It has been pitched as an easy-to-read system to help shoppers make healthier choices at the supermarket, but a leading nutrition expert says the Health Star Rating still has serious flaws, and ignores a key risk facing Australians.

The star system assesses the overall nutritional profile of packaged food, assigning ratings from ½ star to five stars as a method to compare similar food items.

However, because of the way the stars are awarded, shoppers can still end up with an unhealthy product in their trolleys.

The George Institute for Global Health on Thursday continued its research into the star system, releasing a paper on its uptake by companies and understanding by consumers.

Since its introduction four years ago, the government-initiated, voluntary rating system only appears on one-third of packaged products throughout Australia, the institute found.

And, of those products that displayed their star ratings, most were at the upper end of the ranking system.

Not all is as it seems

While Deakin University Professor of Public Health Nutrition Mark Lawrence agreed with the concept of an easy-to-read health rating system, he said there were flaws with the way the Health Star Rating was implemented.

Professor Lawrence said the way the stars were calculated ignored the food product itself and concentrated on its nutrition – meaning it was out of step with the current and accepted nutritional science knowledge base.

“The rating doesn’t differentiate if these (nutritions) come from a healthy food or a junk food,” he told The New Daily.

“What we call discretionary foods – junk foods – are getting very high ratings of stars.”

The star system has been criticised in the past, most notably for awarding Milo a 4.5-star rating, a move it was forced to retract after lobbying from the health industry.

Milo’s controversial 4.5-star rating was removed last year. Photo: Milo Australia/Facebook

Professor Lawrence referenced muesli bars, which can regularly be slapped with a four-star rating, but are brimming with high sugar levels, and are highly processed.

“It’s giving (foods) a healthy halo,” he explained.

“People compare two products’ star ratings and think, ‘Oh this one is good’ – when really it’s only good in relative to the other one, which is really bad.”

Ignoring the real problem

One of the key issues facing Australia’s obesity epidemic is the rise of highly processed or ultra-processed foods, Professor Lawrence said.

His standpoint is backed up by US research that this month showed people who consumed more ultra-processed foods gained more weight than people who followed less-processed diets – even though their nutritional intake was on par.

“(This research) highlights a major nutrition science weakness with the health star rating system – it’s based on the amount of a limited number of nutrients in a food regardless of first determining whether the food is nutritious or ultra-processed,” Professor Lawrence said.

Until the Health Star Rating system is overhauled (the government is currently undertaking a review of the system, with recommendations due at the end of June) what’s the best way for Australians to shop healthy?

“The simple advice is: More often than not, look for less processed food. Avoid ultra-processed food, aim for minimally processed – and a variety of it,” Professor Lawrence said.