Ultra-processed food (UPF) is linked to harm in every major organ system of the human body and poses a seismic threat to global health, according to the world’s largest review.

UPF is also rapidly displacing fresh food in the diets of children and adults on every continent, and is associated with an increased risk of a dozen health conditions, including obesity, type 2 diabetes, heart disease and depression.

The sharp rise in UPF intake worldwide is being spurred by profit-driven corporations using a range of aggressive tactics to drive consumption, skewer scientific debate and prevent regulation, the review of evidence suggests.

The findings, from a series of three papers published in the Lancet, come as millions of people increasingly consume UPF such as ready meals, cereals, protein bars, fizzy drinks and fast food.

In the UK and US, more than half the average diet now consists of UPF. For some, especially people who are younger, poorer or from disadvantaged areas, a diet comprising as much as 80% UPF is typical.

Evidence reviewed by 43 of the world’s leading experts suggests that diets high in UPF are linked to overeating, poor nutritional quality and higher exposure to harmful chemicals and additives.

A systematic review of 104 long-term studies conducted for the series found 92 reported greater associated risks of one or more chronic diseases, and early death from all causes.

One of the Lancet series authors, Prof Carlos Monteiro, professor of public health nutrition at the University of São Paulo, said the findings underlined why urgent action is needed to tackle UPF.

“The first paper in this Lancet series indicates that ultra-processed foods harm every major organ system in the human body. The evidence strongly suggests that humans are not biologically adapted to consume them.”

He and his colleagues in Brazil came up with the Nova classification system for foods. It groups them by level of processing, ranging from one – unprocessed or minimally processed foods, such as whole fruits and vegetables – to four: ultra-processed.

This category is made up of products that have been industrially manufactured, often using artificial flavours, emulsifiers and colouring. They include soft drinks and packaged snacks, and tend to be extremely palatable and high in calories but low in nutrients.

They are also designed and marketed to displace fresh food and traditional meals, while maximising corporate profits, Monteiro said.

Critics argue UPF is an ill-defined category and existing health policies, such as those aimed at reducing sugar and salt consumption, are sufficient to deal with the threat.

Monteiro and his co-authors acknowledged valid scientific critiques of Nova and UPF – such as lack of long-term clinical and community trials, an emerging understanding of mechanisms, and the existence of subgroups with different nutritional values.

However, they argued future research must not delay immediate action to tackle the scourge of UPF, which they say is justified by the current evidence.

“The growing consumption of ultra-processed foods is reshaping diets worldwide, displacing fresh and minimally processed foods and meals,” Monteiro warned.

“This change in what people eat is fuelled by powerful global corporations who generate huge profits by prioritising ultra-processed products, supported by extensive marketing and political lobbying to stop effective public health policies to support healthy eating.”

The second paper in the series proposes policies to regulate and reduce UPF production, marketing and consumption. Although some countries have brought in rules to reformulate foods and control UPF, “the global public health response is still nascent, akin to where the tobacco control movement was decades ago”, it said.

The third paper says that global corporations, not individual choices, are driving the rise of UPF. UPF is a leading cause of the “chronic disease pandemic” linked to diet, with food companies putting profit above all else, the authors said.

The main barrier to protecting health is “corporate political activities, coordinated transnationally through a global network of front groups, multi-stakeholder initiatives, and research partners, to counter opposition and block regulation”.

Series co-author Prof Barry Popkin, from the University of North Carolina, said: “We call for including ingredients that are markers of UPFs in front-of-package labels, alongside excessive saturated fat, sugar, and salt, to prevent unhealthy ingredient substitutions, and enable more effective regulation.”

The authors also proposed stronger marketing restrictions, especially for adverts aimed at children, as well as banning UPF in public places such as schools and hospitals and putting limits on UPF sales and shelf space in supermarkets.

One success story is Brazil’s national school food programme, which has eliminated most UPF and will require 90% of food to be fresh or minimally processed by 2026.

Scientists not involved in the series broadly welcomed the review of evidence but also called for more research into UPF, cautioning that association with health harm may not mean causation.