Why we need to be talking about food quality

Over the past few years, the conversation around nutrition has shifted from discussing nutrients to discussing food itself. While the flawed health star rating continues for now, there are conversations starting to happen about the food matrix and overall food quality.

Firstly, it’s important to note that food processing has had a significant positive impact on human development for 1.7 million years. Initially, simple processing methods like cooking and salting helped improve food safety and increase shelf life. However, modern laboratory technologies have begun turning some of our food into “food-like substances,” which are highly accessible, convenient, and profitable to manufacturers. This shift towards ultra-processed foods is leading to an increase in health problems, including weight gain and metabolic disorders.

Watch Associate Professor Caryn Zinn’s full talk on Food Quality from The Future of Medicine Conference 2022.



The Nova food classification system

Nova is a food classification system developed 12 years ago by Professor Carlos Monte from Brazil with 4 basic food groupings. Group 1 includes whole unprocessed or minimally processed foods. Group 2 comprises culinary ingredients like oils, fats, and sugars. Group 3 consists of processed foods, where group 2 is added to group 1 with some processing. Group 4 is ultra-processed foods that contain many additives and involve extensive processing, otherwise known as junk food. Although Nova has not been validated in the literature, it is being used worldwide, and it’s nice to see a shift towards a system that focuses on food quality instead of nutrient-focused guidance that is often complicated and inaccurate.

Best in class dietary guidelines

The Brazilian food-based dietary guidelines changed after Nova was developed, with five of the ten guidelines emphasising the importance of eating whole and minimally processed foods and avoiding ultra-processed foods. These guidelines are now considered some of the best in the world as they focus more on behaviors and food quality rather than numbers and thresholds.

So, what exactly are ultra-processed foods? They are ubiquitous, they’re prolific, and their consumption is increasing, while the consumption of whole foods is decreasing. In New Zealand, 85% of our supermarket shelves are made up of ultra-processed foods. Of course, this is reflected in our consumption, and half of our children’s calories are now coming from ultra-processed foods.

The impact of ultra processed foods on food quality

Recent research conducted by Kevin Hall at the National Institutes of Health highlights the impact of ultra-processed foods on weight gain and overall health. Hall’s study consisted of a randomised controlled crossover trial, which included 20 individuals who were randomly allocated to an ultra-processed food diet or a minimally processed food diet for two weeks. The diets were matched for energy macros, meaning they had the same carbs, protein, fat, and fibre. The only difference between the two diets was the level of processing. The ultra-processed food group tended to increase their calorie intake by about 500 while they were eating, whereas the minimally processed food group tended to eat less calories, which translated to a weight gain of around a kilo in two weeks for the ultra-processed group and a loss of about a kilo in the other group.

Although the study suggests that calories do play a significant role in weight loss or gain, it is not the only factor to consider. Ultra-processed foods may have a detrimental effect on metabolic health, and there is independent research that shows that fructose has a detrimental effect on metabolic health by increasing the risk of non-alcoholic fatty liver disease, visceral adiposity, and metabolic syndrome. Additionally, the form of carbohydrate we consume can affect metabolism, with cellular carbohydrates like fruit and starchy vegetables having a different presentation in the body hormonally and metabolically compared to processed carbohydrates like grains and wheat.

Furthermore, additives like emulsifiers and antioxidants in ultra-processed foods can also cause metabolic dysfunction, including endocrine disruption, insulin resistance, and leptin resistance. The processing of foods can also cause metabolic disruption, as heat treatment or other processes can disrupt the matrix of the food. The structure of the food itself also influences energy balance, with research showing that the structure of almonds, for example, can affect the metabolic contribution and calorie content.


Ultimately, the implications for the future of medicine are all about conversations. We all need to have conversations at every level about food quality, including clinical practice, whether you are a dietician, health coach, GP, dentist, practice nurse, or pharmacist. If you have an opportunity to talk about food, take it to food quality. 


Associate Professor Caryn Zinn is a registered dietitian, academic at Auckland University of Technology, PREKURE Faculty member and Future of Medicine 2022 speaker. If you’d like to see more world class speakers talk about the future of medicine, check out the Future of Medicine Conference 2023. Learn more here.

Learn more about the nutrition short courses and certificates taught by Caryn Zinn.

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