The world’s biggest ultra-processed food companies have filed scores of lawsuits challenging government policies that tackle junk diets, the Guardian can reveal. 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. Worldwide consumption is rising and UPF now makes up as much as half the average diet in many countries, including the UK, the US and Australia.

Governments around the world have adopted measures to fight back and safeguard the health of children and adults. Among the regulations are front-of-pack warning labels, marketing restrictions on unhealthy products to make them less alluring and taxes on junk food. Publicly, the world’s biggest UPF companies insist they support the policies, are committed to helping consumers make informed choices and want to be part of the solution.

But an investigation by the Guardian, in collaboration with academics, the non-profit newsroom Lighthouse Reports and a coalition of media partners across four continents, found many of these same companies are taking governments to court to overturn, weaken or delay the policies. In total, 235 lawsuits were lodged over health policies targeting UPF in Mexico, Colombia, Brazil, the US and the UK from 2010 to 2025, the investigation found. It is not clear who is behind every lawsuit.

However, three-quarters were filed by UPF manufacturers or trade associations representing them, the investigation found. Some of the corporations involved in the legal cases, which can be revealed for the first time, requested courts withhold their names. Of the cases filed by companies where the plaintiff was identifiable, 38% were brought by eight parent corporations: Coca-Cola, PepsiCo, Mondelēz, Kellogg’s, Danone, Ferrero, Xignux and Heartland Food Products Group.

Dozens of cases are ongoing. Of those that have been resolved, three-quarters were lost by the food giants. But the length of some of the legal battles added up to almost 600 years in court, the investigation found.

Some of the ultimately unsuccessful lawsuits delayed the adoption of vital public health policies for years, while also tying up government and public health officials in complex and expensive litigation. In the meantime, the lawsuits are prolonging the growing global public health crisis, and costing countries billions in legal and healthcare costs, experts say. While governments are being sued over policies aimed at tackling unhealthy diets, the amount of UPF consumed continues to expand, contributing to rising cases of obesity, type 2 diabetes, heart disease, mental ill health and other conditions.

The world’s biggest UPF firms would “not fight so hard” if policies to curb intake of their products were ineffective, said Marion Nestle, a professor of nutrition, food studies and public health at New York University. “The lawsuits tell us that public health measures reduce sales of unhealthful products.” While the majority of cases were eventually won by governments, experts said the intensive litigation by UPF companies suggested other objectives: slowing down the implementation of laws, limiting the desire and capacity of countries to enact other public health measures and chilling regulators.