Teenagers who eat a lot of fiber-rich foods, such as vegetables and whole grains, are less likely to have risk factors for diabetes and heart disease, a new study shows.

But there was no link between those risk factors - known collectively as metabolic syndrome - and how much saturated fat or cholesterol kids ate.

That doesn’t give teens the green light to chow down on fatty foods, however, said Joe Carlson, who heads the Division of Sports and Cardiovascular Nutrition at Michigan State University in East Lansing.

“We know if you eat a lot of saturated fat, or trans fat, it tends to raise (bad) cholesterol and total cholesterol,” Carlson, who worked on the new study, told Reuters Health.

Instead, he said, it’s better to aim for diet rich in fruit, vegetables and whole grains.

Carlson and his colleagues examined the diets of over 2,000 U.S. teens ages 12 to 19. They also tested whether the teens had three or more conditions that make up metabolic syndrome: high blood pressure, elevated levels of sugar and fats in the blood, low levels of HDL or “good” cholesterol and a large waistline.

“There has been quite a lot done on the link between exercise and metabolic syndrome, but not nutrition,” said Carlson.

Overall, about six percent of the teens had metabolic syndrome. Of those who ate the least fiber (less than three grams per 1,000 calories), nine percent had the risk factors, compared to only three percent of those who ate the most (11 grams or more per 1,000 calories).

Carlson told Reuters Health it’s important to know that metabolic syndrome is not a disease, but a suite of measurements that put people at higher risk down the road.

“It’s a warning,” said Carlson.

Nearly 26 million Americans have diabetes, and more than 600,000 die of heart disease every year, according to the Centers for Disease Control and Prevention.

While the study can’t prove that fiber itself was responsible for that difference, the findings resonate with current dietary guidelines. Carlson said a good goal is to get three servings of fruit, three servings of vegetables and two servings of whole grains a day.

Dr. Larry Deeb, past-president of the American Diabetes Association, Medicine & Science, added that people should steer clear of highly processed foods, which often have low fiber content.

“If you ask me what you should eat, it should be something that was in the ground or something that was running around,” he told Reuters Health. “Not too much of the processed stuff.”

The study is based on government data collected between 1999 and 2002 for the National Health and Nutrition Examination Survey.

SOURCE: Journal of the American Dietetic Association, November 2011.