Obesity has become a danger far greater than hunger. Yet amid the alarming stories about its harm to America’s health and economy, one bit of information has been drowned out: The percentage of U.S. adults who are obese appears to have plateaued.

According to data from the National Health and Nutrition Examination Survey, which measures the heights and weights of a representative sample of almost 6,000 Americans, the prevalence of obesity in 2009-2010 was essentially the same as in 2003-2008. Given that the rate had doubled from 1980 to 2000, this is positive news.

It should not, however, be reason to give up the fight. Rather, the findings lead us to twin conclusions: We can make gains against obesity, and we should find ways to accelerate that progress.

The U.S. prevalence remains disastrously high: Thirty-six percent of adults (78 million) and almost 17 percent of children (12.5 million) weigh enough in relation to their height to be considered obese. For Hispanic and Mexican-American women, the prevalence is more than 40 percent, and for black women, it’s over 58 percent.

The health risks are unambiguous: diabetes, heart disease, stroke, breast and colon cancer, liver and gallbladder disease, sleep apnea, osteoarthritis and infertility. Treating these and other problems costs $190 billion a year, more than a fifth of the nation’s medical bill.

Many causes have been clearly identified: Our plates bulge with dense, starchy, high-calorie foods, but hold fewer fruits and vegetables than nutrition guidelines recommend. We eat out and order in more than ever, as both parents work outside the home. Our office jobs are sedentary. Kids sit around indoors too much. We spend a great deal of time watching TV, moving little and absorbing ads for all sorts of cheap, sugary, salty foods.

As a species, we lack biological mechanisms to block our appetites at the point when we’ve eaten enough or, having overeaten, to hunger less for the next meal. To the contrary, our bodies are naturally adept at gaining fat.

Conquering obesity will require changing our “obesogenic” culture in such a way as to steer people, en masse, away from fattening habits and lead all of us to choose healthy foods in modest portions, and become more active.

This cannot be accomplished with one sweeping national policy, although the federal government can push for some useful changes. The 2010 health-care reform law, for example, requires restaurants and vending-machine operators with at least 20 locations to list the calorie content of their standard menu items. The Food and Drug Administration is working out the rules to make this happen.

The FDA is also working to update its labeling requirements for packaged food, aiming in part to make calorie information more prominent, on the front of the package. Britain has created a model for this, with its voluntary front-of-package labels in traffic-light colors: Fat, saturated fat, sugar and salt content are given with rankings of green for low, amber for medium and red for high.

We’d also like to see national agriculture policy changed to refocus crop and insurance subsidies away from corn, soybeans, wheat and cotton and toward vegetables.

But state and city policy makers can push for changes, too, and can arguably have the greater effect. Foods and eating habits have local qualities, after all. Obesity rates vary by state ― from 20 percent in Colorado (in 2010) to 34 percent in West Virginia. And each city and state has its own tolerance for government interference.

Not all county officials would be willing to demand, for example, that kids’ meals containing toys adhere to limits on calories and salt, as supervisors in San Francisco and Santa Clara, California, have done. But some cities might follow New York’s example and ban artificial trans fats in restaurants.

States can experiment with modifying the food environment in other ways. Iowa, for instance, has enhanced vending machines at highway rest stops by adding healthy snacks and providing traffic-light-colored nutritional labels.

Some cities might want to try putting pressure on restaurants to limit portion sizes, aiming for a weight-conscious 700 calories per meal, as has been proposed by scientists at the RAND Corp. Many local governments would no doubt resist such a step as “nannying,” but state and local health officials set various other standards for food and water, to prevent food-borne illness and contamination. Now that one in three adults are obese, it’s clear that calorie count is also an aspect of food safety.

Local officials can provide tax breaks and streamlined permitting processes to encourage fresh-food grocers and farmers’ markets to set up shop in neighborhoods that need them. They can zone neighborhoods to get housing developers to provide safe and convenient sidewalks.

We would especially like to see some cities follow the recommendation of many obesity experts ― including, most recently, the Institute of Medicine ― and put a penny-an-ounce tax on sugar-sweetened beverages. A study published this year suggested this could reduce per capita consumption by 15 percent. But it would be nice to find out for sure whether people would choose less fattening beverages if sodas cost more.

Although no one knows how well each strategy will work, there is good reason to think that the prevalence of obesity can be reduced in adults. As for children, a prime target for obesity prevention, they will be the subject of the next editorial on the subject.

(Bloomberg)