Food systems are the drivers of obesity and under-nutrition and they also generate more than a quarter of global greenhouse emissions, says a new Lancet report.

The Lancet Commission – a group of 43 world-leading experts in agriculture, economics, human rights and other fields – says the interplay of obesity, under-nutrition and climate change poses an enormous threat to humanity.

Malnutrition, whether it is under nutrition or obesity, was by far the biggest cause of ill-health and premature death globally, the Lancet obesity commissioner Professor Steven Allender, told the Sydney Morning Herald.

“Excess body weight affects two billion people worldwide, while two billion people also suffer from micronutrient deficiency and both problems are expected to be made significantly worse by climate change,” Professor Allender said.

“Food systems not only drive the obesity and under- nutrition pandemic but also generate more than a quarter of global greenhouse gas emissions, with cattle production accounting for more than half of these emissions.

“Car-dominated transportation systems support sedentary lifestyles and generate between 14 and 25 per cent of emissions,” Professor Allender said.

Climate change’s extreme weather events, droughts, and shifts in agriculture will drive up rates of under nutrition by increasingly threatening food security, according to the report.

The latest report is the second by the Lancet Commission on the impact of nutrition and food systems on human and planetary health.