You don't have to read a scientific study to guess many kids don't eat right or get enough exercise. You might be surprised to learn, however, just how prevalent these unhealthy behaviors are in America's children and teens.

Researchers assessed four areas of health behavior in about 900 kids between ages 11 and 15. They found nearly 80 percent of the kids fell short in at least two areas. About half were deficient in three areas of health behavior, and just 2 percent passed the grade for all four.

University of California, San Diego, investigators looked at physical activity, television viewing time, percentage of calories coming from fat and number of daily servings of fruits and vegetables. Overall, about 30 percent of the kids were watching too much TV, and only 32 percent were limiting fat intake to appropriate levels. Approximately 12 percent were eating their fruits and vegetables. About 45 percent were getting the right amount of exercise.

Researchers also assessed the children's parents for these health behaviors to see how far the apple might be falling from the tree. They report girls were less likely to have risky health behaviors if their parents didn't smoke and ate enough fruits and vegetables. Parental behaviors were associated with less risky behaviors in boys as well, although the connection was not as strong.

Gender also made a difference in the physical activity scores, with nearly 60 percent of boys getting enough exercise compared to only about 33 percent of girls. Boys and girls with more risky behaviors were also more likely to be older and either overweight or at risk of becoming overweight.

Source: American Journal of Preventive Medicine