With Michelle Obama heading up a new anti-obesity programme in the United States studies analysing the problem of childhood obesity are coming thick and fast.

Few of them contain any surprises to a person of average intelligence -- like the discovery by Ohio State University researchers that four-year-olds who ate dinner with their siblings and parents, got a lot of sleep and had their TV viewing rationed were almost 40 per cent less likely to be obese than those from less disciplined households.

My guess is that family dinners generally mean a balanced diet and good family relationships -- so less compensatory eating, for one thing. A good long sleep means plenty of energy for the mental, physical and social tasks of the day. And all of that means not much time for lolling about in front of the TV, with its constant invitations to eat more.

“The routines were protective even among groups that typically have a high risk for obesity,” says lead researcher Dr Sarah Anderson. That includes children whose mothers are severely overweight, whose household income is below the poverty level, and whose mothers left school early.

Dr Anderson could not say whether one of the three routines was the most important -- the more the merrier, basically. But her study did show which was the most difficult to implement:

More than 56 per cent of families had dinner together at least six evenings per week, and in 57.5 per cent of cases pre-schoolers slept at least 10.5 hours per night.

TV time was limited to two hours or less among 40.4 per cent of families.