Table 1 Description of the intervention elements

Nutrition education

Group presentations: Monthly nutrition sessions (30 min per session) were delivered in the workplace by the FCW nutritionist. Topics included portion control, food labelling and general healthy eating guidelines. Sessions were repeated to ensure they were accessible to employees on different shift cycles.

Individual nutrition consultations: Participants received one-to-one dietary counselling with the FCW nutritionist. Consultations were tailored for each participant based on their lifestyle, physical assessment results and dietary recall assessments. The nutritionist provided advice on how to follow a healthy diet, reach/maintain a healthy body weight and achieve healthy resting blood pressure. Participants also received a healthy eating booklet and a personalised measurement card.

Detailed nutrition information: Detailed nutrition information was prepared by the FCW nutritionist and displayed in the workplace throughout the intervention. The information included posters, leaflets, emails and daily calorie menu labelling with a unique traffic-light coding system. A healthy eating chat table was also provided twice a month during break times to provide employees with an opportunity to ask the nutritionist about healthy eating.

Environmental dietary modification

Menu modification: Saturated fat, sugar and salt were restricted. Stock and bouillon were replaced with low-salt stock options. Salt was replaced with fresh herbs, spices and garlic for additional flavour. High salt savoury options, high-salt products and processed meats were reduced and replaced where possible with low-salt options. Full-fat dairy products were replaced with low-fat options where possible. Cream and cheese were not used as a garnish on meals and the amount of cheddar in all meals was reduced. Cooking methods using oil (deep-fat frying) were limited and replaced with boiling, poaching, grilling, baking and steaming where possible. Plant oils were introduced for cooking. Sauces and accompaniments were not added to any meal unless requested by the employee. Chips and French fries were removed from the menus 2 days a week and were replaced with different potato options such as baked potatoes. Soft carbonated drinks were restricted and replaced with water, milk and unsweetened options.

Increase in fibre and availability of fruit and vegetables: White pasta, rice and bread were replaced with wholegrain alternatives. Fruit and vegetables were added to rice, pasta, soup and meat dishes. Fresh whole fruit was made available throughout the day and a buffet-style fresh salad bar was available to accompany any dish on a daily basis.

Price discounts: Portions of whole fresh fruit were offered at discount prices on a daily basis within the confines of the pre-existing catering contract.

Strategic positioning of food: Healthier alternatives were strategically positioned throughout the workplace canteen. Healthy snacks, such as fresh fruit, dried nuts, seeds, brown sandwiches and brown soda bread were positioned at eye level at the entrance of the canteen and in the vending machines. Free-flowing salt and sugar were removed from tables and replaced with sachets.

Portion size control: Standard serving tools were used to control portion size at mealtimes. Catering staff received training from the FCW nutritionist regarding strict portion size control.