Kids Who Eat Too Much Fat, or Too Little, Prone to Weight Gain

And too many aren't eating enough dairy products, study finds

THURSDAY, March 4, 2004 (HealthDayNews) -- Children who eat very high levels of fat or very low levels of fat, as well as those with a low intake of dairy products, gain more weight than kids who eat moderate amounts of fat.

That's the conclusion of a new study by researchers at Boston University, who will present their findings March 4 at the American Heart Association's Annual Conference on Cardiovascular Disease, Epidemiology and Prevention in San Francisco.

This is just the latest in a long line of research pointing to the dangerous dietary habits of American kids, health experts say.

"This is a multifactorial problem that's escalating in an alarming way and creating an epidemic [of obesity]," says Dr. George Fielding, a bariatric surgeon and specialist in adolescent obesity at New York University's Surgical Weight Loss Program in New York City. "The changes in the last 10 years have been frightening."

Among those changes are kids eating more fast food and, in particular, more super-sized fast foods. Instead of drinking one can of soda, kids are drinking 2 liters. Also, Fielding adds, "there's data showing that 25 percent of all the food that children in Australia and the U.S. eat is snack food and there's nothing good in it."

"If they're getting 25 percent of their food this way, they are just drowning in calories," Fielding adds. The average 12-year-old needs about 1,500 calories a day, while the average consumption in the United States is about 3,600, he says.

In addition, many fast foods and snack foods don't make you feel full, Fielding adds.

There's another aspect to the equation -- children are getting less exercise. "You have to walk for 45 minutes to walk off one can of Coke," Fielding says. "Kids are being squeezed on all fronts."

The new study, part of the Framingham Children's Study, analyzed the dietary habits of 106 families who had one child 3 to 5 years old at the start of the study. The children kept "food diaries" with detailed descriptions of foods, portions, brands and recipes consumed over a 12-year period until the participants were adolescents. The diaries were analyzed and then cross-tabulated with excessive gains in body fat during that period.

Children for whom fat represented at least 35 percent of calories, as well as those whose diets were less than 30 percent fat, gained more weight than those who took in moderate amounts of fat -- meaning 30 percent to 35 percent of calories.

By early adolescence, children with high-fat diets had an average skinfold measurement of 104.6 millimeters of body fat, while those with low-fat diets had an average skinfold measurement of 92.2 millimeters. Those with more moderate diets had a more reasonable 74.7 millimeters of body fat.

Furthermore, children with the lowest consumption of dairy products (less than one-and-one-quarter servings per day for girls and less than one-and-three-quarter servings per day for boys) gained the most weight -- about three millimeters more skinfold fat each year -- than children in the other two groups. And children who ate more fruits and vegetables gained less fat.

While people who eat less fat often compensate by eating more carbohydrates, this does not appear to have been a factor among these children, says study author Lynn Moore, director of the Framingham Children's Study and an associate professor of medicine at Boston University School of Medicine.

Rather, she says, lower consumption of dairy products, such as milk, seems to have been the culprit.

"One thing that does stand out about low-fat diets is that there was a lower intake of dairy," Moore says. "In this study, the strongest factor for excess body fat gain between preschool and adolescence was dairy intake In many cases, sodas have replaced dairy in the American diet."

There may be several different mechanisms at play here. "It may be linked at the intracellular level to how fat is stored," Moore postulates. There may also be other compounds in dairy that affect how weight is regulated and how glucose is metabolized. Dairy may also help kids feel full so they don't eat as much.

People may be consuming less dairy because they erroneously equate it with too much fat, which is not necessarily the case, especially if you opt for low-fat or skim milk, Moore says.

More information

For more on children's nutrition, visit the USDA/ARS Children's Nutrition Center at Baylor College of Medicine. For more on childhood obesity, visit the American Obesity Association.

SOURCES: Lynn Moore, D.Sc., associate professor, medicine, Boston University School of Medicine; George Fielding, M.D., bariatric surgeon and specialist, adolescent obesity, Surgical Weight Loss Program, New York University, and associate professor, surgery, New York University School of Medicine, New York City; March 4, 2004, presentation, American Heart Association Annual Conference on Cardiovascular Disease, Epidemiology and Prevention, San Francisco
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