For the first time, the Centers for Disease Control and Prevention has sent a team of specialists into a state, West Virginia, to study an outbreak of obesity in the same way it studies an outbreak of an infectious disease.
"We were looking at our data," Ms. Kennedy said, and saw that "we are facing a severe health crisis."
The state ranked third in the nation for obesity - 27.6 percent of its adults were obese, compared with 20.4 percent in the country as a whole. And, Ms. Kennedy said, "our rate of obesity appears to be increasing faster than the rest of the nation."
Going along with the obesity was a high prevalence of diabetes and high blood pressure, which are associated with extra pounds. West Virginia ranks fourth in the nation for diabetes, with 10.2 percent of the population affected, compared with 6.4 percent nationwide. And it is No. 1 in its prevalence of high blood pressure, with 33.1 percent having the condition, compared with 25.8 percent of people nationwide.
So the state asked the agency's disease detectives to tackle its obesity problem, and a three-week investigation began on April 25. It focused, Ms. Kennedy said, on two places that represented towns and cities in the state - Gilmer County, with 7,160 residents, and Clarksburg, a city with 16,743 residents.
The investigative teams spent a week and a half in each place, going to schools and asking about physical education programs and about what sort of food was provided. They asked, for example, whether students "were offered at least one or two appealing fruits and vegetables every day," Ms. Kennedy said. And "would you replace regular sour cream with low-fat sour cream?"
They went to workplaces, asking whether there were policies to encourage physical activity. For example, Ms. Kennedy said, "if you choose to walk, could you have an extra 15 or 20 minutes added to your lunch break?" And, were there items like 100-percent fruit juices and bottled water in vending machines?
They went to random grocery stores and restaurants, asking whether they offered fruits and vegetables and skim or 1 percent milk. And they asked whether it was safe to walk along the roads, whether there were sidewalks and whether they were in good repair, whether there was good lighting for walking at night.
"The C.D.C. came up with the questions for us," Ms. Kennedy said. But, she noted, many of the questions, like the ones about sidewalks, were designed for urban areas. She said she was not sure how well they would work in rural West Virginia, and some statisticians said they did not think the study would work at all.
Dr. Julie Gerberding, the director of the disease centers, said in a press conference yesterday that this type of investigation was a first for the agency.
"This has never happened in the history of the C.D.C," she said.
The centers held the news conference to clarify its position on weight and obesity. Agency scientists recently published a study concluding that overweight people had a lower risk of death than normal-weight people and that even obese people did not have much of a risk of early death unless they were extremely obese. A year earlier, different researchers at the agency published a study saying that obesity and extra weight were markedly raising death rates in this country.
Obese people were defined as having a body mass index, a measurement of weight in relation to height, of 30 to 34.9; the extremely obese had an index of 35 or higher.
Dr. Gerberding said that there were still questions about the best ways to estimate death risks from extra weight but that there was no question about the health impacts of being obese or overweight, which can increase the risk of diseases like diabetes, high blood pressure, arthritis and some cancers. Being obese or overweight, Dr. Gerberding emphasized, are "critically important health threats" and the agency is increasing efforts to understand the causes of the obesity epidemic and how to help people lose weight and keep it off.
The West Virginia data are now at the agency, being analyzed. Some preliminary information may be available in August, Ms. Kennedy said.
Rudy Philips, a 27-year-old clinical nursing assistant who lives in Clarksburg, said that he was unaware of the study, but that he knew something of the dietary problems in the state. He himself had a good diet, he said, and while "I could stand to lose 5 or 10 pounds, I am not obese." But obesity is a problem in the state, he observed.
"We tend to eat a lot of fried foods, we're meat-and potatoes type people," Mr. Philips said. "Most restaurants don't have healthy choices."
But some statisticians said it was hard to see what could be learned from the agency's investigations.
Daniel McGee, a professor of statistics at Florida State University who has analyzed obesity data, burst out laughing when he heard about it. "My God, what a strange thing to do," he said.
"They'll find out what we all know - that the country is no longer set up for physical exercise," Dr. McGee said. And that schoolchildren "don't get a nutritious diet." And that "there is a lot of high-fat food on the shelves of every supermarket."
But, he said, "that doesn't tell you much."
"I'm sure skinny people go to those same restaurants," Dr. McGee said. "Skinny kids go to those same schools."
David DeMets, a professor of biostatistics at the University of Wisconsin, was also extremely skeptical.
"We get a lot of false positives from that kind of investigation," Dr. DeMets said. "We get people worried," but there is no way to know whether what is found - a lack of fruits and vegetables in the schools, for example - has anything to do with the obesity epidemic.
"Perhaps it is true, perhaps it is not," Dr. De Mets said.