Obesity, undernutrition and climate change are the biggest threats to the world population, linked by profit motives and policy inertia, a top commission said on Sunday, calling for a binding plan and trillions of dollars to thwart the dangers.

Daniel Kahneman, the psychologist who won the Nobel Prize in Economics, credits some recent public policy successes to the application of behavioural science. He helped establish this field and its “nudge” approach to changing the behaviour of large groups of people.

World Obesity and RTI International developed a model to estimate the economic impact of overweight and obesity from a societal perspective.

Currently there are 30% more obese people on the planet than undernourished people. And this has happened only within 15 years because 15 years ago it was exactly the opposite. And it’s occurring in countries that still have under nutrition.