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A study published in the British Journal of Nutrition looks at ultraprocessed foods, nutrient content and package labelling.
Dr Nerys Astbury, Senior Fellow in Diet & Obesity, Nuffield Department of Primary Care Health Sciences, University of Oxford, said:
“Dicken and colleagues have explored and compared the front of pack traffic light labelling used on foods sold in the UK with the NOVA classification, which is a is able to group foods and drink according to the level of processing.
“The findings show that, perhaps unsurprisingly foods considered ultra-processed according to the NOVA classification tend to have an unhealthier profile on the front of pack labelling than minimally processed foods.
“There has been much attention given to the role of ultra-processed foods, which the authors say can have addictive-like properties and can drive excess consumption which can lead to weight gain, overweight, obesity.
“There are several reviews which show that diets high in ultra-processed foods are linked with higher risk of overweight and obesity, type 2 diabetes, cardiovascular disease and depression.
However, from these studies it has not been clear whether the effects can be attributed to the ultra-processing per se, or whether the effects of processing can be attributed to the nutrient profiles of the foods which tend to be ultra-processed i.e. ready-meals, pre-packaged cakes, crisps, biscuits, cookies, sweets chocolate.
“Consuming a diet containing lots of ultra-processed foods can also be a sign of other unhealthy dietary patterns and lifestyle behaviours. That’s because diets containing lots of ultra-processed foods also tend to have higher energy density (energy density is the energy (calories) in a given weight or volume of a food). The higher the energy density the more calories per gram or ml in the food. They also tend to be higher in saturated fat, salt and sugar, higher in processed meat and low in fruits and vegetables and fibre, and all of these patterns have already been shown to be associated with adverse health outcomes.
“In this study the authors demonstrate that ultra-processed foods are indeed more energy dense than foods with lower levels of processing and also tend to have more red/amber traffic lights for (and thus contain more) fat, saturated fat, sugar and salt. Whilst the front of pack traffic light system does present energy (calories) per 100g/100ml, this is not displayed in the red, amber green traffic light system. Only fat, saturated fat, sugar and salt content of food per 100g/ml are colour coded.
“When the authors looked at the foods classified as ultra-processed but had no red traffic lights on the front of pack label (so might be considered ‘healthy’) they had double the energy density compared with foods with a similar front of pack traffic light labels (all green) but classified as minimally processed.
“Not all of the foods examined fit the pattern – some ultra-processed foods had no red traffic lights, some had similar front of pack traffic light labels to minimally processed foods, and there were also some minimally processed foods that had red labels.
“Some caution should be exhibited when interpreting these findings. There are several limitations in using the NOVA classification system to UK dietary survey data from the National Diet and Nutrition Survey (NDNS), since the NDNS currently does not capture all of the detail required by NOVA. Therefore, the authors may under- or over-estimate the level of processing in some foods because of over-simplified interpretation of the NDNS food groupings.
“The traffic light system is based on amounts of nutrients in a food per 100g and does not reflect the portion of food which might typically be consumed.
“Whilst the authors suggest the findings have important implications for updating UK food and drink labelling, caution should be exhibited about recommending adding more labels on packaged food, which could be counterproductive and defeat the purpose of allowing consumers to make informed choices about foods. More labels on the front of pack could result in information overload (organic, red tractor, traffic light, nutrition claims etc), and conflicting messages.
“The recent report by The Scientific Advisory Committee on Nutrition (SACN) recommended that there is currently insufficient evidence to warrant inclusion of food processing into dietary guidelines, given that it is likely ultra-processing is already covered by existing dietary recommendations. The findings presented here suggest that the current traffic light system, which whilst not perfect, by and large captures food processing and overlaps with the processing categorisation of food using NOVA system.”
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:
“This study examines the degree of food processing with negative food labelling (e.g. high in fat, saturated fat, salt and sugar) and finds that ultraprocessed foods (UPF) contained more food energy/100 g than processed foods (medians 243 vs. 178). Salt content did not differ but many consumers still add salt during food preparation and at the table. There was no evidence to show the proportion of saturated fat was greater in the UPF foods compared to the processed food. Ultraprocessed food ingredients were high in calories (median 378 kcal/100g) due to their high fat content (median 19.1g). The energy content of minimally processed foods was low at 94 kcal/100g and contained very little fat. The main effect on energy content is driven by water (less water more calories) and fat content because fat provides 9 kcal/g compared to about 4 kcal for protein and carbohydrates (including sugars) and 4 kcal/g for fat. As a rule of thumb foods with an energy density over 200 kcal/100 g are more conducive to weight gain because it is difficult to much eat more than a kilogram of food daily.
“The limitation of the study is that it does not show the contribution made by the different processed food categories to key nutrients such as protein, calcium, iron, vitamins and fibre.
“This research shows diversity in the content of UPF which limits generalisations about their healthiness or otherwise. However, some UPF (e.g. crisps and similar snack foods) are very energy dense and consumers would be well advised to check the calorie content.”
Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading, said:
“This is an interesting comparison between different food classification systems: the conventional approach of using food composition, and the more novel – and still rather controversial – approach of using the degree of processing. Unsurprisingly, the authors found that many foods that are ultra-processed are high in fat, salt and sugar and would be considered to be ‘unhealthy’ under existing food classification models. However, the authors also highlight that not all ultra-processed foods have an ‘unhealthy’ composition and would indeed be classed as healthy.
“The study raises an important question about the focus on processing instead of food composition: many ultra-processed foods would be expected to be associated with poor health because of their food composition – and this is already shown in studies which distinguish between different types of ultra-processed foods. There is currently no evidence that suggests that processing has an adverse impact on health beyond food composition and possibly texture, as the latter can affect eating rate and result in over-consumption. Shifting the focus of public health messaging from a well-understood system of food composition to a rather ambiguous system of processing is likely to result in confusion but not a better diet.
“The study is well conducted as it looks into foods that are commonly consumed in the UK. There are obviously difficulties in assessing whether a food is really ultra-processed or not as the definition is ambiguous, but the authors use a process that is similar to the one used in other studies.”
‘Nutrients or processing? An analysis of food and drink items from the UK National Diet and Nutrition Survey based on nutrient content, the NOVA classification and front of package traffic light labelling’ by Samuel J. Dicken et al. was published in The British Journal of Nutrition at 00:01 UK time on Wednesday 14 February 2024.
DOI: 10.1017/S0007114524000096
Declared interests
Dr Nerys Astbury: “I am funded by NIHR, Diabetes UK and Diabetes Research & Wellness Foundation and supported by NIHR Applied Research Collaboration Oxford Thames Valley.”
Prof Tom Sanders: “Member of the Science Committee British Nutrition Foundation. Honorary Nutritional Director HEART UK.
Before my retirement from King’s College London in 2014, I acted as a consultant to many companies and organisations involved in the manufacture of what are now designated ultraprocessed foods.
I used to be a consultant to the Breakfast Cereals Advisory Board of the Food and Drink Federation.
I used to be a consultant for aspartame more than a decade ago.
When I was doing research at King’ College London, the following applied: Tom does not hold any grants or have any consultancies with companies involved in the production or marketing of sugar-sweetened drinks. In reference to previous funding to Tom’s institution: £4.5 million was donated to King’s College London by Tate & Lyle in 2006; this funding finished in 2011. This money was given to the College and was in recognition of the discovery of the artificial sweetener sucralose by Prof Hough at the Queen Elizabeth College (QEC), which merged with King’s College London. The Tate & Lyle grant paid for the Clinical Research Centre at St Thomas’ that is run by the Guy’s & St Thomas’ Trust, it was not used to fund research on sugar. Tate & Lyle sold their sugar interests to American Sugar so the brand Tate & Lyle still exists but it is no longer linked to the company Tate & Lyle PLC, which gave the money to King’s College London in 2006.”
Prof Gunter Kuhnle: “Employment: University of Reading (since 2010) and member of the USS pension scheme which has a portfolio that includes manufacturers of ultra-processed foods; Director of the University of Reading Chemical Analysis Facility with frequent interaction with instrument manufacturers.
Research funding: current funding from BBSRC TUKFS (Co-I, since 2020); past research funding from Mars, Inc (2014-2018); EU Horizon Programme (2012-2016).
Committee membership: Committee on Toxicity (COT) and various working groups, past member of the EFSA ANS panel and the American Academy of Nutrition and Dietetics working group on flavanols; Scientific advisory committee of the British Nutrition Foundation; Organising committee of the International Conference on Polyphenols and Health.
Scientific organisations: British Mass Spectrometry Society, Nutrition Society, Deutsche Gesellschaft für Epidemiologie and Deutsche Gesellschaft für Ernährung; Trinity Hall Alumni Organisation.
Registered Nutritionist.
Trustee of a Parent Teacher Association.
Family Vineyard.”