WASHINGTON — Americans are getting a little taller and a lot fatter.

Adults are roughly an inch taller than they were in the early 1960s, on average, and nearly 25 pounds heavier, the government reported Wednesday.

The nation's expanding waistline has been well documented, though the new report is the first to quantify that trend, based on how many pounds the average person is carrying.

The reasons are no surprise: more fast food, more television and less walking, to name a few. Researchers this year reported that obesity, aided by poor diet and lack of activity, threatens to overtake tobacco use as the leading preventable cause of death.

In 1960-62, the average man weighed 166.3 pounds. By 1999-2002, the average was 191 pounds, according to the report from the National Center for Health Statistics, part of the Centers for Disease Control and Prevention. The report said the average woman's weight rose from 140.2 pounds to 164.3 pounds.

The trends are the same for children, the report said. Average 10-year-olds weighed about 11 pounds more in 1999-2002 than they did 40 years ago. That means the next generation of adults could turn out to be even heavier, said Dr. Samuel Klein, director of the Center for Human Nutrition at Washington University School of Medicine in St. Louis.

"All the kids who are obese now will become obese adults," Klein said. "What will happen with the next generation of adults is really scary."

Obesity can increase the likelihood of diabetes, high blood pressure and high cholesterol and lead to other health problems.

The report documented an increase in weight when measured by body mass index, a scale that takes into account both height and weight. Average BMI for adults, ages 20 to 74, has increased from about 25 to 28 over the 40-year span.

Anyone with a BMI from 25 to 30 is considered overweight. Someone with a score of 30 or more is considered obese.

Although less dramatically, Americans also getting taller.

Men's average height increased from 5 feet 8 inches in the early 1960s to 5 feet 9 1/2 inches in 1999-2002.

The average height of a woman went from just over 5 feet 3 inches to 5 feet 4 inches.

Even that is a big jump in a short time, said Dr. Meir Stampfer, professor of epidemiology and nutrition at Harvard's School of Public Health.

The height trends begin in childhood and are evident through adolescence and into adulthood, said the report's author, Cynthia Ogden, an epidemiologist. Taller children grow up to be taller adults.

Height, while determined largely by genetics, also is influenced by childhood nutrition. Adults in the early 1960s grew up during tougher times when they may not have had enough to eat, Klein said.