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Ultra-Processed Foods: The ‘Devil’ is in the Detail



We live in a world where time is a luxury and instant gratification reigns supreme. It may therefore be little wonder that ultra-processed foods (UPFs) have emerged in abundance on supermarket shelves and within our daily lives. Indeed, in the UK UPFs account for 60% of our food intake [1].


A recent series of sensationalist media reporting and influencer commentary has sought to demonise UPFs, recommending they should be avoided from the diet altogether. These ‘villains’ are being blamed for everything from obesity to chronic diseases. This surrounding narrative has stigmatised UPFs, resulting in their consumption being associated with shame and guilt.


But is it fair to paint all UPFs with the same brush?



What are Ultra-Processed Foods?

UPFs are highly modified foods, typically containing more than five ingredients such as fat, sugar, salt, preservatives, additives, emulsifiers, sweeteners and artificial flavourings [2]. These foods undergo multiple industrial processes, with the aim of enhancing taste, texture, appearance, stability and durability [2].


The term ‘ultra-processed food’ originated from a team of scientific researchers who created the NOVA classification to group foods according to their level of processing [2]:



So, should we cut out all UPFs from our diet?

It’s true that these foods are rarely nutritiously dense; however, there are many important factors and caveats we need to consider before taking a blanket approach of cutting out UPFs entirely:


1. UPFs can negatively affect our health, but we don’t fully understand how!

The scientific evidence around the potential health effects of UPFs has grown considerably in recent years, although it remains limited. Evidence does suggest that high consumption of UPFs is associated with increased risk of obesity, type 2 diabetes, cardiovascular disease, some cancers and overall mortality [3,4,5]. However, association doesn’t equal causality, so we do need more evidence specifically designed to assess whether UPFs are the direct cause of these outcomes.


The first such study from which we can derive causality (randomised control trial [RCT]) compared an ultra-processed diet with an unprocessed diet [6]. Meals within each diet were matched for calories, macronutrients and fibre, but participants could eat as much/little as they desired. When following the ultra-processed diet for two weeks, individuals ate around 500 calories (kcal) more each day, compared to the unprocessed diet (also followed for two weeks); this led to weight gain of 1 kilogram (kg) whilst the unprocessed diet led to weight loss [6]. Although we need much more evidence to draw definitive conclusions, what we have seen so far is indicative of UPFs having largely negative health implications.


What’s more uncertain though are the potential mechanisms underlying these probable harmful associations with higher UPF intake. This is a topic of much debate, with many hypotheses proposed [7]; often cited is enhanced sensory profile and palatability, driving overconsumption. Or is it poor nutritional quality? A lack of fibre, meaning we digest UPFs quickly and don’t feel full for long? The high fat, added sugar and salt content? Are there hormonal interactions at play? At this stage, we don’t definitively know. What is clear though, is that there are many areas to explore before justifying a complete avoidance of UPFs.


Do they increase appetite? Or does their palatability make them irresistible? Or is it their poor nutritional quality? We simply don’t know yet, why consuming UPFs leads to weight gain.



2. Not all UPFs are created equally

When we think of UPFs, images of packaged ready meals, chicken nuggets, crisps, biscuits and cake spring to mind. And certainly, many of these are high in calories, fat, salt and sugar, whilst lacking fibre and micronutrients. However, UPFs can vary significantly by both amount of processing and nutritional composition, yet they’re given the same label.


For example, did you know that packaged wholemeal bread, wholegrain cereal, baked beans and plant-based milks are also considered UPFs?

Such foods can provide important nutrients at affordable prices, contributing overall to a healthy, balanced diet. For example, many wholegrain cereals are high in fibre and fortified with B vitamins, vitamin D and iron, to name just a few…. The fortification process is a well-established tool for reducing nutrient deficiencies [8]. Avoiding these foods completely could increase risk of diseases associated with nutritional deficiencies, such as anaemia, hypothyroidism and osteoporosis [9]. We therefore cannot judge healthiness of a food purely by level of processing and instead must pay most attention to the overall nutritional composition.


3. A complex sounding ingredient doesn’t always mean it’s harmful

The advice currently being offered via the media regarding UPFs is that ‘if there’s a long list of ingredients, or ingredients you haven’t heard of or can’t pronounce, you should avoid it’. Whilst this guidance is generally valid and easily applied, we also need to be mindful that many food labels list the scientific names for important vitamins. Ever heard of Cobalamin, Ascorbic Acid, Ergocalciferol-D3 or Tocopherol? Whilst these sound like chemicals we should avoid, they’re better known as Vitamins B12, C, D and E… [9] Of course, in this format it is difficult to distinguish between these and the potentially harmful ingredients, so it is sensible to remain sceptical and, where possible, opt for whole foods to meet our vitamin and mineral needs.


4. Food privilege

Whilst cooking with mainly unprocessed foods would be optimal, this requires knowledge, skills, equipment and time. There’s no denying that these are privileges that not everyone has. Unprocessed foods are also more expensive [10] and don’t last long. With the UK cost-of-living on the rise and low-income families struggling with food poverty, UPFs are often relied upon for their affordability, convenience and durability [11].





It's all about balance

Based on the existing evidence, limiting consumption of UPFs is a sensible approach: a nourishing diet is essential for giving your body what it needs and overall, UPFs are not very nourishing [12]. But there is no need to completely avoid UPFs and even within UPFs, we can make healthier choices.


When consuming UPFs, we should be careful that they are not displacing healthier food groups from the diet, particularly as evidence of the negative health effects of low consumption of foods including fruit, vegetables and wholegrains is well established [13]. In essence, absence of certain foods in the diet is just as critical as presence of certain foods.


As with most things in life, a balanced approach to diet is key. A good way to achieve this could be an 80:20 mindset. Are you consuming non-UPFs most of the time? If so, there should be minimal apprehension around occasional intake of UPFs.


The bigger concern is for individuals who aren’t able to afford or access more nutritious food, and therefore solely consume UPFs. This is where the major health implications lie, and where more needs to be done to tackle food and health inequalities and poverty.



If you think your diet would benefit from a reduction in UPF consumption, here are a few helpful tips:


  • Progress, not perfection: Instead of cutting out UPFs completely, try to increase your intake of nutrient-rich foods like fruit, vegetables, pulses and wholegrains. If you’re using a ready-made pasta sauce, why not add more vegetables (fresh or frozen) to boost nutritional quality? How about replacing one sugary drink with water instead?

  • Batch cook meals: set aside some time each week to batch cook nutritious meals for the week ahead or for storing in the freezer. This can help avoid reliance on UPFs when time is short.

  • Get to know food labels: reading food labels can enable healthier choices. Opt for foods lower in saturated fat, sugar and salt, and higher in fibre, vitamins and minerals.

  • Portion control: Be mindful of portion sizes and stick to recommended portion sizes. Eat slowly and mindfully and listen to the body’s hunger cues to avoid overconsumption.

  • Snack smart: Choose snacks that are not just satisfying but nourishing and satiating too! To achieve this, bring in minimally processed foods and combine food types (e.g. protein with grains or fruit and veg). For example, carrot sticks and hummus or sliced apple and peanut butter.

  • Don’t fear processing: You don’t need to cook everything from scratch to achieve a healthy diet; processing provides many great benefits including safety, convenience and durability. We should limit consumption of UPFs, but the ‘processed foods’ category shouldn’t be feared.



References


[1] 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), pp. 587. doi:10.3390/nu10050587.


[2] Monteiro, C.A. et al. (2017) The UN Decade of Nutrition, the NOVA food classification and the trouble with ultra-processing, Public Health Nutrition, 21(1), pp. 5-17. doi:10.1017/S1368980017000234.


[3] Pagliai, G. et al. (2021) Consumption of ultra-processed foods and health status: a systematic review and meta-analysis, British Journal of Nutrition, 125(3), pp. 308-318. doi:0.1017/S0007114520002688.


[4] Fiolet, T. et al. (2018) Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort, British Medical Journal, 360, pp. k322. doi:10.1136/bmj.k322.


[5] Delpino, F.M. et al. (2021) Ultra-processed food and risk of type 2 diabetes: A systematic review and meta-analysis of longitudinal studies, International Journal of Epidemiology, 51(4), pp. 1120–1141. doi:10.1093/ije/dyab247.


[6] Hall, K.D. et al. (2019) Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake, Cell Metabolism, 30(1), pp. 67-77.e3. doi:10.1016/j.cmet.2019.05.008.


[7] Elizabeth, L. et al. (2020) Ultra-Processed Foods and Health Outcomes: A Narrative Review, Nutrients, 12(7), pp. 1955. doi:10.3390/nu12071955.


[8] Olson, R. et al. (2021) Food Fortification: The Advantages, Disadvantages and Lessons from Sight and Life Programs, Nutrients, 13(8), pp. 1118. doi:10.3390/nu13041118.


[9] Berger, M. et al. (2022) ESPEN micronutrient guideline, Clinical Nutrition, 41(6), pp. 1357-1424. doi:10.1016/j.clnu.2022.02.015.


[10] Food Foundation (2022). The Broken Plate 2022. Available at: https://foodfoundation.org.uk/publication/broken-plate-2022 (Accessed: 26 May, 2023).


[11] Food Foundation (2023). From purse to plate: implications of the cost of living crisis on health. Available at: https://foodfoundation.org.uk/sites/default/files/2023-03/TFF_Cost%20of%20living%20briefing.pdf(Accessed: 26 May, 2023).


[12] Martini, D. et al. (2021) Ultra-Processed Foods and Nutritional Dietary Profile: A Meta-Analysis of Nationally Representative Samples, Nutrients, 13(10), pp. 3390. doi:10.3390/nu13103390.


[13] Afshin, A. et al. (2019) Health effects of dietary risks in 195 countries, 1990–2017: A systematic analysis for the global burden of disease study 2017, The Lancet, 393(10184), pp. 1958–1972. doi:10.1016/S0140-6736(19)30041-8.




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