ATLANTIC CITY, New Jersey (AP) - Miss America is getting skinnier and skinnier.

Using the heights and weights from most of the winners in the pageant's 78-year history, nutrition experts from Johns Hopkins School of Public Health concluded that many are in the undernourished range.

The research was published in Wednesday's Journal of the American Medical Association.

Dr. Benjamin Caballero, director of the Center for Human Nutrition at Johns Hopkins, said pageant officials should screen out contestants who are too skinny in order to "promote a message of healthiness."

"The actual influence of pageant competitions on young women's decisions about diet and lifestyle is not well-documented," he wrote, "but it is likely to have a strong, if indirect, effect."

The researchers used the height and weight figures to calculate a measure, called body mass index, and concluded that it has generally fallen over the years. BMI is weight divided by the square of height.

In the 1920s, contestants had BMIs in the range now considered normal, which is 20 to 25, the researchers said. But an increasing number of winners since then have had BMIs under 18.5, which is the World Health Organization's standard for undernutrition.

The highest index was 22.4 for Miss America 1941, Rosemary LaPlanche; the lowest, 16.9, for Miss America 1986 Susan Akin.

The medical journal did not publish the heights and weights of the winners.

The lightest Miss America, according to The Press of Atlantic City newspaper archives, was also the first - 1921's Margaret Gorman, who weighed 108 pounds (48.6 kilograms). The heaviest was Miss America 1952 Colleen Kay Hutchins, who weighed 143 pounds (64.35 kilograms).

Pageant winners, like the rest of the U.S. population, have gotten progressively taller. But that doesn't explain the thinning of Miss America, the researchers said. Pageant winners' height increased less than 2 percent, but body weight decreased 12 percent.

However, Robert M. Renneisen, Jr., chief executive of the Miss America Organization, said recent winners have had some of the highest body mass readings, a reflection of pageant officials' emphasizing brains over beauty.

The swimsuit competition counts for only 10 percent of the total score, he said.

"We long ago made the change from more superficial to more substantial criteria," Renneisen said. "We're seeing that, not only in the caliber of the young women competing but the very data they show here, which shows that from 1986, even physically, the kind of person is changing."

One eating disorders expert said the report substantiates what he has suspected all along.

"Beauty pageants, like the rest of our media-driven culture, give young women in particular a message, over and over again, that it's exceedingly important to be thin to be considered successful and attractive," said Dr. Harry Brandt, director of the Center for Eating Disorders at St. Joseph Medical Center in Towson, Maryland.

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