Last night on New Zealand television the British female lead of the live show Mamma Mia! joked about how she went to work to get away from her four young children -- a firstborn plus triplets who are on tour with her. Great for her, but how are the kids doing?

Research just published in her homeland suggests that the children of working mothers are less healthy and are more likely to have poor dietary habits and a more sedentary lifestyle. They eat less fruit and vegetables, watch more television and consume more crisps and fizzy drink than the children of mothers who stay at home.

This is bad news for British authorities, whose crowded social agenda includes fighting childhood obesity and getting women to return to work. It looks as though the two goals are at loggerheads. Flexible working arrangements for mothers in full-time work seem to make no difference, and children of part-time working mums were still not as healthy as those whose mothers stayed home. Variables such as socio-economic background, single parenthood and household income were taken into account in the results, which are based on 12,000 British children born between 2000 and 2002.

Researchers on the latest paper concluded that with approximately 60 per cent of British women with a child aged 5 or younger in employment, more support was needed. “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,” they said. “Policies and programmes are needed to help support parents and create a health-promoting environment.”

To say nothing of emotional health and character development.

Nobody, of course, is rushing to say that mothers of young children should not go out to work. The authors of the study suggest that the quality if childcare needs looking at; they are not sure whether the link they found was associated with what the kids did while the mother was at work, or with time pressure on parents when they are back in the home -- that is, whether it’s the staff at the daycare centre or the grandparents allowing bad habits, or the parents themselves being too busy and exhausted to insist on good habits.

All the same they hint that there may be something wrong at policy level:

“What policymakers need to understand is that what might be a solution to some issues may create others. There are upsides and downsides.”