Parents – especially those of overweight children – give schools a failing grade for efforts to encourage healthy habits that combat childhood obesity, according to a new poll from the University of Michigan. “Children do spend much of their time at school, so it is important that they receive health messages about nutrition and physical activity during the school day,” says Dr. Matthew M. Davis, professor of health management and policy at the University of Michigan School of Public Health and professor of pediatrics at U-M Medical School.