A new international report released today is calling for global action over obesity, under-nutrition and climate change.
The Lancet Obesity Commission report was commissioned by the Lancet and co-chaired by Boyd Swinburn of the Auckland University School of Population Health.
It says malnutrition in all its forms, including obesity, under-nutrition and "other dietary risks", is the leading cause of poor health globally.
It adds, "In the near future the health effects of climate change will considerably compound these health challenges."
Specifically on obesity, the 62-page report says the prevalence of obesity is rising in every region of the world.
"No country has successfully reversed its epidemic because the systematic and institutional drivers of obesity remain largely unabated."
It says many evidence-based policy recommendations to halt and reverse obesity rates have been endorsed by member states at successive World Health Assembly meetings over nearly three decades, "but have not yet been translated into meaningful and measurable change".
The report describes this as patchy progress, adding, "Politicians are either intimidated by industry opposition or they might hold beliefs that education and market-based solutions that are grounded in neoliberal economic and governance models are sufficient to reverse the obesity epidemic."
It adds there is insufficient public demand for action to overcome industry opposition and governance reluctance.
"This inertia exists despite the enormous health and economic costs and abundant media stories about obesity and diabetes in the last several decades."
It says globally over the past four decades there has been an eight times increase in obesity in girls to 5.6 percent and a 10 times increase in boys to 7.8 percent in 2016.
The rise in obesity prevalence in adults over the same period worldwide had also been "relentless", increasing to almost 15 percent in women and almost 11 percent in men.
"In 2015, excess bodyweight was estimated to affect 2 billion people worldwide, and accounted for approximately 4 million deaths and 120 million disability-adjusted life-years."
The estimated costs of obesity were about $US2 trillion annually, representing 2.8 percent of the world's Gross Domestic Product (GDP).
The report says obesity, under-nutrition and climate change are usually viewed as separate but share "key drivers" and fuel each other.
"For example, food systems not only drive the obesity and under-nutrition pandemics but also generate more than a quarter of global greenhouse gas emissions and about half of New Zealand's emissions," Professor Swinburn said.
The report's recommendations include a new global treaty on food systems - similar to ones on tobacco control and climate change - to mobilise action.
It also wants subsidies re-directed towards healthy and sustainable foods and energy; a global philanthropic fund of $US1 billion to support social movements that demand action; and "a seven-generations fund" to research and apply indigenous and traditional knowledge and views about living well while nurturing the environment.