Ultra-processed foods are linked to obesity in Australia

March 11, 2021

Have you ever heard about the term ‘ultra-processed’ foods? Perhaps not, but you are likely to have seen these foods before. These packaged foods are widely available in supermarkets, and are increasingly dominating our diets. In Australia, ultra-processed foods already make up nearly half of what we eat. Unfortunately, this level of ultra-processed food consumption is not good for our health, or the environment. Results of this Australian-first study to explore the links between ultra-processed food consumption and obesity are concerning and researchers urge for effective policy actions to address this issue.

Ultra-processed foods are ‘formulations of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes’.

Fast food dishes, confectionary, soft drinks, salty snacks, biscuits, flavoured milk drinks, instant noodles and many breakfast cereals, mass-produced breads and microwaveable frozen meals are examples of ultra-processed foods. When you go to the supermarket and you find a long list of chemical-sounding names in the ingredients list of a product, it is likely to be an ultra-processed food.

You may recognise many of these foods as ‘junk food’, or ‘processed foods high in salt, sugar and fat’. But almost all food is processed in some way. What researchers are really concerned about is the degree and purpose of the processing itself, in particular ultra-processing.

 Food is more than the sum of its nutrients: or, why ultra-processing really matters

Food is more than the sum of its nutrients

 Just for a moment, think of how many different cuisines and culturally important foods can be found around the globe. It’s so diverse, isn’t it? Authors say that these different traditional diets did not happen by chance. They resulted of our interactions with the environment and with each other, so we could find the best combinations for our wellbeing.  Foods also evolved providing what is best for us.

Foods are non-random complex mixtures of compounds. For example, the benefits of whole fruits and vegetables intake cannot be replaced with supplementation of the same amount of fibre and vitamins from pills. Only recently it was discovered that several benefits from fruits and vegetables come from phytochemicals that are protected within the fibre of the produce’s ‘food matrix’. When this complex matrix enters our bodies intact, beneficial bacteria are able to break down the fibre and safely release these compounds in the right place and time. How amazing! That’s why it is too simplistic to think of a food as merely the sum of its nutrients, because even the same nutrient might have different functions depending on where it came from.

Another important point when considering the impact of ultra-processed foods is that they are very similar around the globe. This is because it’s much more profitable to produce and advertise foods on a global-scale. Ultra-processed foods are often manufactured by ‘Big Food’ corporations using similar ingredients and similar market strategies (see our recent study on this topic). The problem is that to making highly-profitable, branded, convenient and attractive foods has very high costs for our health.

Processing techniques used in the manufacture of ultra-processed foods often destroys the food matrix, stripping out vitamins, minerals, phytochemicals and removing all the beneficial synergistic effects of foods. Manufacturers try to put some nutrients back in to ultra-processed foods by fortifying them with ‘positive’ nutrients, though this approach doesn’t really work. High amounts of chemically-altered ingredients (e.g. hydrogenated oil, high fructose corn syrup, protein isolates) are produced by extrusion, high-temperature heating and other high-tech processes. They are combined with several cosmetic additives (e.g. colours, flavours, emulsifiers) and packaged in synthetic materials, increasing the exposure to pro-inflammatory, toxic and obesogenic compounds. Importantly, ultra-processed foods are engineered to be overconsumed and to replace fresh foods, in what is called the ‘substitution effect’.

Thus, since humans have evolved eating whole foods, and the exposure to ultra-processed foods is very recent in our history, the question remains: is the human body capable to deal with diets saturated with such products? Evidence has shown that the answer is no.

Ultra-processed foods and obesity in Australia

Ultra-processed food consumption is increasing worldwide, including in Australia. Nearly half of what Australians eat is ultra-processed but the impacts of these foods have rarely been studied in this country. Australia has the fifth highest rate of obesity among the OECD (Organisation for Economic Co-operation and Development) countries. Obesity and poor diets increase the risk of developing many chronic conditions, such as diabetes, cardiovascular diseases and cancer.

To explore this topic, we used data from the National Nutrition and Physical Activity Survey, part of the most recent Australian Health Survey, which looked at the eating habits and health indicators of more than 7000 Australian adults. We divided the population according to different levels of ultra-processed food consumption and checked their body weight, height and waist circumference. We found that people whose diets included large amounts of ultra-processed food were 61 per cent more likely to be obese, have a higher Body Mass Index (BMI), and a larger waist circumference than people whose diets include less ultra-processed food. We found that even consumers with lower intakes of ultra-processed foods have a considerable risk of obesity, which indicates that there’s no safe level for ultra-processed food consumption.

So how to avoid ultra-processed foods?

 First, it’s difficult to eat less of something that is so available, affordable and heavily marketed. That’s why we need public policies that support the population to avoid ultra-processed foods. Unfortunately, existing Australian food and nutrition policies that focus nutrients in isolation (food reformulation, nutrient-based food labelling) are not effective. Dietary guidelines should categorically stress the avoidance of ultra-processed foods. Additionally, these foods should be banned from school and work canteens, marketing directed at children should be restricted, and front-of-pack labels should help easily identify ultra-processed foods.

We face unprecedented pandemics of obesity, chronic diseases, and environmental degradation. We need to promote sustainable, healthy diets to help ensure human and planetary health for generations to come. We hope our findings can support new approaches to tackle the harms of ultra-processed food consumption in Australia and globally.

Dr Priscila Machado is a Research Fellow in the Institute for Physical Activity and Nutrition and member of the Food Policy and Public Health group. Her research focuses on understanding the role of ultra-processed foods in human and planetary health, and on evidence synthesis and translation for food and nutrition policy.