Overweight women may have their mums to blame

Daughters of overweight mothers are at greater risk of being overweight, a study has found.

Mothers have huge influence over how much their children run around during the day and what they eat, so those who are sedentary and have a less healthy diet can pass these habits on.

If mothers were overweight or did not have a healthy diet in pregnancy, evidence suggests they could also have ‘programmed’ their child in the womb to be biologically more at risk of obesity.

But now new research suggests these factors only affect daughters, and not sons.

Researchers looked at 240 children, whose body mass index (BMI) and fat mass was measured in three visits, when they were aged four, aged six to seven, and eight to nine years old.

Their mothers and fathers had the same measurements taken at the third visit.

Fathers’ weight and body fat level was not linked to those of their children.

But the more overweight a mother was, the more overweight her daughter tended to be at ages six or seven and eight or nine.

Sons may not be affected in the same ways as daughters by their mothers’ obesity because boys are typically more active in childhood and burn off more calories than girls.

A more important factor is likely be that girls are more influenced by what happens to them in the womb if their mother is overweight.

Women’s fat mass was also linked to the fat mass of their daughters at age six and seven and eight or nine.

The study concludes that overweight mothers should be aware of possible effects on their daughters, and perhaps try to reach a healthy weight before falling pregnant.

Dr Rebecca Moon, from the MRC Lifecourse Epidemiology Centre at the University of Southampton, said: ‘These findings suggest that girls born to overweight mothers are at high risk of themselves becoming overweight, which does not seem to be the case in boys.

‘We need to do further research to understand why, in terms of families’ diet and exercise patterns, and how female foetuses respond in the womb to what women eat during pregnancy.

‘This also provides an opportunity to identify young girls who may be at higher risk of developing overweight or obesity, so that we can address this early in childhood.’

Previous studies have found overweight mothers are more likely to have overweight children, but did not typically look at the difference between girls and boys.

The new study not only looked at girls and boys separately, but analysed children’s body measurements at three ages, to capture the changes in children’s fat level, which tends to increase more rapidly from the age of six.

Researchers scanned people’s body fat as well as calculating their BMI for greater accuracy, as BMI can make toned people, whose muscle is heavy, seem as if they are overweight.

Women’s BMI and body fat was not linked to their sons’ BMI or body fat at any age, based on the data, which was gathered from a health survey carried out in the Southampton area.

But there was a link between women and their daughters’ BMI and body fat at older ages, which matters because children who are overweight are more likely to become overweight adults, with a greater risk of health problems like type 2 diabetes, high blood pressure and heart problems.

If women can maintain a healthy weight before they get pregnant, and keep their young children active and eating well, this may help to protect their daughters.

The study is published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.