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Action on Sugar

New Systematic Review and Meta-analysis Supports Call for Mandatory Front-of-Pack Labelling to Improve Diets

  • A NEW systematic review and meta-analysis supports the call for mandatory front-of-pack nutrition labelling to help shoppers make, and the food industry provide, healthier choices
  • The UK’s Traffic-light Labelling System, Nutri-Score, Chile-style Nutrient Warning Labels and Health Warning Labels were all able to direct consumers towards more healthy purchases
  • Much of the existing evidence on front of pack labelling is based on short-term computer simulations; more evidence on the real-world impact of labelling is needed
  • Action on Salt and Sugar (based at Queen Mary University of London) is now calling for the UK Government to make front-of-pack nutrition labels mandatory without delay

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A NEW systematic review and meta-analysis led by researchers from Action on Salt and Sugar based at the Wolfson Institute of Population Health, Queen Mary University of London and published today in the PLOS Medicine Journal (Impact of color-coded and warning nutrition labelling schemes: A systematic review and network meta-analysis)1 supports the call for mandatory front-of-pack nutrition labels in directing consumers towards healthier options.

The network meta-analysis summarised the current available 134 studies, nested in 120 peer-reviewed articles, to update the knowledge of the most mainstream ‘interpretive’ front-of-pack nutrition labelling schemes (i.e. those that use colours, symbols or graphics to aid consumers in understanding nutrition information).

It found that the UK’s Traffic-light Labelling System (TLS), Nutri-Score (NS), Chile-style Nutrient Warning labels (NW) and Health Warnings (HW)2 - all examples of interpretive front-of-pack labelling - were all able to direct consumers towards more healthy purchases, reducing the energy, salt, fat or saturated fat content of processed foods and drinks chosen or purchased.

Prior to this study, evidence on the impact of each type of colour-coded label and warning labels on modifying consumers purchasing behaviours was mixed. This research demonstrates that all interpretive nutrition labels support consumers, but curiously, colour-coded labels (TLS and NS) perform better in highlighting positive aspects of products and encourage consumers to purchase healthier products. In contrast, warning labels (NW and HW) put the negative aspects of products front and centre which discourages the purchase of less healthy products.

Interpretive front-of-pack labelling is considered a cost-effective strategy to promote a more healthful diet and prevent diet-related disease3. The UK’s Traffic-light Labelling System has been in place in its current format since 2013, displaying levels of total fat, saturated fat, total sugar and salt in products colour-coded as either high (red), medium (amber) or low (green). While many UK food companies now display these labels, since it is a voluntary scheme around one in four products does not display them4. Colour-coded labelling is not present in the out of home sector either (i.e. restaurants, cafes, fast food outlets).

In 2020, the UK Government consulted on front of pack nutrition labels5, inviting views on the current Traffic-light Labelling System and a potential move to Nutri-Score or Chile-style Nutrient Warning Labels. However, this study found that much of the existing research on nutrition labels focuses on short term computer simulations. This research suggests future studies should focus on the real-world impact of nutrition labels on individuals’ eating patterns, and on industrial reformulation at the population level, over a longer timeframe.

Action on Salt and Sugar recommend that the Government make the UK’s current voluntary Traffic-light Labelling System mandatory across all products, including the Out of Home sector, as part of their response to the National Food Strategy6.  The scheme should be evaluated in real time to assess effectiveness in helping to prevent obesity and diet-related diseases such as stroke, heart attacks and various cancers.

Lead author Dr Jing Song, Postdoctoral Research Fellow at Queen Mary University of London said: “Despite the variation in label types, labelling formats, position, study population, study design and experimental settings across studies, our comprehensive systematic review and meta-analysis supports the call for colour coded front-of-pack nutrition labels, which all have positive effects on guiding consumers in making more healthful food choices. Food manufacturers must now get on board in efforts to improve the nation’s health by committing to putting front-of-pack labels across all their food and drink products and on menus.”

Mhairi Brown, co-author and Policy Manager for Action on Salt and Sugar said: “The Government’s recent consultation on front-of-pack nutrition labels invited views on different labelling formats but did not indicate their intention to make labels mandatory. This research provides clear evidence that labelling works. We are now urging the Government to make labelling mandatory across all products as this would force manufacturers to show consumers, at a glance, if the product is healthier or less healthy – and hopefully encourage them to reformulate to reduce levels of salt, sugar and saturated fat.”

Professor Graham MacGregor, Chair of Action on Salt and Sugar said: Policies that encourage food manufacturers to improve what goes into the foods we buy will help improve the nation’s diet. Suboptimal diets are a leading risk factor for death and disability and the Covid-19 pandemic has reinforced how vital it is for the Government to break the junk food cycle. The Government must commit to mandatory front of pack nutrition labelling as part of their response to the National Food Strategy - alongside comprehensive and strictly monitored reformulation programmes - to support the nation’s health”


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Notes to editors:

About Action on Salt and Sugar

Action on Salt is a group concerned with salt and its effects on health, supported by 22 expert scientific members. Action on Salt is successfully working to reach a consensus with the food industry and Government over the harmful effects of a high salt diet and bring about a reduction in the amount of salt in processed foods as well as salt added to cooking, and at the table.

Action on Sugar is a group of experts concerned with sugar and obesity and its effects on health. It is working to reach a consensus with the food industry and Government over the harmful effects of a high calorie diet, and bring about a reduction in the amount of sugar and fat in processed foods to prevent obesity, type 2 diabetes and tooth decay.





  1. Song J, Brown MK, Tan M, MacGregor GA, Webster J, Campbell NRC, et al. (2021) Impact of color-coded and warning nutrition labelling schemes: A systematic review and network meta-analysis. PLoS Med 18(9): e1003765.
  2. Labelling schemes included in this research:

a. UK Traffic Light Labelling scheme uses green, amber and red to represent low, medium and high levels of fat, saturated fat, sugar and sodium per 100g/per 100ml on the front of food packages, respectively, with the addition of the % Reference Intake value for calories and each nutrient

b. Nutri-Score includes a colour spectrum ranging from dark green to dark orange with letters from A to E. Products assigned an “A” were considered to have the best nutritional quality while “E” the poorest

c. Chile-style Nutrient Warning labels are a type of nutrient warning with a textual warning “high in [calorie/nutrient]” presented on the octagonal signs in a black-and-white design

d. Health Warnings (example shown of State of California Health Warning label) are designed to inform consumers of any potential health risks associated with the nutrition content of products 

3. Guiding principles and framework manual for front-of-pack labelling for promoting healthy diet. World Health Organization; 2019

4. Childhood obesity – brave and bold action. First report of session 2015-16. 2015. The House of Commons Health Committee. HC 465

5. Front-of-pack nutrition labelling in the UK: building on success. 2020. Department of Health and Social Care, Department of Health (Northern Ireland), The Scottish Government and Welsh Government

6. In 2019, the Department for Environment, Food and Rural Affairs (DEFRA) commissioned Henry Dimbleby to conduct an independent review to help the Government create its first National Food Strategy for 75 years. This review was released in July 2021, highlighting the historic reform needed to protect the NHS, improve the health of the nation and save the environment. The Government has committed to responding with a White Paper within six months (i.e. by January 2022). We recommend that a legislative proposal for mandatory front of pack nutrition labelling should be included in this White Paper.



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