Washington ? Despite government data that show a dramatic increase in obesity in the United States over the past 20 years, most Americans don’t think they have much of a weight problem, according to a new McClatchy-Ipsos poll.

The survey found that only 17 percent of those surveyed thought that obesity was a major problem for their families and themselves, while 33 percent said it was a minor problem and 49 percent said it was no problem at all.

Two-thirds judged themselves at healthy weights, and while 30 percent acknowledged that they were overweight, only 4 percent said they were very overweight.

That’s not how the Centers for Disease Control and Prevention sees the problem. Last year, the CDC reports, only one state — Colorado — had a prevalence of obesity of less than 20 percent. Thirty-two states had prevalences of 25 percent or greater, and six of those states — Alabama, Mississippi, Oklahoma, South Carolina, Tennessee and West Virginia — had prevalences of obesity of 30 percent or more.

The latest Behavioral Risk Factor Surveillance System survey data show that obesity in the U.S. is getting worse, said Liping Pan, a CDC epidemiologist and the lead author of the CDC’s obesity report. “If this trend continues we will likely see increases in health care costs for obesity-related diseases.”

Dr. William Dietz, the director of the CDC’s Division of Nutrition, Physical Activity and Obesity, said obesity was a major risk factor for several chronic ailments such as heart disease and diabetes.

“As obesity increases among all age groups, we are seeing chronic diseases in much younger adults compared to a few decades ago,” Dietz said. “For example, we now see young adults who suffer from heart-disease risk factors and other conditions such as Type 2 diabetes that were unheard of in the past.”

The McClatchy-Ipsos survey found that 75 percent of Americans think the most effective way to combat obesity is through education about the importance of exercise and a healthy diet, but so far, apparently, the CDC’s education efforts are falling short.