Another health charity has joined calls for immediate mandatory front-of-pack nutrition labelling to help consumers make healthier choices.

Colour-coded front-of-pack nutrition labels, in whatever form, all have positive effects on guiding consumers in making more healthy food choices and manufacturers must now commit to placing them on all their food and drink products and on menus, Action on Salt and Sugar said.

An analysis of 134 studies by the charity’s researchers published in the PLOS Medicine Journal found that the UK’s traffic light labelling system (TLS), Nutri-Score (NS), Chile-style nutrient warning labels (NW) and health warnings (HW) were all able to direct consumers to products containing less energy, salt, fat or saturated fat.

The study found colour-coded labels performed better in highlighting the positive aspects of products and encouraged consumers to buy healthier items, while warning labels made negative aspects of them “front and centre” and also discouraged the purchase of less healthy products.

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).

But it is a voluntary scheme and about one in four products do not display the labels. Colour-coded labelling is also not present in the out-of-home sector, such as in restaurants, cafes and fast food outlets.

In a 10-year strategy published last week, the Obesity Health Alliance also said much more was needed over the next five years to reverse rising obesity levels, including mandatory front-of-pack nutrient labelling.

The alliance, which includes the British Heart Foundation, Cancer Research UK, Diabetes UK and medical royal colleges, said successive governments have failed to tackle obesity since 1991, when ministers set the first target for reducing obesity rates in England to 7% (1980 levels) by 2005.

Action on Salt and Sugar has now recommended 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 Henry Dimbleby’s National Food Strategy report.

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.”