Children mimic parents to become obese; genes only partly to blame

Eating habits taught to children by the parent of the same gender could have a stronger influence over childhood obesity than a child's genetic makeup, according to a new study reported in the International Journal of Obesity. Researchers from the Peninsular Medical School, Plymouth, UK, showed that obese mothers were ten times more likely to have overweight daughters, while obese fathers were six times as likely to have overweight sons. The pattern was restricted to parents of the same sex as their children, suggesting that genes weren't the strongest influence.

The researchers claim that, in light of the findings, adults and not children should become the focus of government policies to prevent obesity: ‘These findings could turn our thinking on childhood obesity dramatically on its head. Money and resources have focused on children over the past decade in the belief that obese children become obese adults, and that prevention of obesity in children will solve the problem in adulthood,' Professor Terry Wilkin, who directed the study, said in a press statement.

Two hundred and twenty-sixBritish families volunteered to take part in the study, which involved having regular weight and height measurements recorded for the children and their parents over a three year period. The results showed that 41 per cent of daughters who were obese had obese mothers, compared to justfour per cent of obese daughters whose mothers were within a healthy weight range. Similarly, 18 per cent of the obese boys in the study group had obese fathers, compared to three per cent with fathers of a healthy weight.

Efforts to curtail the rise in childhood obesity, which could hurtle to as high as 90 per cent by 2050 according to current government predictions, are currently focused around the belief that overweight children grow into overweight adults. But the study's gender bias suggests that instead children are mimicking the eating habits of their mother or father, leading children of the same gender as their obese parents to become obese themselves in later life. Professor Wilkin explained: ‘Any genetic link between obese parents and their children would be indiscriminate of gender. The clearly defined gender-assortative pattern which our research has uncovered is an exciting one because it points towards behavioural factors at work in childhood obesity.'

While some severe forms of childhood obesity, such as Prader Willi syndrome, are known to be caused by mutations in a gene, obesity is generally thought to be caused by a combination of genetic predisposition and not matching daily food intake with calories burned.

Commenting in the Daily Mail, Cambridge University's Stephen O'Rahilly, Professor of Biochemistry and Medicine, said that further results would be needed before any policy changes around obesity should be considered. ‘I'm sure other groups will soon test this hypothesis in much larger numbers of families', he said, adding: 'Until this time we should treat these findings as potentially interesting but not paradigm changing.'