Female parents who keep their careers on the go are more likely to drive their kids to school, give them fizzy drinks and let them watch too much TV, researchers have found.

Scientists from the Institute of Child Health called for working families to be given more support, and said governments should introduce better policies to cope with parents returning to employment.

The study of more than 12,000 families established a direct relationship between the amount of time a mother worked and the health of her children, even after socio-

economic factors had been taken into account.

Researchers questioned mothers of five-year-olds on their employment status, their children’s diet and how much exercise they took.

Fathers were excluded from the study, which will be published in the Journal of Epidemiology and Community Health.

Of the 12,576 mothers quizzed, around one-third (30%) had worked since the birth of their child, while the rest were unemployed.

Working mothers were employed for an average of 21 hours per week, and the vast majority worked between 16 and 30 hours weekly over a typical employment period of 45 months.

Survey participants answered questions on the amount of sweets, crisps, sugary drinks and fruit and vegetables they gave their children, and also on how they got to and from school.

Overall, a worrying number of children had habits that could lead to them becoming dangerously overweight in later life, the study found.

More than one-third of children mostly ate crisps or sweets between meals, and 41% of them drank sugary drinks more than they drank water.

In addition, 61% of the children whose mothers were surveyed watched television or used a computer for at least two hours on a typical day.

Once they had controlled for family income and other influential factors, the researchers found a “definite link” between the length of time a mother worked and her children’s health.

The researchers said: “Children whose mothers worked part-time or full-time were more likely than children whose mothers had never been employed to primarily drink sweetened beverages between meals, compared to other beverages; use the television or computer at least two hours daily, compared to 0-2 hours; or be driven to school, rather than walking or cycling.

“Children whose mothers worked full-time were less likely to primarily eat fruit/vegetables between meals, compared to other snacks, or to eat three or more portions of fruit daily, compared to two or fewer.”

Health officials recommend that everyone eats at least five portions of different fruits and vegetables per day, with no more than one 80g portion coming from fresh, unconcentrated fruit juice.

The researchers warned that because of the economic necessity for parents to work, the health of children was being placed at risk.

“Currently, approximately 60% of women with a child aged five or younger in the UK or USA are employed,” they said.

“For many families the only parent or both parents are working. This may limit parents’ capacity to provide their children with healthy foods and opportunities for physical activity.

“Policies and programmes are needed to help support parents and create a health-promoting environment.”

Childhood obesity has been a particular problem in Scotland, contributing to a 46% increase in medically overweight adults since 1995.

The country’s weight problem has also placed a strain on the public purse, with NHS Scotland forced to spend more than £4m in the past five years on specialist equipment to accommodate obese patients.