Just cut out processed foods if you want to be healthy. It’s an easy throw-away line loved by nutrition wellness influencers on social media, but such advice shows naivety for what happens to food in its journey to our plate. Almost everything you eat to some extent has been processed, and not all processed foods are bad for the body. Now nutrition researchers are better defining the world of processed foods and here, it is the new term of ‘ultra-processed foods’ that you will be seeing used more in the future. In this podcast, I look at what defines an ultra-processed food and explain how they are now recognised for the unhealthy addition they make to your diet.
Think the key to good health is to just ‘cut out processed foods’? The term ‘processed food’ may seem like a dietary demon that we need to avoid, but it is a concept that has little meaning and is unhelpful in informing food choices.
Almost everything you eat is processed to an extent. Even cooking food is a form of food processing. Unless you are eating only fresh fruits and raw vegetables, raw eggs and maybe raw fish and meat, then there is little in our diet that could be truly described as ‘unprocessed’.
A much more helpful concept is to divide food into categories based on their degree of processing. So, think more of food that has been minimally processed and is still close to its natural state in appearance and nutritional quality. Here it is all about fruits vegetables, fruits, wholegrains, nuts, milk, fresh meats and legumes. The sorts of foods featured in dietary guidelines. And against that, we have the foods we should be most concerned about: ultra-processed foods.
Nutrition science is now defining the processed foods we should be most concerned about. Ultra-processed foods are industrial formulations of food-derived substances that contain little if any whole food. Ultra-processed foods often include ingredients not commonly used in home cooking such as flavourings, colourings, emulsifiers and other additives. A key feature of ultra-processed foods is that they are usually appetising and pleasing to the taste buds, convenient, sold in large packages and highly marketed.
The category of ultra-processed foods emerged from an attempt to classify food by its level of processing by the NOVA food classification system. NOVA is a system of food organisation created by a team of nutrition and health researchers at the University of São Paulo. It is now recognised by global health agencies including the United Nation Food and Agriculture Organisation and used by many researchers globally. And I’ll link to a document that goes into greater depth about NOVA in the show notes http://www.fao.org/3/ca5644en/ca5644en.pdf
NOVA categorises food products by the extent and purpose of food processing as a proxy for the food’s nutritional and environmental characteristics. The NOVA system clusters food into four groups. And those groups are
NOVA Food Grouping | Examples
Group 1: Unprocessed and minimally processed food Characteristics: Minimal processing may include drying, pasteurisation, cooking and chilling. Examples: Fruits, vegetables, nuts, meat, eggs, milk, legumes, pasta, wholegrains and rice
Group 2: Processed culinary ingredients Characteristics: Undergo some processing to make products that can be used in cooking Group 1 foods but are not meant to be consumed by themselves. Examples: Oils, butter, sugar and salt
Group 3: Processed foods Characteristics: Usually made from two or three ingredients. Usually made by Group 2 substances added to natural or minimally processed foods (Group 1) to preserve or to make them more palatable. Examples: Preserved fruits and vegetables, canned fish, cured meat, cheese, fresh bread, beer and wine
Group 4: Ultra-processed foods Characteristics: Contain little, if any, intact Group 1 foods. These foods go through multiple industrial processes (such as extrusion, pre-prying milling) and contain many added ingredients with usually at least five or more ingredients. Colours, flavours, emulsifiers and other additives are often added to make products more palatable. Examples: Soft drinks, sweet/salty/fatty packaged snacks, confectionery, mass-produced breads/baked goods, cake mix, margarine and other spreads, sweetened breakfast cereals, pre-prepared meat, chicken ‘nuggets’, burgers, instant soups, packaged desserts, energy bars, baby formula and meal replacements
What sets ultra-processed foods apart from other foods is the extent and purpose of processing. Ultra-processed foods have a higher level of processing that changes the food and often stimulates overconsumption.
Ultra-processed foods are designed to be appealing, convenient to consume and palatable so are more likely to displace the consumption of healthier, less processed foods. The convenience of ultra-processed foods can mean people may choose them over foods that are healthier, but which require more preparation time and effort. A diet high in ultra-processed foods can mean people lose their skills and interest in making healthy dishes for themselves. Ultra-processed foods also produce higher profit margins for food companies which helps fuel big marketing budgets, further competing out interest in less processed foods by the consumer.
Ultra-processed foods are a big problem in the Australian diet with these foods contributing to over 40 percent of Australians’ daily energy intake. These foods are also key drivers of excessive sugar intake among all age groups. So, you can see how much of a problem eating too many of these foods can be.
Fast food, fast weight gain
Ultra-processed foods are the types of foods that are over-represented in the list of discretionary food choices. Such foods are not an essential part of a nutritious diet. Now nutrition health professional around the world are linking these foods as a major driver of overweight and obesity, while also contributing to non-communicable diseases such as heart disease, type 2 diabetes and certain cancers.
A diet high in ultra-processed food is linked to a greater chance of weight gain when eaten over the long term. A recent tracking study of over 6,000 adults in the United Kingdom, which I’ll link to in the show notes, found that over 8 years, people with diets high in ultra-processed foods were more likely to be heavier and have almost double the chance of becoming obese compared to people who ate the least ultra-processed foods. The more ultra-processed food a person ate, the greater their chance of becoming obese. For every 10 percent increase in the consumption of ultra-processed foods, the chance of being obese rose by a disproportional 18 percent. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194406
Then there was a study from Spain spanning over 7 years which also found a link between ultra-processed food consumption and health. A link to the study is in the show notes. A higher consumption of ultra-processed food to the extent it made up a third of a person’s diet was associated with a higher risk of earlier death. Poor diet is linked to many chronic diseases such as obesity, heart disease, type 2 diabetes and some cancers so this likely explains why people were dying at a younger age. https://www.sciencedirect.com/science/article/pii/S0025619619304185
Scientists are now looking deeper into what may be so insidious about ultra-processed foods that link them to weight gain. In a small, but important study which I’ll link to in the show notes, 20 people in a controlled inpatient environment spent two weeks eating either a highly processed or unprocessed diet. They then spent the next two weeks eating the opposite diet. While the degree of processing between the diets was very different, the kilojoules, sugar, fat, fibre and many other nutrients were identical. It was only when people were eating the highly processed food diet that they gained weight – almost one kilogram in the two weeks. And this weight gain was entirely explained by them eating a greater volume of food. Why did they eat more food? It seems because they tended to eat faster - potentially not allowing enough time for their body to signal to their brain that they were full. https://pubmed.ncbi.nlm.nih.gov/31105044/
Not a perfect system
The NOVA classification system of ultra-processed food is not a perfect guide and it does have its critics. Not all foods in the ultra-processed category need to be shunned as some of them can play an important role in providing nutrition. Infant formula is just one example. And while there are many poor choices on the market, some breakfast cereals are a good source of convenient nutrition. This is not surprising as NOVA classifies foods based on the extent and purpose of food processing, not by their nutritional merits.
As a concept though, grouping foods according to their degree of processing can be a useful guide to their likely effect on health. So, at a public health and policy level, it is a useful tool to help guide consumer food choices, inform food labelling changes and allow industry to work transparently in reformulating food into healthier and less processed ways.
Become a label reader
The NOVA classification system is seeing a lot of use by nutrition researchers and international organisations, but it is unlikely you will find anything related to it on food packaging in Australia any time soon. But with a bit of knowledge, you can apply the principles of NOVA to see which category a food would fit into. This is where becoming a food label reader pays dividends especially as most ultra-processed foods come in packaging that needs labels.
Look at the ingredients list of the food and ask yourself if all these ingredients would likely be found in a home kitchen? If the ingredient list is long, and many of the items don’t sound like food you would buy off the supermarket shelf, then that is a strong hint that you are looking at an ultra-processed food.
Most of the food we eat is processed to some degree. But it is only the foods considered to be ultra-processed that we should aim to eat less of. Eating food as close to its natural state as possible, making food from original ingredients and choosing a wide variety of mostly plant-based foods are the keys to eating a healthy diet.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.