What exactly is ultra-processed food and how bad is it for me?

The Quick Takeaway

  1. Ultra-processed food (UPF) is a term used to describe food that is energy dense, high in sugar, salt and unhealthy fats, and low in fibre.  It is also used to describe foods that have been broken down, and then processed, to manufacture a finished food item with many added ingredients.
  2. The food classification system most commonly used in research is the NOVA system which divides food into four categories namely unprocessed/minimally processed food, processed culinary ingredients, processed food and ultra-processed food.
  3. UPF typically has a number of ingredients including artificial flavours, stabilisers and enhancers that are not normally used in the home kitchen.
  4. In some developed countries including the UK, USA and Canada, UPF makes up more than 50% of the diet of the population. 
  5. It is difficult to research the impact of diet on health because it is unethical to ask participants to eat an unhealthy diet for a long period of time.  A lot of the research comes from either observational studies, where the diet of the population is associated with the health of the population, and prospective studies where participants with a known dietary pattern are followed up over a number of years and the health outcomes recorded, but there are also a small number of short term randomised controlled trials (RCTs).
  6. All the evidence points to UPF consumption having an adverse effect on body size and health outcomes. High UPF consumption is linked to high body mass index (BMI), to all-cause mortality and to a wide range of diseases including cardiovascular disease, type 2 diabetes, accelerated ageing and common mental health disorders.
  7. It is not easy to be sure what it is about UPF that leads to the adverse health effects.  It is clear that the nutrient composition is important.  UPF is high in sugar, fat and salt and low in fibre, all of which are known to have adverse health impacts.  Moreover, eating a lot of UPF means that individuals do not have the appetite to eat healthy foods including fruit and vegetables.
  8. Nevertheless, there seems to be something that is intrinsic to the UPF itself which is having an additional adverse health impact.  This may be due to the food structure, the re-processing of the food items, the industrial ingredients, the packaging or a combination of these factors.
  9. Studies which look at different types of UPF have found that some types of UPF consumption are strongly associated with adverse health outcomes whereas other types of UPF seem to be benign. Processed meats and sweetened beverages are reported to have the greatest negative health impact.
  10. Some researchers believe that the NOVA classification system, with one category for UPF is too broad, and that a more sophisticated classification system is required to reflect the nutrient quality, the many different types of processing and the number and type of added ingredients of a food.
  11. UPF consumption varies across the population.  Research into different groups does not give completely consistent results, but studies suggest that UPF consumption is higher in young people, males, in urban areas and in people of lower socioeconomic status.  

The Full Deal

The term ultra-processed food (UPF) is used to refer to food that is energy dense and high in sugar, salt and unhealthy fats, and low in fibre.  It is also used to describe foods that have been broken down and then processed to manufacture a finished food item with many added ingredients.

Most research on UPF relies on the NOVA system to describe different types of food.

The NOVA Classification System

The NOVA system, (first proposed in 2009) divides all foods into four categories according to the degree of processing (Monteiro et al, 2019).  The four categories are:

  • Nova Group 1 – Unprocessed foods and minimally processed food
  • Nova Group 2 – Processed culinary ingredients, mainly used to cook items from Nova Group 1
  • Nova Group 3 – These are processed foods which result from combining foods in the first two groups
  • Nova Group 4 – Ultra processed foods which are formed from a series of processing steps, and importantly, foods are often broken down into separate components for further processing before being combined into a finished food item.

The fourth category, ultra-processed, is described as food items that include ingredients that are not normally found in home kitchens such as hydrogenated oils and hydrogenated proteins and additives such as flavour enhancers, emulsifiers, artificial sweeteners and bulking agents.  If one of more of these “industrial” components, not normally used by home cooks is on the ingredient list then the food item is ultra-processed.  Using this definition more than half of the typical diet in the UK, USA and Canada is made up of ultra-processed foods and the proportion of ultra-processed foods in the diet is growing.

The NOVA system is descriptive which means that an individual food item can move through the classification groups depending on how it is presented.  For example, plain cut oats are minimally processed (Group 1) but they become processed (Group 3) if they are sold with salt or sugar (items from Group 2).  They become ultra processed (Group 4) if flavourings or colourings are added.

Are Ultra-Processed Foods Unhealthy?

There is a considerable body of evidence linking UPF with poor health outcomes.  Most of the studies in this area come from one of two types of study, observational (or cross-sectional) and prospective cohort.

Observational Studies

Observational, or cross-sectional studies rely on collecting data on diet in a large group of participants and looking for associations with other factors such as being overweight or obese.  An example of this type of study is the analysis of data from the US based National Health and Nutrition Examination Survey (NHNES).  This is a regular survey designed to be representative of the US population and data are collected on diet over a 24hour period and on participant demographics.  Juul et al (2022) published findings based on 40,397 adults over the period 2002-2018.  Diets were analysed according to the NOVA system.  Over the study period the consumption of UPF increased from 53.5% of total calories to 57% of total calories.  In older adults, consumption of UPF was more than 60%.  The consumption of UPF was lower in people of Hispanic origin and in college graduates. Over the study period there was an increase in the consumption of ready to heat and ready to eat meals.  Over the same time period in the US there was an increase in the population in Body Mass Index[1] (BMI) and in the incidence of obesity, despite an improvement in the macronutrient content of the diet.  This type of study can show a correlation between increased consumption of UPFs and an increase in obesity, but is not able to show that one causes the other.  The value of observational studies is limited because they are dependent on participants accurately recalling what they have eaten and many researchers in this field believe that the consumption of UPF is under reported.

Rauber et al (2020) conducted a similar study of UPF consumption in the UK.  There were 6,143 participants in the study and diet was classified according to the NOVA system.  In this study 54.3% of calories consumed came from UPF, 30.7% from unprocessed or minimally processed food, 10.1% from processed food and 4.9% from culinary ingredients.  There was a correlation between UPF consumption and obesity, BMI and waist circumference.

Observational studies can also be conducted across countries.  Monteiro et al (2017) looked at the relationship between UPF consumption and obesity in different European countries.  They considered 19 European countries and on average the UPF consumption was 26.4% with Portugal the lowest at 10.2% and the UK the highest at 50.4%.  They found a correlation between UPF consumption and obesity in adults which persisted after adjusting for national income, physical activity and smoking.   The also found a strong correlation between the availability of UPF in the country and obesity.

Other observational studies have looked at specific health effects of UPF consumption.  Esposito et al. (2024) examined the relationship between UPF consumption and accelerated aging.  They assessed biological aging through blood biomarkers.  The study was carried out in Italy, with 22,495 participants and food was classified using the NOVA system.  Diet quality was measured by the Mediterranean Diet Score.  A higher intake of UPF was associated with accelerated aging and a bigger difference between biological and chronological age.  The authors commented that the difference in age could not be fully explained by the nutritional content of the foods consumed suggesting that the observed effect is in part due to the processing of the food.

Prospective Studies

In the prospective cohort study type the researchers follow a group of participants for whom there is data on diet and they record the mortality and morbidity in the cohort over time. A representative example of this kind of study is the large prospective study carried out in France which followed more than 44,000 participants for on average 7.1 years (Schnabel et al. 2019).  UPF made up on average 29.1% of the energy intake for the participants.  This is low compared to the amount of UPF in the diet in the UK, USA and Canada.  Nevertheless, the authors found a correlation between the amount of UPF consumed and all-cause mortality. 

More than thirty years of follow-up from a US based cohort study of 114,064 participants (all healthcare professionals) with food frequency questionnaires administered every four years and with no cancer, cardiovascular disease or type 2 diabetes at baseline was reported by Fang et al. (2024).  Consumption of UPF was associated with higher all-cause mortality, but no association was observed for cancer and cardiovascular disease mortality.  The association between all-cause mortality and the consumption of UPF was weakened when the researchers controlled for diet quality and smoking. The authors concluded that overall diet quality had the biggest impact on health and that consuming ultra processed food had a small additional effect.

Meta-analyses

Meta-analyses are a useful way of combining data from studies looking at the association between UPF consumption and health outcomes.  Pagliai et al. (2021) analysed data from 23 studies; 10 cross sectional and 13 prospective cohort studies.  In the observational studies the authors found that study participants eating a high UPF diet compared to those eating a low UPF diet had an increased risk of overweight, obesity, waist circumference and metabolic syndrome and a corresponding decrease in HDL cholesterol. The same pattern of results was found in the prospective cohort studies.  They found an increase in all-cause mortality, cardiovascular disease, cerebrovascular disease and depression in those with the higher consumption of UPF.  The authors added a caveat that the conclusions for the prospective cohort studies were based on a small number of studies and study participants. 

Other investigators have reported similar findings.  Askari et al. (2020) pooled data from 14 studies looking at UPF consumption and overweight/obesity.  Like Pagliai et al. (2021) they found a significant association between UPF consumption and overweight/obesity.  

Lane et al. (2024) conducted a review of meta-analyses.  They identified 45 analyses from 14 studies.  Across all these studies close to one million participants were involved.   Lane et al. found associations between the consumption of UPF and 32 health parameters including mortality, cancer, mental health, respiratory disease, cardiovascular disease, gastro-intestinal disease and metabolic health.  The strongest association was for cardiovascular disease mortality, type 2 diabetes and common mental health disorders.

It is possible that the sometimes inconsistent health outcomes reported in these studies may be influenced by the broad description of UPF that they use.  There are data that indicate that various types of UPF influence health outcomes in different ways.  This is considered in more detail below in the section on “Are Ultra-Processed Food Equally Unhealthy”.

Controlled Trials

The gold standard type of investigation is the randomised clinical trial (RCT).  Conducting RCTs of different diet types is problematic; it is difficult to ensure that participants will follow a prescribed diet for long periods of time and there are serious ethical considerations in asking people to eat a diet which is known to have poor health outcomes.  There are, however, a small number of RCTs that have compared a healthy diet and a diet high in UPF for short periods of time.

The RCT by Hall et al. (2019) which examines the effect of consuming UPFs on body weight is highly cited in the literature.  In Hall et al.’s study, twenty participants were randomised to receive one of two diets, a healthy diet and a diet high in UPF (as defined by the NOVA system).  Importantly, the two diets were matched in terms of calorie content and macronutrients.  The participants were able to eat as much as they wanted of their allocated diet.  After two weeks the participants were switched to the other diet.  In the trial, calorie intake was significantly higher when the participants ate the UPF diet, meaning they ate more.  Moreover, when participants were on the UPF diet their calorific intake increased over the two-week period.  This did not happen on the healthy diet.   The study also found that participants on the UPF diet, ate faster. Unsurprisingly participants gained weight on the UPF diet and lost weight on the healthy diet (0.9Kg). It is interesting to note that the healthy diet was costed at 50% more than the UPF diet, a point that we will return to later when the social effects of UPF are considered.

A similar study was conducted in Japan (Hamono et al. 2024) albeit with a slightly different focus.  Nine overweight/obese males were admitted to an in-patient hospital ward for two periods of a week with a two-week break between the two admissions.  Patients received a no UPF diet for a week and a diet that was high in UPF, as classified by the NOVA system, for a week.  The two diets were matched in terms of macro-nutrients and energy and the participants could eat as much as they wanted on each diet. The study found that on the UPF diet participants put on 1.1Kg and consumed 813.5 calories per day more than on the non-UPF diet.  The body weight changes correlated with the differences in energy intake.  In this study energy intake on the UPF diet was increased at lunch and dinner, but not at other times.  The increased energy intake came from increased consumption of carbohydrates and fats.  Fibre intake was lower on the UPF diet.

The overwhelming evidence from all these studies is a link between the consumption of UPFs and adverse health outcomes.  The effect of UPF consumption seems to be more than simply displacing healthy foods from the diet.  Most studies in this field adjust for diet quality but the adverse effect of UPF on health remains suggesting strongly that UPF consumption has a direct effect on health outcomes.

Why are Ultra-Processed Foods Unhealthy

The nutritional make-up of UPF makes its consumption an unhealthy choice. UPF is high in sugars, unhealthy fats and salt and UPF is low in fibre, a combination of macro-nutrients that is known to be associated with adverse health outcomes.

Rauber et al (2018) looked at the impact of UPFs on the intake of macronutrients.  In this UK based study there were 4,738 adult participants and 4,636 children.  Food consumption was classified according to the NOVA system. In this cohort 56.8% of calories consumed were from UPFs, the range being 34.9% to 78.0%.  In the study increased UPF consumption was associated with increases in the consumption of carbohydrates, free sugars, total fats, saturated fats and sodium.  Increased UPF consumption was also associated with decreases in the intake of protein, fibre and potassium. 

The poor nutritional content of much UPF is not disputed, but when investigators control their results for diet quality the UPF is seen to have adverse health outcomes above that expected from the nutrient quality. The two RCTs described above where diet was matched in terms of macronutrients showed an adverse health impact of a UPF diet.  Similarly in the observational and prospective cohort studies, where investigators have controlled their results for diet quality, adverse health outcomes have been attributed to the UPF consumption itself.  

This additional adverse health impact of UPF consumption was seen in a study that investigated the relationship between food processing and diabetes (Dicken et al. 2024).  This was a prospective cohort analysis and part of the European Prospective Investigation into Cancer and Nutrition (EPIC) study.  Diet was assessed at baseline and classified according to the NOVA system.  311,892 participants took part and were followed up for 10.9 years.  Over that time there were 14,236 cases of type 2 diabetes identified.  Participants in the highest UPF consumption quartile had a poor diet quality as measured by adherence to the Eatwell Plate Guide and the Mediterranean diet and a higher intake of total energy from total fat, saturated fat, carbohydrate and sugar.  Nevertheless, the association between UPF consumption and type 2 diabetes remained after controlling for diet quality.  The authors of the study suggest that UPF consumption acts adversely on health through poor nutrient intake and another factor related to the processing itself.

The team behind the large cohort study in France (Schnabel et al. 2019), state that their results indicated that there was something beyond the sugars, salt and unhealthy fats in the UPF that was causing the increased mortality and hypothesised that ingredients used in the processing itself such as additives, contaminants and packaging were contributing to the all-cause mortality.

Rauber et al.  (2020) who reported on the cohort study in the UK said that their results support the hypothesis that eating UPF promotes over eating, but they were unable to identify a mechanism.  They suggested that the structure of UPF and the presence of additives may have an adverse effect on the gut microbiome that promotes inflammatory disease.  They also suggested that the plastics in the packaging of UPF may contribute to its adverse effects. 

In the RCT by Hamono et al. (2024) described above, the number of chews the participants made was measured.  The number of chews per calorie consumed was lower on the UPF diet and the eating rate faster.  This result is not surprising as minimally processed food contains more fibre and as a consequence requires more chewing. The authors comment that human satiety is linked to the volume of food consumed rather than the calorie content.  Calorie dense UPFs can be consumed quickly before satiety mechanisms are triggered.  The authors also argue that the intense flavourings of UPFs may override satiety mechanisms.

Mendoza et al (2024) analysed food frequency questionnaires from three large surveys with a total of 206,957 participants where diet was assessed every two to four years. They found that total UPF consumption was correlated with cardiovascular disease and coronary heart disease.  They argue that the risk factors from the nutrient themselves are further increased by packaging materials, chemicals produced during the preparation of the foods and the thickeners and emulsifiers used in the processing.  They caution against the broad categorisation of UPFs commenting that some UPFs which are high in fibre, minerals and whole grains have nutrients which are known to be cardioprotective.

Sadler et al. (2021) in a review of studies examining food processing and health outcomes consider why processing may be harmful for health.  They comment that extensive processing may break down the structure of the food so that starch and sugar become more accessible to the digestive system leading to blood sugar spikes which are believed to have a negative metabolic impact.

Dicken and Baterrham (2021) reviewed the data on the relationship between health, UPF and diet quality to shed light on the question of whether the poor health outcomes linked to UPFs are due to nutrient content or food processing.  They found that UPFs were associated with poor health outcomes, and with weight gain, overweight and obesity, after controlling the data for diet quality.  The poor health outcomes were obesity related and included cardiovascular disease, type 2 diabetes, depression and all-cause mortality. Like other investigators in this field, they point out that UPFs are poor nutritionally with high energy density, low nutrient content and high in fat, sugar and salt.  They also highlight that the palatability of UPFs increases the rate at which they can be eaten leading to a tendency to overconsumption.  They postulate that the ultra-processing itself may be an additional factor contributing to the adverse health impact.  The texture of the foods increases the consumption rate and satiety is reduced because the foods are consumed quickly.  These factors together can lead to hyperglycaemia. Other mechanisms mentioned to explain the adverse health effects of UPFs include additives adversely influencing the gut microbiome and promoting inflammation.  The authors make the point that we need to understand the mechanisms by which UPFs adversely impact health so that appropriate guidance can be given on either avoidance or reformulation.

The role of emulsifiers, an ingredient type often found in UPF, in the development of type 2 diabetes was studied prospectively in a cohort of 104,139 adults in France (Salame et al. 2024).  Participants kept a dietary record for three 24 hour periods every six weeks and were followed up for on average 6.8 years.  The researchers found a direct association between the development of type 2 diabetes and exposure to food additive emulsifiers.  Researchers from the same centre (Sellem et al. 2023) have conducted a similar study investigating a link between UPF and cardiovascular disease.  They found a relationship between the consumption of emulsifiers and the development of disease but the emulsifiers driving the association were not the same as those identified for the development of diabetes.  The link between the development of disease and the consumption of emulsifiers, in both studies, persisted after controlling for overall UPF intake and for the intake of artificial sweeteners.

The evidence therefore indicates that the adverse impact of UPF consumption on health comes from the macronutrient composition and additional factors associated with the processing that remain poorly understood.  It seems that the food composition and structure, the added ingredients and the packaging may all play a role.

Are Ultra-Processed Foods Equally Unhealthy

Some of the studies of UPF divide UPF into different types of food.  These studies suggest that not all types of UPF have the same health outcomes although the results across studies are not always consistent.

The large US based cohort study described above (Fang et al. 2024) found that the relationship between UPF and all-cause mortality was stronger for some categories of UPF than others.  The strongest association was seen between mortality and the consumption of meat/poultry/sea food based ready to eat products.  Also driving the association between UPF consumption and all-cause mortality was the consumption of sugar and artificially sweetened beverages, dairy based desserts, and ultra-processed breakfast foods. 

The study that examined the relationship between the development of type 2 diabetes and the consumption of UPF (Dicken et al. 2024) found that although UPF consumption seemed to be related to the development of type 2 diabetes not all UPFs behaved in the same way.  They found that consumption of savoury snacks, animal-based products, ready to heat/eat dishes and sweetened drinks were associated with a higher incidence of type 2 diabetes whereas bread, biscuits, breakfast cereals, sweets and deserts, and plant based alternative foods were associated with a lower incidence of type 2 diabetes.  

In Mendoza at al.’s prospective study (2024) the incidence of cardiovascular disease, coronary heart disease and stroke amongst the participants was examined in relation to the consumption of different types of UPFs. The authors found that total UPF consumption was correlated with cardiovascular disease and coronary heart disease, but that the strongest relationship between cardiovascular disease and UPF consumption was with the consumption of sugar sweetened and artificially sweetened drinks and with processed meats.  In contrast, they found that the consumption of bread, cold cereals, yogurt, dairy desserts and savoury snacks was associated with a reduced risk of cardiovascular disease.  They comment that the UPF groups most associated with increased rates of cardiovascular disease and coronary heart disease are energy dense and high in added sugars, salts, fats and sodium which are all known cardiovascular disease risk factors. 

These studies indicate that a single category of UPF may be too broad to properly understand the impact that the consumption of this type of food has on health outcomes and that other ways of classifying foods may be more useful.

Classification of UPFs

Most research into the health outcomes of UPFs use the NOVA classification, but alternatives to the NOVA system have been suggested.

Petres et al. (2021) argue that the NOVA system is based more on the number of ingredients than the degree of processing of the food.  The authors also question the implication of the NOVA system that food made in the home kitchen is always good whereas food made in a factory is bad. Instead, the authors argue that the healthiness of food should be based on the underlying nutritional value of the ingredients. 

In a review of food classification systems by Sadler et al. (2021) it is acknowledged that NOVA is the basis of the most publications and that it has been widely used to study the relationships between industrial food products and the nutritional value of the food and also the relationship between industrial food products and health or the development of chronic diseases.  The reviewers agree with Petres et al. that the degree of processing is not necessarily related to the nutritional value of the food.  Classification systems like NOVA are pragmatic and are not based in theory.  They say that “There is no clear agreement on what features make a food more or less processed”.

Support for the difficulties in classifying foods comes from a French study where food and nutrition specialists were asked to classify foods according to the NOVA system (Braesco et al. 2022).  The foods were all commonly consumed in France and a quarter of them were placed in different NOVA categories by the evaluators. The researchers suggest that it may be helpful to separate foods that have undergone many processing steps from foods that have many additives to try and understand better what is influencing adverse health outcomes.

To solve this problem Mozaffarian et al. (2021) have proposed an alternative food profiling system which they call the Food Compass.  They scored 54 characteristics across nine domains covering the macro and micro ingredients, nutritional value, types of ingredients and processing characteristics to give a score from one to one hundred with 100 being the most healthy.  The researchers argue that Food Compass gives much better discrimination than the NOVA classification.   Barrett et al. (2024) published an updated version of the Food Compass.  In this second version positive points were awarded for non-processed items as well as negative points for processing. The researchers used Food Compass Version 2 to analyse the diet of 47,099 US adults and they found a good correlation between the Food Compass score and other validated measures of a healthy diet.  They also found that the Food Compass score correlated with BMI and a number of metabolic markers, as well as all cause mortality, cardiovascular disease, cancer and lung disease.

Ravandi et al (2025) suggested a classification system for processed foods that allows a more nuanced scoring and bases the score itself on biological mechanisms.  The scale, FPro, runs from zero to one where zero is the least processed, and one is the most processed. 

It is possible that, in the future, the use of these more sophisticated food classification systems could help unravel the relationship between food processing and health outcomes.

Demographic Factors

It appears that the consumption of UPF is not equally distributed across the population and this has been investigated in several countries.

In France, Calixto Andrade et al (2021) found in a cross-sectional study of 2,642 adults that 31.1% of energy intake came from UPFs with ready to eat meals and confectionary being the largest contributors. In terms of total amount of food eaten in grams the proportion of UPF fell to 24.1%.  This reflects the energy density of UPF.  UPF consumption was higher in younger people and people living in towns and lower in people with the lowest educational achievements and people who were retired. This study excluded adolescents, but following on from the observation that UPF consumption was higher in young people other researchers have looked specifically at adolescents.

Chavez-Uglade et al (2024) in a UK based study looked at 2,992 adolescents (age 11-18) and considered two specific time periods 2008/9 and ten years later 2018/2019.  They found that the mean consumption of UPF was 65.9% of total energy intake, but that this decreased over the ten-year study period from 67.7% to 62.8%.  The highest UPF consumption was associated with males, lower socioeconomic status, living with obesity and living in the North of England.

In their UK prospective study Rauber et al. (2020) found overall UPF consumption was higher in men than in women and UPF consumption was inversely correlated with age and socioeconomic status.  An earlier study of 2,174 individuals in the UK (Adams and White, 2015) confirmed the relationship between gender, age and UPF, but did not find a correlation between UPF consumption and socioeconomic status. They did find that the most healthy diets were consumed in higher SES households.

A similar pattern is seen in other countries.  A US based cross sectional study of 23,847 people, including children, found that 60% of calories came from UPF in the period 2007-2012 and that UPF consumption increased over the study period.  UPF consumption was higher in young people, those on low incomes and those with lower educational attainment (Baraldi  et al. 2018).  A cross-sectional study in Australia (Marchese et al. 2022) with 8,029 participants found that UPF consumption was higher in young people, those living with area level disadvantage and lower levels of education and income.  20,103 participants including children took part in a cross-sectional study in Canada (Polsky et al. 2024).  UPF consumption was highest in children and adolescents and more UPF was consumed in households experiencing food insecurity. Households of both recent and long-term immigrants consumed less UPF.  Males consumed more UPF than females and there was a small relationship between UPF consumption and education whereby those with the lower education levels consumed more UPF. 

The apparent relationship between socioeconomic status and UPF consumption may be explained by the low cost of UPF.  The FPro scale has been used to demonstrate the relationship between food processing and food price in the US. The authors found that a 10% increase in FPro score equated to an 8.7% decrease in price per calorie.   This is an average across all food categories, but it is much bigger in some categories.  For example, for soups and stews the decrease in price is 24.3% for each 10% increase in FPro score.  The cheaper products are more likely to be purchased by people from lower socioeconomic groups contributing to the observed differences in health outcomes between socioeconomic groups (Total life expectancy and healthy life years are both strongly correlated with socioeconomic status such that lower socioeconomic groups have shorter and less healthy lives).

The explanation for the inconsistent findings on socioeconomic status as defined by income and UPF consumption may be due to differences in price across UPF types. Whilst some UPF is cheap as seen above with the FPro data, some categories of UPF are marketed as premium products and purchased by higher income groups.

There is a belief that following a particular diet which excludes certain food items such as a vegetarian, vegan or pescetarian diet may be inherently more healthy.  A recent study by Chang et al. (2024) using data from the UK Biobank and covering 199,502 participants investigated whether there was a difference in UPF consumption across diet types.  Participants completed food questionnaires and they were assigned to vegan, vegetarian, pescetarian, flexitarian, low red meat and regular red meat diet groups and food items were classified according to the NOVA classification.  Participants had a mean age of 58.2 years, 55.1% were women and 96% were white.  Meat eating and flexitarian diets dominated the participant cohort. The study showed that there was no relationship between diet type and UPF consumption.  Overall consumption of UPF represented 20% of daily food intake and 46% of daily calorie intake, lower than the average for the UK.  All the diets studied were above the UK guidelines for sugar intake indicating the high level of UPF in all the diets.

Conclusion

UPF is a major contributor to the diet in the Uk and other developed countries.  It is characterised as food that has poor nutritional content, high in fat, sugar and salt, and as food that has undergone several processing steps usually with the addition of many ingredients.  Consumption of UPF is linked to overweight/obesity and adverse health outcomes.

UPF though is a broad categorisation and it is likely that various types of UPF influence health outcomes differently. A more sophisticated classification system may help researchers identify what it is in UPF that causes the adverse health outcomes. Today’s evidence indicates that the nutritional value of the food has a major effect with a small additional contribution from the processing.

Further research is required to understand properly why processing leads to adverse health outcomes. UPF is easy to eat and highly palatable leading to increased consumption.  The food structure makes nutrients rapidly available leading to rapid spikes in blood levels not seen with minimally processed foods. The industrial ingredients in the food and the materials in the packaging may have an adverse metabolic impact directly or acting through the gut microbiome.

References

Askari M, Heshmati J, Shahinfar H, Tripathi N, Daneshzad E. Ultra-processed food and the risk of overweight and obesity: a systematic review and meta-analysis of observational studies. Int J Obes (Lond). 2020 Oct;44(10):2080-2091. doi: 10.1038/s41366-020-00650-z. Epub 2020 Aug 14. PMID: 32796919.

Baraldi LG, Martinez Steele E, Canella DS, Monteiro CA. Consumption of ultra-processed foods and associated sociodemographic factors in the USA between 2007 and 2012: evidence from a nationally representative cross-sectional study. BMJ Open. 2018 Mar 9;8(3):e020574. doi: 10.1136/bmjopen-2017-020574. PMID: 29525772; PMCID: PMC5855172.

Barrett EM, Shi P, Blumberg JB, O’Hearn M, Micha R, Mozaffarian D. Food Compass 2.0 is an improved nutrient profiling system to characterize healthfulness of foods and beverages. Nat Food. 2024 Nov;5(11):911-915. doi: 10.1038/s43016-024-01053-3. Epub 2024 Oct 8. PMID: 39379671; PMCID: PMC11578874.

Braesco V, Souchon I, Sauvant P, Haurogné T, Maillot M, Féart C, Darmon N. Ultra-processed foods: how functional is the NOVA system? Eur J Clin Nutr. 2022 Sep;76(9):1245-1253. doi: 10.1038/s41430-022-01099-1. Epub 2022 Mar 21. PMID: 35314769; PMCID: PMC9436773

Calixto Andrade G, Julia C, Deschamps V, Srour B, Hercberg S, Kesse-Guyot E, Allès B, Chazelas E, Deschasaux M, Touvier M, Augusto Monteiro C, Bertazzi Levy R. Consumption of Ultra-Processed Food and Its Association with Sociodemographic Characteristics and Diet Quality in a Representative Sample of French Adults. Nutrients. 2021 Feb 20;13(2):682. doi: 10.3390/nu13020682. PMID: 33672720; PMCID: PMC7924346.

Chang K, Parnham JC, Rauber F, Levy RB, Huybrechts I, Gunter MJ, Millett C, Vamos EP. Plant-based dietary patterns and ultra-processed food consumption: a cross-sectional analysis of the UK Biobank. EClinicalMedicine. 2024 Nov 14;78:102931. doi: 10.1016/j.eclinm.2024.102931. PMID: 39619237; PMCID: PMC11605131.

Chavez-Ugalde IY, de Vocht F, Jago R, Adams J, Ong KK, Forouhi NG, Colombet Z, Ricardo LIC, van Sluijs E, Toumpakari Z. Ultra-processed food consumption in UK adolescents: distribution, trends, and sociodemographic correlates using the National Diet and Nutrition Survey 2008/09 to 2018/19. Eur J Nutr. 2024 Oct;63(7):2709-2723. doi: 10.1007/s00394-024-03458-z. Epub 2024 Jul 17. PMID: 39014218; PMCID: PMC11490440.

Dicken SJ, Batterham RL. The Role of Diet Quality in Mediating the Association between Ultra-Processed Food Intake, Obesity and Health-Related Outcomes: A Review of Prospective Cohort Studies. Nutrients. 2021 Dec 22;14(1):23. doi: 10.3390/nu14010023. PMID: 35010898; PMCID: PMC8747015.

Dicken SJ, Dahm CC, Ibsen DB, Olsen A, Tjønneland A, Louati-Hajji M, Cadeau C, Marques C, Schulze MB, Jannasch F, Baldassari I, Manfredi L, Santucci de Magistris M, Sánchez MJ, Castro-Espin C, Palacios DR, Amiano P, Guevara M, van der Schouw YT, Boer JMA, Verschuren WMM, Sharp SJ, Forouhi NG, Wareham NJ, Vamos EP, Chang K, Vineis P, Heath AK, Gunter MJ, Nicolas G, Weiderpass E, Huybrechts I, Batterham RL. Food consumption by degree of food processing and risk of type 2 diabetes mellitus: a prospective cohort analysis of the European Prospective Investigation into Cancer and Nutrition (EPIC). Lancet Reg Health Eur. 2024 Sep 16;46:101043. doi: 10.1016/j.lanepe.2024.101043. PMID: 39529810; PMCID: PMC11551512.

Simona Esposito, Alessandro Gialluisi, Augusto Di Castelnuovo, Simona Costanzo, Antonietta Pepe, Emilia Ruggiero, Amalia De Curtis, Mariarosaria Persichillo, Chiara Cerletti, Maria Benedetta Donati, Giovanni de Gaetano, Licia Iacoviello, Marialaura Bonaccio, Licia Iacoviello, Giovanni de Gaetano, Maria Benedetta Donati, Chiara Cerletti, Marialaura Bonaccio, Americo Bonanni, Simona Costanzo, Amalia De Curtis, Augusto Di Castelnuovo, Alessandro Gialluisi, Francesco Gianfagna, Mariarosaria Persichillo, Teresa Di Prospero, Jos Vermylen, Renzo Pegoraro, Antonio Spagnolo, Deodato Assanelli, Livia Rago, Simona Costanzo, Marco Olivieri, Sabatino Orlandi, Teresa Panzera, Augusto Di Castelnuovo, Marialaura Bonaccio, Simona Costanzo, Simona Esposito, Alessandro Gialluisi, Anwal Ghulam, Francesco Gianfagna, Roberta Parisi, Antonietta Pepe, Emilia Ruggiero, Sukshma Sharma, Amalia De Curtis, Concetta Civitillo, Alisia Cretella, Sara Magnacca, Fabrizia Noro, Mariarosaria Persichillo, Francesca Bracone, Giuseppe Di Costanzo, Sabrina Franciosa, Martina Morelli, Teresa Panzera, Americo Bonanni, Ultra-processed food consumption is associated with the acceleration of biological aging in the Moli-sani Study, The American Journal of Clinical Nutrition, Volume 120, Issue 6, 2024, Pages 1432-1440, ISSN 0002-9165, https://doi.org/10.1016/j.ajcnut.2024.10.006. (https://www.sciencedirect.com/science/article/pii/S000291652400813X)

Fang Z, Rossato SL, Hang D, Khandpur N, Wang K, Lo CH, Willett WC, Giovannucci EL, Song M. Association of ultra-processed food consumption with all cause and cause specific mortality: population based cohort study. BMJ. 2024 May 8;385:e078476. doi: 10.1136/bmj-2023-078476. PMID: 38719536; PMCID: PMC11077436.

Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, Chung ST, Costa E, Courville A, Darcey V, Fletcher LA, Forde CG, Gharib AM, Guo J, Howard R, Joseph PV, McGehee S, Ouwerkerk R, Raisinger K, Rozga I, Stagliano M, Walter M, Walter PJ, Yang S, Zhou M. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell Metab. 2019 Jul 2;30(1):67-77.e3. doi: 10.1016/j.cmet.2019.05.008. Epub 2019 May 16. Erratum in: Cell Metab. 2019 Jul 2;30(1):226. doi: 10.1016/j.cmet.2019.05.020. Erratum in: Cell Metab. 2020 Oct 6;32(4):690. doi: 10.1016/j.cmet.2020.08.014. PMID: 31105044; PMCID: PMC7946062.

Hamano S, Sawada M, Aihara M, Sakurai Y, Sekine R, Usami S, Kubota N, Yamauchi T. Ultra-processed foods cause weight gain and increased energy intake associated with reduced chewing frequency: A randomized, open-label, crossover study. Diabetes Obes Metab. 2024 Nov;26(11):5431-5443. doi: 10.1111/dom.15922. Epub 2024 Sep 12. PMID: 39267249.

Juul F, Parekh N, Martinez-Steele E, Monteiro CA, Chang VW. Ultra-processed food consumption among US adults from 2001 to 2018. Am J Clin Nutr. 2022 Jan 11;115(1):211-221. doi: 10.1093/ajcn/nqab305. PMID: 34647997.

Lane MM, Gamage E, Du S, Ashtree DN, McGuinness AJ, Gauci S, Baker P, Lawrence M, Rebholz CM, Srour B, Touvier M, Jacka FN, O’Neil A, Segasby T, Marx W. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024 Feb 28;384:e077310. doi: 10.1136/bmj-2023-077310. PMID: 38418082; PMCID: PMC10899807.

Marchese L, Livingstone KM, Woods JL, Wingrove K, Machado P. Ultra-processed food consumption, socio-demographics and diet quality in Australian adults. Public Health Nutr. 2022 Jan;25(1):94-104. doi: 10.1017/S1368980021003967. Epub 2021 Sep 13.

Mendoza K, Smith-Warner SA, Rossato SL, Khandpur N, Manson JE, Qi L, Rimm EB, Mukamal KJ, Willett WC, Wang M, Hu FB, Mattei J, Sun Q. Ultra-processed foods and cardiovascular disease: analysis of three large US prospective cohorts and a systematic review and meta-analysis of prospective cohort studies. Lancet Reg Health Am. 2024 Sep 2;37:100859. doi: 10.1016/j.lana.2024.100859. PMID: 39286398; PMCID: PMC11403639.

Monteiro CA, Moubarac JC, Levy RB, Canella DS, Louzada MLDC, Cannon G. Household availability of ultra-processed foods and obesity in nineteen European countries. Public Health Nutr. 2018 Jan;21(1):18-26. doi: 10.1017/S1368980017001379. Epub 2017 Jul 17. PMID: 28714422; PMCID: PMC10260838.

Monteiro CA, Cannon G, Levy RB, Moubarac JC, Louzada ML, Rauber F, Khandpur N, Cediel G, Neri D, Martinez-Steele E, Baraldi LG, Jaime PC. Ultra-processed foods: what they are and how to identify them. Public Health Nutr. 2019 Apr;22(5):936-941. doi: 10.1017/S1368980018003762. Epub 2019 Feb 12. PMID: 30744710; PMCID: PMC10260459.

Mozaffarian D, El-Abbadi NH, O’Hearn M, Erndt-Marino J, Masters WA, Jacques P, Shi P, Blumberg JB, Micha R. Food Compass is a nutrient profiling system using expanded characteristics for assessing healthfulness of foods. Nat Food. 2021 Oct;2(10):809-818. doi: 10.1038/s43016-021-00381-y. Epub 2021 Oct 14.

Pagliai G, Dinu M, Madarena MP, Bonaccio M, Iacoviello L, Sofi F. Consumption of ultra-processed foods and health status: a systematic review and meta-analysis. Br J Nutr. 2021 Feb 14;125(3):308-318. doi: 10.1017/S0007114520002688. Epub 2020 Aug 14. PMID: 32792031; PMCID: PMC7844609.

Polsky JY, Jovovic S, Nardocci M, Moubarac JC. Socio-demographic correlates of ultra-processed food consumption in Canada. Public Health Nutr. 2024 Sep 26;27(1):e180. doi: 10.1017/S1368980024001630. PMID: 39324345; PMCID: PMC11504217.

Ravandi, B., Ispirova, G., Sebek, M. et al. Prevalence of processed foods in major US grocery stores. Nat Food (2025). https://doi.org/10.1038/s43016-024-01095-7

Rodrigo R Petres, Carmen Cecilia Tadini and Paolo Sobral. The NOVA Classification: a critical perspective in food science. Tends in Food Science and Technology, August 2021. DOI: 10.1016/j.tifs.2021.08.010

Rauber F, da Costa Louzada ML, Steele EM, Millett C, Monteiro CA, Levy RB. Ultra-Processed Food Consumption and Chronic Non-Communicable Diseases-Related Dietary Nutrient Profile in the UK (2008⁻2014). Nutrients. 2018 May 9;10(5):587. doi: 10.3390/nu10050587. PMID: 29747447; PMCID: PMC5986467.

Rauber F, Steele EM, Louzada MLDC, Millett C, Monteiro CA, Levy RB. Ultra-processed food consumption and indicators of obesity in the United Kingdom population (2008-2016). PLoS One. 2020 May 1;15(5):e0232676. doi: 10.1371/journal.pone.0232676. PMID: 32357191; PMCID: PMC7194406.

Christina R Sadler, Terri Grassby, Kathryn Hart, Monique Raats, Milka Sokolovic, Lada Timotijevic Processed food classification: Conceptualisation and challenges.  Trends in Food Science & Technology 112 (2021) 149–162

Salame C, Javaux G, Sellem L, Viennois E, de Edelenyi FS, Agaësse C, De Sa A, Huybrechts I, Pierre F, Coumoul X, Julia C, Kesse-Guyot E, Allès B, Fezeu LK, Hercberg S, Deschasaux-Tanguy M, Cosson E, Tatulashvili S, Chassaing B, Srour B, Touvier M. Food additive emulsifiers and the risk of type 2 diabetes: analysis of data from the NutriNet-Santé prospective cohort study. Lancet Diabetes Endocrinol. 2024 May;12(5):339-349. doi: 10.1016/S2213-8587(24)00086-X. PMID: 38663950.

Schnabel L, Kesse-Guyot E, Allès B, Touvier M, Srour B, Hercberg S, Buscail C, Julia C. Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France. JAMA Intern Med. 2019 Apr 1;179(4):490-498. doi: 10.1001/jamainternmed.2018.7289. PMID: 30742202; PMCID: PMC6450295.

Sellem L, Srour B, Javaux G, Chazelas E, Chassaing B, Viennois E, Debras C, Salamé C, Druesne-Pecollo N, Esseddik Y, de Edelenyi FS, Agaësse C, De Sa A, Lutchia R, Louveau E, Huybrechts I, Pierre F, Coumoul X, Fezeu LK, Julia C, Kesse-Guyot E, Allès B, Galan P, Hercberg S, Deschasaux-Tanguy M, Touvier M. Food additive emulsifiers and risk of cardiovascular disease in the NutriNet-Santé cohort: prospective cohort study. BMJ. 2023 Sep 6;382:e076058. doi: 10.1136/bmj-2023-076058. PMID: 37673430; PMCID: PMC10480690.

[1] BMI = weight in kilograms divided by height in meters squared (kg/m²)