Pundits often opine that America's stature is declining on the global stage. It turns out that Americans - literally - are not standing as tall, compared with the rest of the world, as they used to.

U.S. adults lost their position as the tallest people on Earth to the Dutch, who average about 2 inches taller than the typical American. In fact, American men now rank ninth and women 15th in average height, having fallen short of many other European nations.

"Americans, who have been the tallest in the world for a very long time, are no longer the tallest," said John Komlos of the University of Munich, who has published a series of papers documenting the trend. "Americans have not kept up with western European populations."

The idea that many Europeans are looking down on Americans has led to a flurry of interest in trying to explain the trend, with debate focusing on whether to blame the lack of universal health care and other holes in the nation's social safety net, particularly for children.

"We conjecture that perhaps the western and northern European welfare states, with their universal socioeconomic safety nets, are able to provide a higher biological standard of living to their children and youth than the more free-market-oriented U.S. economy," Komlos wrote in one of his latest papers, published in June in the journal Social Science Quarterly.

While some researchers agree, others are more cautious, arguing that height is determined by a complicated amalgam of genetic, environmental, social and biological influences.

"It's a puzzle to which we really don't have a good answer at this point," said Robert Fogel of the University of Chicago Graduate School of Business. "Nobody has identified anything that can really explain it."

Nourished by a bountiful food supply and free from scourges that plagued Europe, Americans quickly became the tallest people in the world. The colonists were about 2 inches taller than the British they defeated in the Revolutionary War, and Americans towered about 3 inches above the average Dutch and other Europeans by the 1850s. That trend prevailed for two centuries through both world wars as America's wealth and influence paralleled its dominant height around the globe.

But in a series of papers, including his most comprehensive work to date - the June analysis of federal surveys conducted between 1959 and 2004 - Komlos and others have shown that growth of the average American declined beginning in the 1950s, allowing other countries to overtake the United States by the 1970s. Although Americans have resumed growing in the past few decades, the rate has not kept pace with other nations.

"Americans were still growing until the Eisenhower administration and then stopped for two decades, which is odd, given the great improvement in health, in medical technology and given the great improvements in income," Komlos said. "Despite this, Americans have been surpassed by western European populations."

Komlos' most recent analysis excluded Hispanics and Asians to try to eliminate the effect of immigration. In another paper that has not yet been submitted for publication, Komlos produced similar findings examining military records that enabled him to exclude people whose parents were born elsewhere to further account for immigration. Another paper being published soon found identical trends among children - height stagnated among children in the United States for several decades beginning in the 1950s but continued to increase among Europeans.

"That explains why the western Europeans overtook the Americans," Komlos said.

Height is considered a bellwether of a society's well-being. As wealth increases, often so does height. Wealth usually improves nutrition and medical care, enabling people to reach their maximum growth potential and live longer. The key years are early childhood - with those children receiving the best nutrition and suffering the least illness growing the best.

Komlos and others noted that the contemporary American diet, while plentiful, has become less nutritious.

"The culture of food here is different than other countries," said Richard Steckel of Ohio State University. "Children tend to watch more television and snack and eat fast food. When they do this, the fuel they are consuming is not the optimal blend."

© 2007 Hearst Communications Inc.