Customers smoke and drink beer with their food at a stall in Beijing: Tobacco, alcohol and overeating are among the leading causes of noncommunicable disease in both rich and poor countries. (Niranjan Shrestha/AP)

In the arc of human history it has to count as a form of success that the biggest threat to health in the world today is too much — too much food, drink, pleasure and leisure.

For all but the last few blinks of time, most people died of such things as cold, starvation, childbirth, accident, violence and microbes that hand-delivered infection to every organ in the body.

Of course, lots of people still die in the old ways. But the major killers now are a different set of enemies, a drab regiment marching under the banner of “noncommunicable disease.” The big ones are cardiovascular ailments (heart attacks and stroke mostly); cancer; chronic lung diseases such as emphysema; and diabetes. There are many others — kidney failure, cirrhosis, arthritis — nearly as important.

Fueled by behavior-driven epidemics of smoking, obesity and inactivity, they are taking a toll around the globe, hitting poor nations as well as the rich.

“NCDs” are what the human body will encounter if it lives long enough. That makes them a hard target. They’re not like smallpox (eradicated) or polio (headed that way) or malaria (gone from Europe and North America). They’ll always be with us.

But they can be prevented and delayed and their effects treated, and what’s now clear is that without a concerted effort to do that, the world is in big trouble. That’s the message public-health experts, epidemiologists and activists delivered to world leaders at the United Nations this week.

NCDs now account for 63 percent of deaths worldwide and are the leading cause of death everywhere but sub-Saharan Africa, where infections, malnutrition and deaths associated with childbirth still dominate. Many of the risk factors underlying them are already more commonplace in poor countries than in rich ones, or are rising quickly. Elevated blood pressure, for example, is more common in low-income countries such Zambia and Burma, and in middle-income countries such as Indonesia and Argentina, than it is in the United States.

But ill health and early death are just part of the problem. Increasingly, noncommunicable diseases are seen as a threat to prosperity. They consume personal wealth, cut workplace productivity and require vast amounts of spending on health care.

The average poor household in Nepal spends 10 percent of its income on cigarettes. In Russia, the average worker misses 10 days of work a year due to chronic illness or injury. A month’s worth of the four drugs people should take after a heart attack cost five days’ wages for the lowest-paid government worker in Brazil.

In the mega-countries of India and China, where lifestyle changes and economic growth are galloping hand in hand, the future is especially alarming. In 2004, Indians lost 7.1 million years of life by dying of heart attacks before age 60; that annual toll of premature death is projected to be 17.9 million years in 2030. Between 2006 and 2015 China will lose slightly more than half a trillion dollars in national income because of heart disease, stroke and diabetes.

A bigger challenge

So how much of this present can be changed and the future avoided? Quite a bit. At least that’s what scientific research, chance events in recent history and the opinions of experts say.

The prevention strategies, however, are more complicated and controversial — also more numerous and varied — than the ones that have proved so successful against infectious and maternal-and-child deaths.

Prevention of infectious and noncommunicable diseases both require two kinds of interventions. The first target individuals and are usually delivered by doctors and nurses. The second target populations and are delivered by government, or the things that government can influence.

Vaccines are the classic examples of the first. They’ve eradicated smallpox, tamed measles and made rare pathogens such as Haemophilus influenzae type B (Hib) even rarer. Their great advantage is they have to be given only a few times — sometimes just once — to do their work. Delivering chlorinated water in pipes is the second kind of intervention. No government action in the last two centuries has saved as many lives. And it goes vaccination one better: All that’s required to the reap the benefits is to turn on the tap.

With noncommunicable diseases, prevention is harder.

There’s no vaccine to prevent smoking (although scientists are working on one), no pill to make people exercise more or eat less. Drugs that control blood pressure or lower cholesterol have to be taken every day.

The obstacles to intervening in the life of whole communities are even larger. Efforts to change the fat and salt content of food can run into opposition by manufacturers and restaurants. Smoke-free workplace laws require action by lawmakers and force people to change their behavior, making them unpopular in some quarters. “Sin taxes” on tobacco, alcohol and soft drinks put a heavier burden on the poor than the affluent and also are frequently opposed by powerful commercial interests.

For these reasons, the control of noncommunicable disease has long emphasized messages delivered to individuals. Hippocrates gave dietary advice. Seventy years ago the New York Life Insurance Co. took out magazine advertisements offering weight-loss tips to men who noticed their shadows were growing bigger. Primary-care physicians today are taught to cram into 30-minute visits talk about exercise, smoking, fat and salt (as well as seat belts, safe sex, sleep and lots of other things).

But in the near half-century since the 1964 Surgeon General’s Report on Smoking and Health — which led the following year to pack warnings and later to a cascade of laws and campaigns that cut U.S. smoking in half — it’s been clear that population-wide interventions are essential.

“In the late ’80s or ’90s we realized that people can’t make individual behavior change unless the environment supports it and makes the ideal behavior easy and convenient,” said Ursula Bauer, director of chronic disease prevention and health promotion at the Centers for Disease Control and Prevention.

Before and after
Researchers have spent a lot of time trying to prove that population-wide interventions can improve health. (See accompanying story.) But the best evidence actually comes from “natural experiments” in which historical events create a “before” and “after” that can be compared.

Helena, the capital of Montana, enacted a public-smoking ban in June 2002. The following December it was suspended by a court. During that six-month period, admissions for heart attack fell by 40 percent at the only hospital in Helena that takes such cases. The rate then returned to its previous level. Heart attacks in nearby regions of Montana showed no such dip, suggesting Helena’s smoking ban, short as it was, had a measurable health effect.

Between 1991 and 1994, Poland experienced a 25 percent decline in its heart attack death rate after seeing that rate steadily rise for the previous three decades. Neither smoking rates nor blood cholesterol — two key risk factors for heart attacks — changed in those three years. But diet did. With the end of communist rule in 1989, there was a doubling of fruit and vegetable consumption, an end of consumer subsidies for meat, a big shift from animal to vegetable fats and a decline in egg and milk consumption.

The researchers who analyzed Poland’s decline in heart attack deaths believe they were caused by a decline in saturated and trans fat, which markedly increase people’s risk for heart attacks, especially if they already have extensive plaques in their arteries.

That effect of trans fat is the reason New York went after it in 2005.

The city health department first sent information to consumers, food suppliers and 30,000 restaurants urging them to substitute less hazardous oils for trans fats. But a year later nothing had changed, so the city’s health code was amended to require the substitution. By 2008, the percentage of restaurants using trans fat in food preparation had fallen from 50 to 1.6. While the the food industry opposed the regulation, there were no obvious economic effects, according to researchers writing in the Annals of Internal Medicine in 2009.

“Trans-fat restriction is now a largely unnoticed part of New York City life,” they wrote.

Brain as battleground

Unfortunately, most of the other changes that people and populations will have to make to reduce the burden of noncommunicable diseases won’t be so easy.

Food, alcohol and tobacco have the ability to change the way we feel and to make us want to feel that way again. Their effects employ brain pathways fine-tuned by millions of years of evolution. The neurons that blast serotonin, dopamine and acetylcholine when we consume salt, sugar, fat, nicotine and alcohol are the same ones that help us pay attention, motivate ourselves, and learn and remember.

That’s a big problem, argues David A. Kessler.

The author of “The End of Overeating,” Kessler headed the Food and Drug Administration for seven years under both Republican (George H.W. Bush) and Democratic (Bill Clinton) presidents. Changes in food labeling and a campaign to define cigarettes as drug delivery devices were key efforts of his tenure. He doesn’t think we’re going to be able to block these neural pathways without damaging human traits.

“Those circuits are not unique to food,” Kessler said in a recent interview. “I can give you a drug that will affect your appetite and cool them down, but you’re going to have to give me back a number of IQ points.” He said he was not speaking rhetorically.

Instead, it’s going to take other parts of the brain — the consciously thinking parts — to get people to eat less and eat better, he believes. That’s what happened with smoking. But the demonization of tobacco companies and ostracism of smokers that were essential to that campaign won’t work with food, which is essential for life.

Nevertheless, Kessler believes, we can learn to think differently — about certain foods, portion sizes, about eating everywhere and anytime — and government has tools to help. The former FDA commissioner, who acknowledges in his book that sugar, fat and salt “held remarkable sway over my behavior” for much of his life, thinks regulation of food advertising to children is one.

“Speech that is linked to reinforcing stimuli, and is nothing more than a cue in the addiction process, should not be accorded the same weight as speech that is informational,” he said.

The First Amendment doesn’t protect yelling “Fire!” in a crowded theater when there is no fire. Should it protect an advertisement for sugary cereal if the words lead to an unhealthy obsession with sweets? Kessler thinks it’s a question worth thinking about.

Will the tide turn?

There’s one other ingredient helpful to bending the curve of dangerous trends. It’s popular support for change, the sort of social action that has proven effective in the fight against AIDS.

Can this happen when the payoffs of the moment — “Let’s finish that bag of potato chips” and “I think I’ll skip the gym today” — are utterly different from the pain and suffering that often lies at the end of the road? Will people rise up to make themselves healthier and demand that their governments help them?

Some people think so.

“I am very, very optimistic about the creation of a social movement. The evidence is clear that it can be done,” said Sir George Alleyne, a physician who once headed the Pan American Health Organization and was a driving force behind this week’s U.N. meeting.

However, whether this will actually happen — and whether the tide of noncommunicable diseases can be turned back without it — is something that nobody can yet say.