UNITED NATIONS— The U.N. health chief delivered an urgent call to action to world leaders on Monday: Stand up against the tobacco and fast food industries and promote healthy living or the cost of combating cancer, diabetes, and heart and lung disease, will devour your economic gains.

In a hard-hitting speech at the opening of the first-ever U.N. meeting on chronic diseases that account for nearly two-thirds of deaths worldwide, Margaret Chan, the World Health Organization director general, said “the root cause of these diseases are not being addressed, and widespread obesity is the telltale signal.”

If urgent action isn’t taken, she warned, “the rising financial and economic costs of these diseases will reach levels that are beyond the coping capacity of even the wealthiest countries in the world.”

Chan pointed to a newly released World Economic Forum and Harvard University study which estimated that over the next 20 years, noncommunicable diseases will cost the global economy more than $30 trillion. That represents 48 percent of the global GDP in 2010, the study said.

Worldwide, stroke and heart-related diseases account for nearly half of all noninfectious disease deaths — 17 million in 2008 alone, WHO says. Next is cancer (7.6 million deaths), followed by respiratory diseases such as emphysema (4.2 million). Diabetes caused 1.3 million deaths in 2008, but that’s misleading — most diabetics die of cardiovascular causes.

U.N. Secretary-General Ban Ki-moon told leaders and ministers that WHO estimates that deaths from noncommunicable diseases will increase by 17 percent in the next decade — and by 24 percent in Africa.

The U.N. chose to focus on the four diseases and their common risk factors at the two-day high-level meeting: tobacco use, alcohol abuse, unhealthy diets, physical inactivity and environmental carcinogens.

“The worldwide increase of noncommunicable diseases is a slow-motion disaster,” Chan said.

“This meeting must be a wake up call for governments at their highest level,” she said. “We plead for lifestyle changes and strict tobacco regulation. But health ministries acting alone cannot re-engineer societies in ways that protect entire populations from the well-known and easily modified risks that lead to these diseases.”

Chan said the rise of these diseases is being driven by urbanization and globalization of unhealthy lifestyles.

The results, she said, have been an almost doubling of worldwide obesity rates since 1980, and heavily marketed junk foods high in salt, trans-fats and sugar becoming staples in nearly every corner of the world.

Worldwide, over 40 million pre-school children and more than 50 percent of the urban population in some countries are obese or overweight, she said.

“Junk foods … are readily available and heavily marketed,” she said. “For a growing number of people they are the cheapest way to fill a hungry stomach.”

But Chan argued that the world doesn’t need to be fed with junk food, which leads to obesity, diabetes and heart disease.

“In some countries, care for diabetes consumes 15 percent of the national budget,” she said.

In large parts of the developing world, Chan said, these diseases are detected late, require costly hospital care, cost billions of dollars in lost national income and push millions of people below the poverty line every year.

“These diseases break the bank and they are largely preventable through cost-effective measures,” she said.

Fully implementing the U.N.’s anti-smoking Framework Convention on Tobacco Control, which over 170 countries have signed on to, “would bring the single biggest blow to heart disease, cancer, diabetes and respiratory disease,” she said.

“I call on heads of state and heads of government to stand (and) work hard against the despicable efforts of the tobacco industry to subvert this treaty,” Chan said. “We must stand firm against their open and extremely aggressive tactics against some governments.”

She said increasing tobacco taxes and prices are the most effective measures to cut smoking and “they bring significant revenue to your government — and the same is true for alcohol.”

In addition to switching from junk food to healthy foods, Chan said salt levels in processed foods are too high and must be cut.

Secretary-General Ban urged corporations that profit from selling processed foods to children “to act with the utmost integrity,” and those that profit from alcohol sales to promote moderation in drinking.

“And we can all end tobacco use,” he said.