This article was written by Associate Registered Nutritionist (ANutr) Sophie Gastman, and reviewed by Registered Dietitian Maeve Hanan.
What Are Processed Foods?
When most people think of processed foods, they think of pre-packaged cereal or frozen pizza, but the criteria that classifies a food as processed often surprises people!
The real definition of a ‘processed food’ is ‘any food that has been altered in some way during preparation’ (1). This includes everything from freezing to canning, or even as basic as chopping (yes, even pre-cut fruit and veg are considered processed!).
As there is a wide variety within this group, a research team recently came up with the NOVA Food Classification System which grouped processed foods into four categories to help people understand the extent to which a food has been processed:
- Group 1 is for unprocessed or minimally processed foods. Unprocessed foods are foods straight from nature that don’t go through any processing such as fruit and veg, eggs, nuts, seeds etc. Minimally processed foods include things that may have been dried, fermented, frozen, boiled, or any other process but contain no added ingredients, e.g. pasteurised milk, 100% fruit juice, frozen fruit and vegetables etc.
- Group 2 is for processed culinary ingredients. This includes things like oils, butter, lard, sugar and any other ingredients that are used to season and cook food.
- Group 3 includes processed foods, which covers any product manufactured by the food industry with the use of salt, sugar, oil or other substances used to enhance taste or prolong its shelf-life. These foods are normally made using a mixture of group 1 and 2 ingredients, for example, smoked and cured meats, fresh bread, salted nuts etc.
- Group 4 is for ultra-processed foods. These are foods typically formulated with 5 or more ingredients, including preservatives, stabilisers and hydrogenated fats would fall into this category. A report on the consumption of ultra-processed foods in the UK between 2008-2014 showed that the most commonly eaten ultra-processed foods were industrialised bread, ready meals, breakfast cereals and sausages/other processed meat products (2).
The Stigma Surrounding Processed Foods
There’s a lot of stigma around processed foods or people who rely on processed foods, especially in the media. They’re often stamped with the label of being ‘lazy’ or ‘unhealthy’. What people fail to recognise is that it would be disordered to avoid all processed foods (or even just groups 3 and 4), and we can’t ignore the privilege needed to prepare most food from scratch in terms of finances, food availability, time availability, skills, knowledge, equipment etc.
It’s easy to remain in our own bubble and pass judgement, but imagine a parent of a child with autism who will only eat a specific brand of frozen chicken nuggets, or a person with a chronic illness who doesn’t have the energy to cook from scratch, or a family who can’t afford to buy fresh fruit and vegetables for fear of it going bad or their fussy children refusing to eat it, so they opt for frozen chips, pizzas, and ready meals instead, which they know will get eaten.
When you look at it from this angle, you realise that the blanket advice we normally hear dished out about ‘always making things from scratch’ or just ‘making healthier swaps’ isn’t really that helpful.
How Do Processed Foods Impact Health?
As explained earlier, food processing is a broad spectrum that ranges from basic processes like freezing to incorporating additives for shelf life – the health impacts of processed foods will of course depend on the type of processing.
There is evidence that consuming high amounts of ultra-processed foods is associated with certain worsened health outcomes such as cardiovascular disease and early death (3). A high intake of ultra-processed foods has also been linked with a greater consumption of added sugars and saturated fat and a lower intake of essential vitamins and minerals (4).
However, it’s important to note that the majority of studies in this field are observational and therefore cannot prove that the ultra-processed foods are a direct cause of any adverse health outcomes.
On the other hand, meals from scratch aren’t always more nutritious.
For example, one study compared the macronutrient content of TV chefs’ recipes to ready meals sold in supermarkets. They compared 100 recipes to 100 ready meals and discovered that the recipes contained significantly more energy, protein, fat, and saturated fat per portion, as well as less fibre (5).
A long ingredients list does not always mean a food is unhealthy either. For example, ascorbic acid (E300), cholecalciferol, ergocalcipherol and tocopherols are all just the chemical names for vitamins. These are normally added to foods to improve the nutritional content or to replace any vitamins lost during processing and there’s a lot of evidence that this practice has reduced the prevalence of nutrient deficiencies globally (6).
A really common misconception is that fresh is always best when it comes to fruit and veg, but this isn’t always the case!
Fresh produce starts declining in nutrients the moment it’s harvested, so whilst it’s sitting on the shelves or in your fridge, it’s gradually losing nutritional value. Freezing, on the other hand, stops this process in its tracks.
A study reviewing the different research into the nutritional content of fresh, frozen and tinned fruits and vegetables found that all the vegetables tested lost significantly less Vitamin C when they were frozen (7).
This means that some frozen fruit and vegetables are actually more nutritious (and cheaper) than fresh produce – a win win!
As mentioned above, the process of adding extra nutrients to a product (fortification) is a form of processing that adds extra nutritional value. For example, a more processed soya milk that’s fortified with calcium and iodine is more nutritious than a less processed organic soya milk that has no added minerals.
You may have heard that certain substances used in our foods are ‘toxic’ or ‘harmful to our health’, but in reality, there are strict regulations and laws about what and how much can legally be put in our foods in order to protect the health of consumers.
The international body that addresses the safety of food additives is the Joint Expert Committee on Food Additives (JECFA) of the United Nations Food and Agriculture Organisation (FAO) and the World Health Organisation (WHO). This committee have introduced an Acceptable Daily Intake (ADI), which is an estimate of the amount of a food additive that can be consumed daily over a lifetime without presenting an appreciable risk to health. It’s normally expressed as milligrams of the substance per kilogram of body weight per day (8). The “without appreciable risk to health” part of the definition means that there is confidence that no harm will occur even after a lifetime of exposure to the additive in question.
If the idea of toxicity and food additives seems scary, it might be helpful to remember that lots of everyday things are also toxic in high doses, but it doesn’t mean we avoid them entirely. For example, too much sun or too much alcohol, and even too much water!
As well as having expert scientific committees in place to protect the consumer from too high a dosage of food additives, lots of foods will actually require a form of processing in order to make them safe for consumption.
For example, milk and other dairy products are pasteurised to kill off any harmful bacteria that might cause food poisoning.
How many times have you brought fresh fruit or vegetables only to forget about them for a week and then find them rotting at the back of your fridge? In an era where we want to promote sustainability and prevent food waste, processing foods to extend their shelf life should be seen as a good thing. Some may even argue that preserving foods (a form of processing) is one of the most environmentally responsible acts we can do to prevent food waste.
Products with a long shelf life are also essential in providing nutrition in scenarios such as emergency aid or for the military. Or an even more relevant example for most of us would be during the pandemic when a lot of us had to rely on the non perishable nature of processed foods to keep us going when we didn’t have as frequent access to food.
We shouldn’t underestimate the importance of being able to access foods that make our lives easier.
Whether or not they’re the most nutritious choice (this will depend on the specific food and context), there’s no denying that processed foods are convenient and last longer.
This is especially helpful for people struggling with food poverty, limited time, equipment, cooking skills, disabilities or chronic illness. For example, according to research commissioned by the Royal Voluntary Service and Yakult, nearly a million older people in the UK admit to relying on ready meals and convenience foods to keep themselves fed (9).
Relationship with Food
It’s common for us to think of foods in terms of ‘good versus bad’, but this thought process can be harmful to our relationship with food. This is because it puts food on a pedestal and can promote food anxiety, preoccupation and sometimes bingeing.
Avoiding processed foods entirely in an attempt to eat ‘clean’ is another way of categorising foods as ‘good’ or bad’ and will contribute to an unhealthy relationship with food. Like all foods, they’re fine in moderation and nutritious processed foods do exist! As outlined in this article, it’s just not true to say that processed foods are ‘bad’.
Why We Shouldn’t Fear Processed Foods
As with anything related to food and health, thinking with a black and white mindset will send you down a path of anxiety and distress over what you’re eating.
Processed foods aren’t going anywhere anytime soon and it’s practically impossible to avoid them in modern life. It’s important to remind yourself that these foods can be lifesavers for when you don’t have the time, energy or resources to cook from scratch and you shouldn’t feel guilty for including them in your diet.
- (no date) NHS choices. NHS. Available at: https://www.nhs.uk/live-well/eat-well/how-to-eat-a-balanced-diet/what-are-processed-foods/ (Accessed: December 23, 2022).
- Rauber, F. et al. (2018) “Ultra-processed food consumption and chronic non-communicable diseases-related dietary nutrient profile in the UK (2008–2014),” Nutrients, 10(5), p. 587. Available at: https://doi.org/10.3390/nu10050587.
- Rico-Campà, A. et al. (2019) “Association between consumption of ultra-processed foods and all cause mortality: Sun Prospective Cohort Study,” BMJ, p. l1949. Available at: https://doi.org/10.1136/bmj.l1949.
- Martínez Steele, E. et al. (2017) “The share of ultra-processed foods and the overall nutritional quality of diets in the US: Evidence from a nationally representative cross-sectional study,” Population Health Metrics, 15(1). Available at: https://doi.org/10.1186/s12963-017-0119-3.
- Howard, S., Adams, J. and White, M. (2012) “Nutritional content of supermarket ready meals and recipes by television chefs in the United Kingdom: Cross Sectional Study,” BMJ, 345(dec14 14). Available at: https://doi.org/10.1136/bmj.e7607.
- Olson, R. et al. (2021) “Food fortification: The advantages, disadvantages and lessons from sight and Life Programs,” Nutrients, 13(4), p. 1118. Available at: https://doi.org/10.3390/nu13041118.
- Rickman, J.C., Barrett, D.M. and Bruhn, C.M. (2007) “Nutritional comparison of fresh, frozen and canned fruits and vegetables. part 1. vitamins C and B and phenolic compounds,” Journal of the Science of Food and Agriculture, 87(6), pp. 930–944. Available at: https://doi.org/10.1002/jsfa.2825.
- Acceptable daily intake (no date) European Food Safety Authority. Available at: https://www.efsa.europa.eu/en/glossary/acceptable-daily-intake (Accessed: December 23, 2022).
- Every day thousands of older people skip meals or rely on ready meals (no date) Royal Voluntary Service. Available at: https://www.royalvoluntaryservice.org.uk/news/articles/every-day-thousands-of-older-people-skip-meals-or-rely-on-ready-meals/#:~:text=Almost%20a%20million%20(955%2C464)%20older,least%20three%20times%20a%20week (Accessed: December 23, 2022).