A national forecast released this week says obesity rates won't reach quite the levels of earlier predictions, but will settle in at around 42 percent of adults by 2030. That includes an increase in the number of severely obese — those 100 pounds or more overweight. And while the government talks about solutions to the problem, some experts wonder if they've gotten it wrong.

About one-third of American adults are now obese. While the prediction of 42 percent is high, it's not as bad as earlier predictions, according to Associated Press medical writer Lauran Neergaard. It is, however, still a growing number — just growing a little less robustly than had been projected.

"We still have a very serious problem," obesity specialist Dr. William Dietz of the Centers for Disease Control and Prevention told reporters.

The new government forecast, prepared by researchers led by Duke University, says those who are already obese are getting heavier and that by 2030, 11 percent of adults will be 100 or more pounds overweight. They note that being overweight increases the risk of having many ailments, but the most heavy are at the highest risk and are also the most costly to treat. "Already, conservative estimates suggest obesity-related problems account for at least 9 percent of the nation's yearly health spending, or $150 billion a year," Neergaard writes.

During a meeting of CDC anti-obesity campaigners, the experts noted some progress, including a slowing of the increase in obesity rates. But Americans overall are not losing weight, either.

National data says about 17 percent of American kids were obese in 2009 and 2010, which is about what it was a decade before. The rate for both boys and men are up slightly, though no one's sure why.

AP says the CDC-funded forecast uses some factors known to influence obesity rates, such as food prices, the availability of fast food and unemployment to help estimate what's coming. The increase in the number of people between 45 and 64 is a factor, too, since that group is "most likely to be obese," as Duke University health conomist ERic Finkelstein explained to Neergaard.

The CDC says more than 78 million American adults weight have a body mass index of 30, which means they're not just overweight, but obese.

On Monday Daily Beast and Newsweek blogger Gary Taubes joined those questioning whether the experts are going after the right targets in efforts to shed our collective excess pounds.

He notes that the government "has spent hundreds of millions telling Americans to exercise more and eat less. But the country is getting heavier every year. It's time to change the way we think about fat."

Although national efforts, including a four-part HBO documentary, "The Weight of the Nation," due out next week, focus on the calories-eaten-calories-burned equation as the answer to maintaining a healthy weight, it may not be that simple, he says. Why, he wonders, were there so many fat kids during the Great Depression, when food was anything but plentiful?

The issue with treating the obesity epidemic like a simple math problem of not burning more calories than you eat, as an ongoing multilevel awareness campaign does, he notes, is that the solutions promoted are the same ones that have been touted as the answer for 100 years "and they just haven't worked."

That calorie equation is not the only theory, though it garners the most attention. Taubes points out an "alternative theory" implicates refined sugars and grains due to how they affect the hormone insulin, which controls fat storage. Its proponents believe not all caloris are the same. But that, he notes, would mean "changing the entire American food economy and rewriting our beliefs about what constitutes a healthy diet." It would also, he adds, explain the fat kids in the Depression.

"If this hypothesis is right, then the reason the anti-obesity efforts championed by the Institute of Medicine, the CDC and the National Institutes of Health haven't worked and won't work is not because we're not listening and not because we just can't say no, but because these efforts are not addressing the fundamental cause of the problem," Taubes writes. "Like trying to prevent lung cancer by getting smokers to eat less and run more, it won't work because the intervention is wrong."

While experts don't agree completely on what's causing the high obesity rates and there is such heated debate on what will cure it, pretty much everyone agrees there are serious potential and existing health risks related to it. Among those listed by WebMD are diabetes, heart disease, high blood pressure and certain kinds of cancer, among others.

For a body mass index calculator, visit the National Heart Lung and Blood Institute BMI page.

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