The large percentages of children in developed countries who are overweight or obese continues to worry public health experts. “Eating too much” is not a sufficient answer. Sedentary habits -- hours spent on telly or other screen-based pastimes -- are contributing factors. But family structure matters too.
An Australian study has found that girls in single-parent families are more at risk of obesity than children in two-parent families. “This fits with recent research findings from the United States showing that children in single-parent households are at a higher risk of becoming overweight or obese than those from households with two parents,” says the author, Linda Byrne.

Our research indicates that children in single-parent households eat fewer servings of fresh fruit and vegetables, eat more servings of food high in fat and sugar, and spend an extra two hours every week watching television, compared with children in dual-parent families.

The difference in servings per day is relatively small, about half a serve less of fruit and veges, and half a serve more of food high in fat and sugar, but clearly this, combined with increased sedentary behaviour, such as watching television, is having a cumulative effect. What to do about that? Ms Byrne quite rightly does not want to blame single mums for using TV as a baby-sitter and being “guilted” into buying the high-fat/salt/sugar snack foods their children crave. Their lives are hard enough. What they need is information -- small changes can have an effect -- and support.
As a psychologist and lecturer, however, she could use her influence to inform young people about the benefits (and they include much, much more than weight control) for children of having both a mum and dad at home, and support social policy that encourages marriage. Maybe she does that already. Let’s hope.
But why girls in this study and not boys? US research shows they are equally at risk.

It may be that girls are less active than boys, or environmental factors could be at play.

Mothers' perception of neighbourhood safety has been found to predict higher weight in daughters. If single mums think their neighbourhood is unsafe, they may be less likely to encourage their daughters to go outside to exercise. A British study in 2009 found that overweight and obesity ran on gender lines within families, with girls 10 times more likely to be overweight if their mothers were too. This was attributed to role modelling rather than some genetic predisposition.
I seem to recall, also, research that shows the absence of her father has particular risks for a girl growing up. This could be one of them.