Consumers can’t rely on Health Star Ratings

When chocolate drink Milo chose to remove its Health Star Rating from the front of its packaging in 2018, consumer advocates celebrated the decision as a win.

For years, Milo had proudly displayed a 4.5-star rating – marking it as one of the healthiest products in the drinks category – despite containing nearly 50% sugar.

The Health Star Rating scheme is used in New Zealand and Australia to help customers choose the healthiest product within a food category. The end goal is to reduce issues like heart disease, diabetes and obesity.

The scheme uses an algorithm to give foods a score based on their nutrient profile. It weighs the ‘‘negative’’ nutrients energy, saturated fat, sugars and sodium against the ‘‘positive’’ nutrients protein, dietary fibre, fruits, vegetables, nuts and legumes.

The scores are then displayed as a star graphic from 0.5 stars to 5 stars. The greater the number of stars, the healthier the product is overall. This is useful for deciding which is the best cereal for the kids – but you can’t compare ratings for cereal to yoghurt, for example.

In Milo’s case, the company attained its rating by displaying the number of stars awarded when the drink was made with skim milk. On its own, the powder only earns 1.5 stars. But rather than display a true reflection of its health value, Milo chose to remove the label.

Studies show that eight years after the scheme was adopted in a bid to create a healthier food landscape, its voluntary nature remains its downfall.

Less than a quarter of qualifying products on our shelves use the star ratings – and if they do, it’s most likely to be on ‘‘healthier’’ products such as high-fibre cereals, muesli bars or packaged fruit and vegetables. Companies’ least healthy products – like lollies, chips and biscuits – are much less likely to have a rating.

For example, one 2020 study into the impacts of food labelling found that more than 35% of products that achieved 4 or more stars displayed the label, compared to under 15% of those that were rated two stars or below.

But, crucially, that study also found that products that were labelled were 10% more likely to have changed the recipe of their product to get a higher rating.

One rationale for the Health Star Ratings was that it would encourage manufacturers to reformulate their products to make them healthier.

For example, since the ratings were introduced, the cereal Nutrigrain added fibre and lowered sugar to go from two to four stars. (Note: Nutrigrain remains more than 25% sugar).

Overall, the study said that foods with labels showed a 4% decrease in sodium content, and a 2% decrease in sugar content. (There were also increases in fibre content, an earlier study found).

The improvements were largest for the products that were initially very unhealthy. But because those products were less likely to adapt the labels, the health star scheme was yet to have a meaningful impact on the food landscape, researchers said.

This report was written with advice from Auckland University public health Professor Cliona Ni Mhurchu, who leads the Nutrition Research Programme at the National Institute for Health Innovation. It was reviewed by The Whole Truth: Te Ma¯ ramatanga expert panel member Associate Professor Lisa Te Morenga.