The HSR calculator is based on an algorithm that awards a star rating based on the quantity of specific food components within the product.
Generally speaking, foods with a greater proportion of nutrients of concern to public health, such as sugars and saturated fat, receive a lower rating than those with less.
Scores for each of these components are also weighted according to the extent of negative impact on your health at varying levels of intake.
At the lower end of the scale, saturated fat is weighted more heavily than sugars, and subsequently has a greater negative impact on the health star rating.
This is why some Greek-style yoghurts, many of which are comparatively high in saturated fats, receive a lower rating than lollies – despite the comparatively high sugar content of lollies.
The HSR system was intended to help consumers make comparisons in real-world situations where foods are usually compared against alternatives in the same category.
While a confectionery product may score 2.5 stars, within the category a score of 2.5 stars is rare, yet there are many yoghurts that will score higher than 2.5 stars.