Obesity costs world $2 trillion a year

The 2.1 billion overweight and obese people of the world -- nearly one-third of the planet's population -- are costing a whopping $2 trillion annually in health-care costs, lost productivity and expenditures to mitigate its impact, according to a new study.

It's the third worst economic burden the world faces, right after war and smoking, according to the report by McKinsey Global Institute, the research arm of the McKinsey consulting group. It's costing the world 2.8 percent of the global Gross Domestic Product, roughly equivalent to Russia's entire GDP. Obesity is costing the United States $663 billion a year, and the United Kingdom $70 billion, according to the report.

The number of overweight and obese people was up sharply last year over 1980, jumping approximately 2.5 times, according to an earlier study.

Unless the trend is halted half of the adult population will likely be overweight by 2030.

"Obesity is now a critical global issue, requiring a comprehensive intervention strategy rolled out at scale," said Richard Dobbs, lead author of the McKinsey study. "Any single intervention is likely to have only a small impact on its own."

The World Health Organization attributes 2.8 million deaths a year to excess body weight, linking it to type 2 diabetes, cancer and heart disease.