Nearly a billion people in the world are hungry and another two billion are eating too much of the wrong foods, causing epidemics of obesity, heart disease and diabetes, both issues that could be made worse by climate change, according to the Lancet Commission on Obesity. (Photo: AFP)

To defeat the intertwined pandemics of obesity, hunger and climate change, governments must curb the political influence of major corporations, said a major report Monday calling for a 'global treaty' similar to one for tobacco control.

But this will not happen unless ordinary citizens demand a "radical rethink" of the relationship between policymakers and business, nearly four dozen experts from The Lancet Commission on Obesity concluded.

Powerful opposition from vested interests, lack of political leadership, and insufficient societal demand for change are preventing action," they said in a statement.

Nearly a billion people are hungry and another two billion are eating too much of the wrong foods, causing epidemics of obesity, heart disease and diabetes. Unhealthy diets account for up to 11 million premature deaths every year, according to the most recent Global Disease Burden report.

"Malnutrition in all its forms – including undernutrition and obesity – is by far the biggest cause of ill-health and premature deathy globally. Both undernutrition and obesity are expected to be made significantly worse by climate change," said Commission co-chair Boyd Swinburn, a professor at the University of Aukland.

The way in which food is currently produced, distributed and consumed not only fuels the hunger and obesity pandemics, it also generates 25 to 30 per cent of planet-warming greenhouse gas emissions.

Cattle production alone accounts for more than have of those gases, in the form of methane-laden flatulence and CO2 when forests, especially in Brazil, are being cleared to accommodate livestock.

A transport system dominated by cars contributes another 15 to 25 per cent of emissions, and supports a sedentary lifestyle. "Underpinning all of these are weak political governance, the unchallenging economic pursuit of GPD growth, and the powerful commercial engineering of overconsumption," the report said.

"Undernutrition is declining too slowly to meet global targets, no country has reversed its obesity epidemic, and comprehensive policy responses to the threat of climate change have barely begun."

Despite 30 years of warnings from science about the dire impacts of global warming, CO2 emissions hit record levels in 2017 and again last year. Since all these problems are interwoven, the answers must be too, the researchers emphasised.

"Joining the three pandemics" – hunger, obesity, climate – "together as 'The Global Syndemic' allows us to consider common drivers and shared solutions."