Parents who think their teenagers are overweight are no more likely to banish junk food and keep healthful foods around the house than those who don’t – or to encourage habits such as family meals, less eating in front of the tube and more exercise. But they are more likely to urge their teen to diet. The study, conducted by researchers at the University of Minnesota and published this month in Pediatrics, was part of a larger one gauging the weight and eating habits of 902 Minneapolis-St. Paul adolescents through interviews with the mother or primary caregiver. Five years later, the project returned to 314 parents who had accurately identified their child as overweight – and found that encouragement to diet was counterproductive. Teens who had been thus encouraged were more likely to be overweight than those who were not.

Study lead author Dianne Neumark-Sztainer, a University of Minnesota professor, said the findings are in line with others showing that efforts to restrict a child’s dietary intake can backfire. With adolescents, she added, the “fine line” between helpful and harmful parental influence regarding weight is probably even trickier to negotiate.