Red for stop, green for go: Study measures effectiveness of colour-coded front-of-pack labels on consumer behaviour

By Gill Hyslop

- Last updated on GMT

The interpretive front-of-pack labelling system is resonating with consumers worldwide. Pic: GettyImages/KTSDESIGN SCIENCE PHOTO LIBRARY
The interpretive front-of-pack labelling system is resonating with consumers worldwide. Pic: GettyImages/KTSDESIGN SCIENCE PHOTO LIBRARY

Related tags HFSS front-of-pack labeling Traffic light labelling nutri-score Nutritional labelling World health organization Health Star Rating Chilean style warning consumer behaviour Health

A recent study has come out in favour of mandatory front-of-pack labelling (FOPL) policies – for both directing consumer choice and encouraging the food industry to reformulate products.

The 2021 study – published in PLOS Medicine – has confirmed the benefits of using colour-coded labels,​ noting they are instrumental in ‘nudging’ consumers towards choosing more healthful products and could be the underlying psychological mechanism towards cementing this behavioural change.

However, the scientists noted that each type of label had different attributes, which should be taken into consideration when making front-of-pack labelling policies according to local contexts.

Globally, the average consumer today typically indulges in a diet that is high in salt, sugar and saturated fat. Coupled with their habitual practice of low wholegrain intake, this has resulted in many living with major health complications, such as obesity, diabetes and heart disease. In 2019, nearly eight million deaths were attributable to dietary risk factors.

Providing consumers with clear information about the product’s nutritional profile products is recognised to nudge consumers towards more healthful food and drink choices and exert pressure on producers to ramp up their reformulation efforts.

Many countries have mandatory nutrition tables on the back of pack, but the World Health Organization (WHO) believes additional front-of-pack nutrition labelling (FOPL) is essential. It is the first thing a consumer sees and provides key info, such as calorie, saturated fat, salt and sugar content in a visible format.

FOPL generally falls into two main categories:

Interpretive labels present symbols, figures or cautionary text to indicate the overall healthfulness or nutrient content of a product.

Noninterpretive FOPL systems, such as the Guideline Daily Amount, convey nutritional content as numbers rather than graphics, symbols or colours, allowing consumers to create their own judgements on healthfulness.

Interpretive warning labels and colour-coded labels are the most adopted labels endorsed by governments around the world and include systems like Nutri-Score (France, Germany, Belgium, Netherlands, Luxembourg, Spain and Switzerland), Chilean style warning labels, Health Star Ratings (Australia and New Zealand), and the traffic light labelling system (UK).

However, real-world evidence over the effectiveness of the labels is limited and mainly focused on the Chilean style warning label. Observational studies found that Chile’s Law of Food Labelling and Advertising, which included the mandatory implementation of warning labels nationwide, resulted in lower sales of beverages high in sugars, salt, saturated fat, or energy and was likely to improve understanding and utilisation, especially in children.

However, to date, there is no data available on how these systems modify consumer purchasing behaviour, prompting this study.

What is the most effective?

The researchers analysed peer-reviewed studies to update knowledge of the most mainstream interpretive front-of-package nutrition labelling (FOPL) schemes, and found the traffic light labelling system (TLS), Nutri-Score (NS), nutrient warning (NW) and health warning (HW) were the most effective in directing consumers towards more healthful purchasing behaviour.

They grouped the outcome into three categories:

  • changes in consumers’ purchasing and consumption behaviour
  • consumers’ perception and attitudes towards products
  • consumers’ attention, understanding and perception of colour-coded and warning labels

This covered the probability of choosing less healthful or more healthful products, self-reported ratings of purchase intention, overall healthfulness of products purchased, and energy and nutrient (salt, sugar, fat and saturated fat) content of products purchased.

To explore the mechanisms underpinning behavioural changes (formation of attitudes), the group further assessed the influence of different colour-coded and warning labels on consumers’ perception and attitudes towards products based on perceived healthfulness and risks, perceived recommended amount and frequency of consumption, self-reported product appeal, and willingness-to-pay (WTP).

Results found that all colour-coded and warning labels were significantly associated with changes in purchasing behaviour, however, colour-coded labels (TLS and NS) performed better in promoting the purchase of more healthful products, while warning labels (NW and HW) had the advantage in discouraging unhealthful purchasing behaviour.

TLS, NS and NW all were associated with purchasing lower energy, salt, total fat or saturated fat and only one study suggested that TLS was not significantly associated with change in energy consumption.

According to the researchers, this provides the evidence to guide policymakers in choosing the optimal front-of-package labelling policies to help mitigate the burden of non-communicable diseases. However, they have recommended further studies to focus on the impact of FOPLs on dietary consumption in individuals, and industrial reformulation at the population level, especially in real-world settings and over a longer time frame.

Industry view

A proponent of the study is UK vegan and free from snack brand Gosh!, which uses a colour coded labelling system to clearly indicate its nutritional benefits to the consumer.

“We pride ourselves on being completely transparent with our consumers, and this is reflected in our labelling,”​ said William Topp, marketing manager of Gosh!

“Our labelling clearly shows the ingredients used in every product, whether that’s pulses such as chickpeas, lentils and beans; or vegetables such as beetroot, red pepper, carrots, onions, spinach, sweet potato, pumpkin, sweetcorn, butternut squash, cauliflower, peas, courgette, kale and mushrooms.

“The consumer can see and trust that any Gosh! product is made from only natural ingredients, is vegan friendly, free-from the top 14 allergens and holds no red traffic light allocations. Many of our products also provide sources of fibre and protein and some even contribute towards one of your five a day.”

Topp added Gosh! ramps up the feel-good factor with its mission to ensure the products are as good for the environment as they are for consumers' health.

“In addition to this, we are also committed to making all products sustainable. All of our packaging trays and sleeves are fully recyclable and made from predominantly recycled materials. Our latest innovations, Snack Bites and a frozen range, both come in 100% recyclable bags," ​said Topp.

“Therefore, not only do consumers know they are making healthier choices for themselves, but they are also contributing towards protecting their environment as well.”


Impact of color-coded and warning nutrition labelling schemes: A systematic review and network meta-analysis.

Authors: Song J, Brown MK, Tan M, MacGregor GA, et al.

PLoS Med 18(10): e1003765 (2021)

Related news

Show more

Follow us


View more