Obesity Is Going to Extremes, Study Reports

Americans are not just getting fatter, they are ballooning to extremely obese proportions at an alarming rate, a study reported Monday.

The number of extremely obese American adults -- those who are at least 100 pounds overweight -- has quadrupled since the 1980s to about 4 million. That works out to about 1 in every 50 adults.

Extreme obesity once was thought to be a rare, distinct condition whose prevalence remained relatively steady over time. The new study contradicts that thinking and suggests that extreme obesity is at least partly due to the same kinds of behavior -- overeating and under-activity -- that have contributed to the epidemic number of Americans with less severe weight problems.

In fact, the findings by a Rand Corp. researcher show that the number of extremely obese adults has surged twice as fast as the number of less severely obese adults.

On the scale of obesity, “as the whole population shifts [toward greater weight gain], the extreme categories grow the fastest,” said Rand economist Roland Sturm. “These people have the highest health-care costs.”

Sturm said health problems associated with obesity -- including diabetes, heart disease, high blood pressure and arthritis -- probably affect the extremely obese disproportionately and at young ages.

Sturm analyzed annual telephone surveys conducted nationwide by the national Centers for Disease Control and Prevention. His report covers surveys from 1986 through 2000. The findings appear in Monday’s Archives of Internal Medicine.

In 1986, 1 in 200 adults reported height and weight measurements reflecting extreme obesity, or a body-mass index of at least 40. By 2000 that had jumped to 1 in 50, Sturm found.

The prevalence of the most extreme obesity -- people with a body-mass index of at least 50 -- grew from 1 in 2,000 to 1 in 400, Sturm said.

By contrast, ordinary obesity -- a body-mass index of 30 to 35 -- doubled, from about 1 in 10 to 1 in 5, based on the same surveys.

Americans tend to understate their weight, and a recent study based on actual measurements found an obesity rate of nearly 1 in 3, or almost 59 million people. Sturm said his findings probably understate the problem for the same reason.

The average man with a body-mass index of 40 in Sturm’s study was 5-foot-10 and 300 pounds, while the average woman with the same body mass was 5-foot-4 and 250 pounds.

Dr. Mary Vernon, a trustee of the American Society of Bariatric Physicians, said the study reflects what doctors who specialize in treating obesity are seeing in their offices.

Vernon said the number of her patients weighing 300 to 350 pounds or so has doubled in the last several years.

She said thinking has evolved from a generation ago, when many doctors believed extreme obesity was due to hormonal abnormalities or other distinct conditions.

Now many believe it is a combination of lifestyle factors and genetics, as well as a propensity for some people’s bodies to be hyper-efficient at storing calories. This tendency would benefit people in societies where starvation is rampant but is a problem in developed countries where food is plentiful and lifestyles are increasingly sedentary, Vernon said.