Researchers aren't sure whether the exercise was the only factor, but the BMIs of the children with TV bikes dropped from an average 30.2 to 29.9, while in the control group, the BMIs rose, from 26 to 27. Total percentage of body fat in the TV bike group dropped from 44.5 to 43.3 percent, while the percentage of fat in the control group rose from 37.1 to 38 percent, Faith says. The study admittedly didn't cover all the bases. The children may have been physically active when they weren't watching television, and the researchers said they didn't really know what the kids were doing with their extra time. Increasing activity and decreasing sedentary activity are critical when you're fighting obesity, says Dr. Stephen Daniels, a professor of pediatrics at the University of Cincinnati College of Medicine and Children's Hospital Medical Center.
Television watching is one of the big sinks of sedentary time.
But the study does point to another useful fact, Daniels adds. When you make television watching too costly to kids, kids will choose not to watch. Parents can balance kids' lives more by offering television rewards in exchange for taking part in physical activity, he says. For more on children and obesity, try KidSource . You can read more about children and obesity, including recent stories about how drinking too much soda can add weight to kids, at HealthScout .