That's because in children who have a genetic predisposition to gaining extra weight, parental restriction of food may actually cause them to gain more weight, says a study appearing in the October issue of Pediatrics.

"There's a lot of controversy because some studies have found a relationship between more restrictive feeding style and heavier kids," said study co-author Myles Faith, of from the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine.

"It's the chicken and the egg question. Is it the parent's restrictiveness causing the child not to know when he's hungry or full, or is it that a parent sees an overweight child and decides to restrict what he's eating?" asked Myles Faith, of from the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine. "Or could it be both?"

In this study, the researchers found that restricted eating was really only a problem in children whose mothers were overweight at the start of their pregnancy, which Faith said is a good indicator of a child's genetic risk for being overweight.

He added, though, that parents are probably restricting food, in part, as a response to their child's increasing weight.

"It might be a bi-directional relationship, because parents don't behave in a vacuum. They respond to children's behaviors and characteristics. The concern, though, may be excessive restriction," said Faith.

Faith and his colleagues studied 57 families to see how parental feeding styles affected the child's weight. The children were classified as either high risk or low risk for obesity based on their mothers' weight. Their weight and height measurements were taken at ages 3, 5 and 7 so that their body mass index (BMI) could be calculated.

Parents were given a questionnaire designed to identify their feeding styles and attitudes when their children were 5, and then again when the kids were 7.

The researchers found that parents' feeding styles didn't change much during the two-year study period. More importantly, they found differences between high-risk and low-risk children in the way they responded to parental feeding styles.

High-risk children were much more likely to have an increased BMI at the end of the study if their parents restricted food. The authors suggest this shows a relationship between genes and the environment when it comes to obesity.

Faith suggests that, rather than excessively restricting foods, parents should actively promote healthy food choices, make healthy food available, and model good eating behavior themselves.