By researchers from the University of Cambridge MRC Epidemiology Unit – Yanaina Chavez-Ugalde, Andrea Smith, Luiza I.C. Ricardo and Esther van Sluijs
Ultra-processed food, or UPF in short, is a hot topic in public health research. Here we will explain some of the controversy around UPF and why we believe research with youth is essential.
So, what is all the fuss about ultra-processed foods?
Over the past fifty years, the food industry has developed extensive industrial food manufacturing techniques. These techniques have changed how foods are promoted, consumed, their taste and their cost when compared to minimally processed foods. Whilst some processing of food can be beneficial to health (e.g., increased safety, shelf-life), some attributes of ultra-processing (e.g., emulsifiers, non-caloric sweeteners, hydrogenated oils) have been associated with ill-health through physiologic and behavioural mechanisms leading to over-consumption, and increased risk of cardiovascular disease and obesity [1]. There are growing concerns around the health risks of food processing, which are independent to considerations around diet quality and a food’s nutritional composition.
Recently, UPFs have garnered a lot of attention. This term has become a buzzword and it is hard to define, but without getting lost on details, it classifies food based on how much it has been processed before it is consumed. The NOVA food classification system is a widely used tool to classify foods in terms of their level of processing [2]. It helps researchers, policymakers, and health professionals better understand the role of food processing in diets and its potential health implications. There are four groups according to NOVA:
1. Unprocessed or minimally processed foods, such as washed, frozen, chopped, dried or fermented whole foods;
2. Processed culinary ingredients, such as salt, sugar, butter, and cooking oils;
3. Processed foods which combine groups 1 and 2 with the purpose of preservation or increasing taste; and
4. Ultra-processed foods which are “industrial formulations” [2] manufactured by taking apart foods into their component parts, altering them and recombining them with a range of additives and little, if any, whole foods.
Examples of UPFs include soft drinks and energy drinks (normal and diet versions which use non-nutritive sweeteners), crisps, ice-cream, fruit yoghurts, meat replacement burgers, instant soups and sweetened breakfast cereals.
In summary, the NOVA food classification system is a widely used tool to capture and better understand shifts in consumption patterns of UPF and it enables evaluating the degree and purpose of food processing, separate from a foods nutrient content.
The largest young generation in history – why youth matters
Adolescence is an exciting developmental phase in a young person’s life. This age often is characterised by a striking change in a young person’s independence to make their own decisions and take on more responsibilities. This newfound independence is a crucial aspect of their development as they transition from childhood to adulthood. In this transformative phase of life, this independence to make own life choices can cover areas like new friend groups, hobbies, career choices as well as food. The WHO defines adolescence to cover ages between 10–19 and ‘youth’ as people between the ages of 10–24 [3, 4], in recognition that growing into adulthood is not solely determined by physical development but also involves these important social and psychological changes. Youth currently make up a quarter of the world’s population (1.8 billion are aged 10–24 years), the largest young generation in history. This is important, because this period can be both exhilarating and challenging as they learn to balance their independence with externals stresses, responsibilities and try to navigate the guidance and support provided by families, friends, communities and increasingly the digital world too. Adolescents’ experiences, behaviours and habits greatly shape and influence their future health, (e.g., metabolic health, risk for cancers and cardiovascular health) as well as their wellbeing [5]. Food habits created during adolescence impact health throughout the life course, making it a critical stage of human development.
Ultra-processed foods and adolescent health
There is growing concern about high levels of UPF consumption. In UK adults, 57% of daily energy intake derive from UPF, with an even higher proportion seen in adolescents (66%)[6]. A lot of foods classified as UPF are often deemed ‘junk food’ – food with low nutrient content but high in saturated fats, free sugar or salt, for example, crisps or supermarket biscuits. High-levels of regular consumption of these foods elevate the risk of obesity and serious chronic diseases such as type 2 diabetes across the life course [7]. However, it is important to remember that UPFs also includes foods that are affordable, accessible and nutritious (e.g., supermarket bread made with wholegrain fortified flour).
UPFs increasingly define adolescents’ consumption patterns, and adolescents are the age group with highest consumption of UPFs [8–11]. There is an important relationship between socio-economic background and UPF consumption. In the UK, adolescents from higher socio-economic backgrounds consume lower overall levels of UPF (62% of daily energy intake) compared to those from lower socio-economic backgrounds (69% of total energy intake). However, adolescents from lower socio-economic backgrounds are more likely to consume UPF subtypes that are perceived as less healthy, and these dietary disparities during adolescence are worrisome [9, 12, 13]. Addressing the implications of UPF consumption among adolescents, particularly in the context of socio-economic disparities, is crucial for improving public health and reducing health inequalities in the UK. However, providing a ‘one-size-fits-all’ recommendation to reduce UPF without understanding how, when and why adolescents consume them at best would be ineffective, and at worst may backfire or even shame young people about their own or food choices or their familial food culture.
Either way, changing over half of all food consumed in the UK is not going to be an easy endeavour, but, addressing this in adolescent years, when habits are still being formed, provides a great opportunity to protect the next generation from the potential risk that a high consumption of UPF entails. Now is the time to invite young people to the table for policymakers, healthcare professionals, and educators to consider implementing policies that discourage the consumption of unhealthy UPF, and make non-UPF more accessible as a way to improve public health and reducing health inequalities early in life in the UK.
References
- Astrup, A. and C.A. Monteiro, Does the concept of “ultra-processed foods” help inform dietary guidelines, beyond conventional classification systems? Debate consensus. The American Journal of Clinical Nutrition, 2022.
- Monteiro, C.A., Cannon, G., Lawrence, M., Costa Louzada, M.L. and Pereira Machado, P. Ultra-processed foods, diet quality, and health using the NOVA classification system. Rome, FAO, 2019.
- WHO, The second decade: improving adolescent health and development. 2001, World Health Organisation: Geneva.
- United Nations. Definition of Youth. 2013 September 2023; Available from: https://www.un.org/esa/socdev/documents/youth/fact-sheets/youth-definition.pdf.
- Neufeld, L.M.P., et al., Food choice in transition: adolescent autonomy, agency, and the food environment. The Lancet, 2022. 399(10320): p. 185-197.
- Chavez-Ugalde, Y., et al., Manuscript title: Ultra-processed food consumption in UK adolescents: distribution, trends, and sociodemographic correlates using the National Diet and Nutrition Survey 2008/09 to 2018/19. medRxiv, 2023: p. 2023.06.05.23290977.
- Bibbins-Domingo, K., et al. Adolescent overweight and future adult coronary heart disease. The New England journal of medicine, 2007. 357(23): p. 2371-9.
- Cediel, G., et al. Ultra-processed foods and added sugars in the Chilean diet (2010). Public Health Nutr, 2018. 21(1): p. 125-133.
- Khandpur, N., et al. Sociodemographic factors associated with the consumption of ultra-processed foods in Colombia. Rev Saude Publica, 2020. 54: p. 19.
- Louzada, M.L., et al. Consumption of ultra-processed foods and obesity in Brazilian adolescents and adults. Preventive medicine, 2015. 81: p. 9-15.
- Rauber, F., et al. Ultra-processed foods and excessive free sugar intake in the UK: a nationally representative cross-sectional study. BMJ Open, 2019. 9(10): p. e027546.
- Shim, J.S., et al. Socioeconomic Characteristics and Trends in the Consumption of Ultra-Processed Foods in Korea from 2010 to 2018. Nutrients, 2021. 13(4).
- Parnham, J.C., et al. The Ultra-Processed Food Content of School Meals and Packed Lunches in the United Kingdom. Nutrients, 2022. 14(14).