Why public health warnings can backfire

Premature warnings to consumers to avoid eating ultra-processed food products are likely to have social costs and could harm the health of people experiencing food poverty – at least in the short term.

This is the clear message to policymakers in a newly published perspective article from Professors Alexandra Johnstone of the Rowett Institute of Nutrition and Health, University of Aberdeen and Eric Robinson of the University of Liverpool.

They say that until the link between ultra-processed foods (UPFs) and poor health is better understood, the focus of official public advice should remain on avoiding known threats: high fat, sugar and salt.

Issuing formal warnings about UPFs in Britain – which some other countries have done – could be counterproductive, causing some people to switch to alternatives that are not classified as ultra-processed but are less nutritious than what they previously consumed. they claim. .

And they highlight the potential “social costs to many people with more limited resources” of omitting convenient options and the potential negative mental health consequences for “those concerned about their health or living with eating disorders, especially if social circumstances prevent making avoiding UPFs difficult. “

The article—published in PLOS medicine as part of a collection on the subject of UPFs – concludes: “Based on the balance of current evidence, we do not believe it is appropriate to advise consumers to avoid all UPFs and we await further evidence to inform consumers of the need to limit the consumption of specific foods based on their degree or type of processing.

“We know with certainty that foods with a high energy density and/or a high content of saturated fat, salt or sugar are harmful to health and we must continue to advise consumers to limit the consumption of these foods. In the same way, we should encourage the consumption of health-promoting products. promoting foods such as fruits, vegetables and whole grains.

“Mechanistic uncertainty about food processing and health should not prevent an immediate and much-needed public health policy to regulate the food industry to reduce the promotion, availability and dominance of foods high in energy and/or saturated fat, salt or sugar to be dramatically reduced at national level. diets.

“However, mechanistic uncertainty should shape how it is communicated to the public and play a central role in determining public advice and emerging national dietary guidelines on UPFs and health risks in food processing.”

Pressure to issue guidelines against eating UPFs – which make up a significant portion of the national diet – has increased in the media and elsewhere due to consistent evidence from a growing number of observational studies that they are linked to poor health outcomes.

But many UPFs are also high in fat, sugar and salt and so far the Food Standards Agency believes that other possible causes of ill health from consuming them “have not yet been fully explained by science”, and are therefore no specific public guidance has been given. issued.

Food Standards Scotland (FSS) warned in March that “the focus on ultra-processed foods risks diverting attention from the key nutritional issues for which there is robust evidence for action, namely foods high in fat, salt and sugar. This gives FSS further impetus to provide clear consumer messages on this topic.”

FSS has since published its organizational position on this issue, together with consumer-oriented advice, reaffirming these conclusions.

Professor Johnstone said: “We must guard against the possibility that if we continue to research of the connections between some ultra-healthy foods. -processed foods and poor health.

“We need more high-quality mechanistic research in humans, using controlled diets, to discover the effects of nutritional profile and ultra-processing per se. Diet reformulation and diet quality are two key aspects of our food environment and continue to exist alongside affordability. challenges for the food system.”

Professor Robinson said: “Foods considered ultra-processed and high in fat, salt and/or sugar should be avoided, but some ultra-processed foods should not. We need to think very carefully about what advice is given to the public, rather than providing simplified and potentially misleading messages that make headlines.”