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Americans Getting Even Fatter

Big weight gains noted among men, children since 2000, studies find

TUESDAY, April 4, 2006 (HealthDay News) -- There's disturbing, yet hopeful, news from two reports that document America's obesity epidemic.

The bad news is that rates of overweight and obesity continue to rise, particularly among men and children, some as young as 2 years old. The good news is that reducing caloric intake might help reverse some of the damage done by excess weight, possibly in as little as six months.

The studies, from researchers at the U.S. Centers for Disease Control and Prevention, appear in the April 5 issue of the Journal of the American Medical Association.

What's particularly alarming is that one of the biggest increases in overweight and obesity was seen in children. The researchers found that 17.1 percent of kids were overweight in 2004, compared to 13.9 percent in 2000. Even the youngest children weren't immune to this trend. In children between 2 and 5 years old, 13.9 percent were overweight in 2004, compared to 10.3 percent in 2000.

The report also found the incidence of obesity among men was up to 31.1 percent in 2004, vs. 27.5 percent in 2000.

The second study reported on a trial of calorie restriction in a small group of overweight individuals. After six months on a calorie-restricted diet, two biomarkers indicating longevity -- fasting insulin levels and lower body temperature -- improved.

"Diet and exercise are key factors in preventing chronic diseases and delaying aging," said Dr. Luigi Fontana, an assistant professor of medicine at Washington University School of Medicine in St. Louis, and an investigator at the Italian National Institute of Health, in Rome.

"These studies strongly support the need to educate people to make sensible choices when they eat and that they need to exercise and walk more, instead of going by car everywhere," said Fontana, who wrote an editorial accompanying the studies.

Fontana recently published his own study, in the January issue of the Journal of the American College of Cardiology, which found that when people were on a lower-calorie diet that was nutritionally balanced -- providing 100 percent of the U.S. recommended daily allowances of vitamins and minerals -- their heart function was similar to a person 15 years younger.

"This suggests that cardiovascular disease is totally preventable by diet and that you can possibly prevent aging with [a nutritionally sound] diet," he noted.

The CDC reports analyzed the height and weight measurements of 3,958 children between the ages of 2 and 19, as well as 4,431 adults older than 20.

In children, overweight was defined as having a body mass index (BMI) above the 95th percentile for that age and sex category. In adults, a BMI between 18.5 and 24.9 is considered normal, 25 to 29.9 is overweight, above 30 is considered obese, and over 40 is extremely obese, according to the CDC.

The new research reported on data from 2003 to 2004. The researchers found that 17.1 percent of children were overweight, and 66.3 percent of adults were overweight. Just over 32 percent of adults were obese, with 4.8 percent considered extremely obese.

The rates of overweight and obesity went up significantly in children and in men. However, there were no significant increases in obesity in women between 1999-2000 and 2003-2004.

In the second study, Louisiana researchers looked at the effect of calorie restriction in a group of 48 overweight men and women. Their average age was about 38.

They were randomly assigned to one of four groups: "control," or weight maintenance; a 25 percent reduction in baseline calorie intake; 12.5 percent calorie reduction plus exercise equivalent to an additional 12.5 percent calories burned, or to very low-calorie diet of about 900 calories a day.

All of the calorie-restricted groups lost at least 10 percent of their initial body weight during the six-month study. The calorie restriction resulted in decreased fasting insulin levels and decreased body temperature, which may be considered potential signs of longevity, according to the study authors.

The researchers also found a reduction in DNA fragmentation, which suggests that less DNA damage was occurring in the groups that aren't consuming as many calories. The study authors concluded that longer-term studies are needed to see if calorie restriction can actually affect the aging process.

Nutritionist Samantha Heller, of New York University Medical Center, said she wasn't surprised by the findings from either study, and cautioned that people who restrict their caloric intake still need to be concerned about good nutrition.

"There tends to be a real disconnect in people's minds between cutting back on calories and being healthy," said Heller. She said people should concentrate on eating healthful foods first, and then cut back on calories. That's because it's possible to cut calories, but still eat junk food, she explained.

More information

To calculate your BMI, visit the U.S. Centers for Disease Control and Prevention.

SOURCES: Luigi Fontana, M.D., Ph.D., assistant professor, medicine, Washington University School of Medicine, St. Louis, and investigator, Italian National Institute of Health, Rome; Samantha Heller, M.S., R.D., senior clinical nutritionist, New York University Medical Center, New York City; April 5, 2006, Journal of the American Medical Association
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