Numerous statements containing ultra-processed food (UPF) guidance and recommendations have emerged in 2023.

The British Nutrition Foundation (BNF) published its position statement on UPFs, entitled The Concept Of Ultra-Processed Foods (UPF), in April 2023, after a review of scientific literature. It closely aligns with guidance by the Academy of Nutrition Sciences and the UK government’s Scientific Advisory Committee on Nutrition, published in June and July 2023, respectively. The Nordic Nutrition Recommendations on UPFs were also published in 2023, though they did not produce any specific recommendations.

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However, confusion exists following reports surrounding the connection between UPF researchers and corporates selling such products following a press briefing organised by the Science Media Centre, which sparked controversy.

Research outcomes cause confusion

In response to the marketing of highly processed, nutrient-poor foods to poorer populations in South America, research groups wanted to test the idea that consuming processed foods causes ill health, says Professor Pete Wilde from the Food Innovation and Health Programme at the Quadram Institute of Norwich University, who was also present at the SMC briefing.

Several observational studies have indicated consuming foods categorised as UPFs is associated with less healthy overall diets and specific health outcomes, such as increased risk of obesity, cardiovascular disease or type 2 diabetes. Bridget Benelam, nutrition scientist at British Nutrition Foundation (BNF) told Ingredients Network: “We acknowledge the association between high intakes of UPF and poor health outcomes, including heart disease, type 2 diabetes, obesity and cancer.”

However, as noted by Dr Laura Fernández Celemín, director general of non-profit organisation, the European Food Information Council (EUFIC), “… observational studies such as these cannot prove causation. It can be very difficult to rule out the contribution of confounding factors to the found associations, such as energy intake, BMI, and socioeconomic status.”

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Additionally, these studies often collect data on the consumption levels of UPFs using food frequency questionnaires that have yet to be validated for this purpose. These can lead to misclassifying foods in the UPF categories and misinterpreting health associations. “It’s still unclear to what extent any associations can be explained by established relationships between the nutritional content of foods and health,” says Dr Celemin. “The definition and classification of UPF are not universally agreed upon by food scientists or nutrition and public health agencies and have been criticised for being difficult to apply consistently.”

NOVA classification

The NOVA classification is, some may argue, the closest to a definition. It classifies foods according to their degree of processing, from unprocessed to ultra-processed. The classification is used to assess foods in extensive observational and epidemiological studies on health. “Many studies have used this classification, and most show that increased consumption of UPF in a diet is detrimental to health,” Professor Pete Wilde, Food Innovation and Health Programme, Quadram Institute of Norwich University, said.

“This is nothing new,” adds Wilde. However, the NOVA’s system and UPF classification do not incorporate nutritional quality into its definition, Wilde says. Research has examined the physiological mechanisms by which processed foods and UPFs can impact health. These mechanisms include high energy density, wherby food is rich in fat and sugar but poor in micronutrients such as vitamins, minerals, and fibre.

A lack of a “matrix” effect means food is rapidly consumed and digested, which can also indicate the relationship between UPF and health. Poor appetite control through rapid digestion, which leads to rapid return of hunger, is also present, along with hyper-palatable, which relates to food with high salt and additives, which can drive unhealthy eating behaviours.

The Kevin Hall study was a crossover trial showing that consuming UPFs led to weight gain. The study was ad libitum so individuals could eat as much or as little of the foods presented. Those on the UPF diets generally consumed more calories. Several high-profile calls for regulation on the consumption of UPFs resulted.

Wilde: ‘Most, if not all, foods are not simply good or bad but a mixture of both’

Following consumer trends and government regulation, food companies have developed foods with demonstrable health benefits such as lower energy density, higher fibre content, and reduced salt. “Yet these foods are considered UPFs and, therefore, unhealthy,” says Wilde.

Various foods can be classified as UPFs, which may make food less healthy. These are foods generally recommended to limit within a healthy diet, such as soft drinks, chocolate, and fried snacks. However, other examples, like wholemeal bread and vegetable-based sauces, may also be considered UPF, which can be part of a healthy dietary pattern.

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“Most, if not all, foods are not simply good or bad but a mixture of both,” says Wilde. The health benefits or harms may also be affected by how much you consume. Therefore, to help consumers navigate their food environment, health professionals and government public health agencies can help consumers identify and choose healthier processed food options while promoting reducing or avoiding less healthy options such as processed meats and products high in salt, sugar, and saturated fat.

“Classifying all UPFs as currently defined as unhealthy may, on the one hand, improve the diets of some sectors of the population but may also be counterproductive and drive consumers away from foods that could confer health benefits,” says Wilde. Further, it may also discourage the food industry from developing healthier food products.

The food industry needs further research to independently determine the impact on health, Wilde continues, and support a regulatory process that enables clear and accurate communication of the health impacts. “Most food companies want their customers to live long and healthy lives so they will continue to buy their products, so these foods need to be safe and healthy,” Wilde adds.