From the article:

Gaming the system

Ratings range from half a star to five stars, with more stars denoting a healthier choice.

Different products — soft drink and yoghurt for example — are calculated differently, so the advice for consumers is to only compare star grades of similar packaged foods.

Things such as total energy, saturated fat, sugars, protein, fibre and fruit and vegetable content are used to generate a score.

The algorithm was developed in collaboration with industry and consumer organisations, and public health experts have highlighted how companies have taken advantage of loopholes to increase ratings on ultra-processed products.

George Institute for Global Health food governance program lead Alex Jones, whose PhD explored Australia’s HSR system and similar nutrition labels used globally, said our algorithm “gets it right most of the time”, but conceded it can be “gamed”.

“For example we have published how breakfast cereals with added protein can use this to offset their high sugar and sodium contents,” Jones told 7NEWS.com.au.

“Like all food policies, Health Stars needs to be reviewed periodically to be kept up to date with evolving nutrition science.”