A nutritious diet is important to the health and wellbeing of Australian and New Zealand consumers. Large studies around the world have reported that diets of lower quality (e.g. high in sugar, salt, and saturated fats) are associated with an increased risk of early death from cardiovascular disease and cancer.
Diet scoring systems
There is extensive research on ways to measure how nutritious your diet is. Diet scoring systems, also known as diet quality indices, typically rate the quality of your diet based on the different types of foods you eat – such as fruit, vegetables, cereals, meat and fish, and some also look at the nutrients we get from these foods such as sodium, sugars, protein, fibre and fats. For example, the CSIRO Healthy Diet Score is a survey that assesses eating habits against the Australian Dietary Guidelines. The closer you score to 100, the closer you are to meeting the Guidelines.
In Australia and New Zealand, food scoring systems are also used to determine the number of health stars on a food label, and whether a food is eligible to carry heath claims. Health claims are only permitted on foods that meet the nutrient profiling scoring criterion (NPSC).
Diet scoring systems were not originally developed to estimate how a person's diet may influence their risk of adverse health outcomes. For example the US Healthy Eating Index (HEI) was developed in the 1990s to monitor changes in US dietary intake over time, and as the basis of nutrition promotion activities for the population. Subsequent studies then investigated associations between diet quality scores and adverse health outcomes. Regardless of the scoring system, however, it is recommended that a balanced and healthy diet is consumed and this is best achieved through following national dietary guidelines.
There are other systems which categorise foods according to the level of processing they have undergone. The NOVA system, for example, has four food categories: (1) unprocessed or minimally processed foods, (2) processed culinary ingredients, (3) processed foods, and (4) ultra-processed foods. The NOVA system does not assign scores to foods or diets, but does state that ultra-processed foods are unhealthy and should be avoided.
Ultra-processed foods are defined in the NOVA system as typically containing 5 or more ingredients, including substances extracted from foods and substances derived from further processing of food components. Ultra-processed foods can also contain food additive classes such as colours, flavours, non-sugar sweeteners, and processing aids.
Examples of ultra-processed foods include carbonated drinks, sweet or savoury packaged snacks, ice-cream, chocolate, confectionary, mass-produced packaged breads and buns, margarines and spreads, sausages, and burgers. Several studies have reported that diets high in ultra-processed foods are also associated with an increased risk of death from cardiovascular disease and cancer.
FSANZ has carried out a significant amount of work comparing studies linking diet and health outcomes in which diet quality was assessed using conventional food/nutrient scoring systems and also using the NOVA system. We limited our analysis to consideration of mortality, cardiovascular disease, cancer, obesity and metabolic syndrome. Papers from several very large studies in Europe and the US have reported information of this nature.
We found that, based on the available evidence, all scoring systems gave similar findings. For example, people with diet quality scores in the lowest 25% in food/nutrient scoring systems have about the same increased risk of adverse health outcomes as people in the highest 25% of ultra-processed food consumption.
FSANZ will continue to monitor the emerging literature on diet scoring systems and NOVA.
More information on healthy eating is available at eatforhealth.gov.au and health.govt.nz.