project, especially at the worksites without canteens. At the same time these worksites were associated with greater employee awareness and greater participation in the project activities compared to worksites with canteens. At worksites with canteens the canteen manager had a tendency to take charge of the project.


The study emphasizes the potential of engaging unions in worksite health promotion and demonstrates that moderate positive changes in dietary patterns can be achieved among employees in blue-collar worksites. Over time, this type of dietary change program has the potential for considerable access into communities and thereby contributing to a larger public health goal of reducing incidences of dietary related diseases and promoting healthy eating.

  1. Alinia S, Lassen AD, Krogsholm KS, Christensen T, Hels O, Tetens I. A workplace feasibility study of the effect of a minimal fruit intervention on fruit and nutrient intake. Public Health Nutr 2010; DOI: 10.1017/S1368980010002569.
  2. Lassen A, Thorsen AV, Trolle E, Elsig M, Ovesen L. Successful strategies to increase the consumption of fruits and vegetables: results from the Danish ‘6 a day’ Work-site Canteen Model Study. Public Health Nutr 2004; 7: 263-70.
  3. Thorsen AV, Lassen AD, Tetens I, Hels O, Mikkelsen BE. Long-term sustainability of a worksite canteen intervention of serving more fruit and vegetables. Public Health Nutrition 2010; 13: 1647-52.
  4. Lassen A, Bruselius-Jensen M, Sommer HM, Thorsen AV, Trolle E. Factors influencing participation rates and employees’ attitudes toward promoting healthy eating at blue-collar worksites. Health Educ Res 2007; 22: 727-36.
  5. Lassen AD, Thorsen AV, Sommer HM, Fagt S, Trolle E, Biltoft-Jensen A, Tetens I. Improving the diet of employees at blue-collar worksites: results from the ‘Food at Work’ intervention study. Public Health Nutr 2011; 14: 965-74.
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