Giving young children more physical exercise does not stop them becoming obese, a new study has shown.
The findings of researchers in Glasgow from their work with more than 500 four-year-olds run counter to the assumption that in an age dominated by television and computer games, children could slough off the pounds if they climbed more trees.
The study, published in the British Medical Journal this week, was led by John Reilly, a professor in paediatric energy metabolism at Glasgow University. His team set out to establish whether greater physical activity would prevent children from becoming overweight. They recruited 545 children in their last year at 36 nursery schools.
Half the schools instituted three extra half-hour sessions of physical play and activity every week, and parents were given information packs encouraging them to give their children more activity and less television. The other half had no extra activity or information.
All the children were regularly weighed and measured and their body mass index (BMI - the relationship between weight and height used to check for obesity) was calculated, and there was no difference between the groups.
"Despite rigorous implementation, we found no significant effect of the intervention on physical activity, sedentary behaviour or body mass index," wrote the researchers. Nor did the children show less tendency to sit about or more inclination to run around. The only positive finding was that the more active children had better motor and movement skills, which may make them more confident about doing physical activity in the future.
The study is one of the few into the prevention of obesity in children, the authors point out. Yet the problem is serious: in Scotland in 2001 at least 10% of children aged four to five and 20% of children aged 11 to 12 were obese. "Children in Scotland establish a physically inactive lifestyle before school entry," they wrote.
The study aimed to find some way to increase activity and prevent the progression to obesity before children start mainstream school. The programme was designed to be inexpensive, costing £200 and involving the training of just two members of staff at each nursery, to make it feasible if adopted at all schools. "Successful interventions to prevent obesity in early childhood may require changes not just at nursery, school and home but in the wider environment. Changes in other behaviours, including diet, may also be necessary," wrote the researchers.
The British Heart Foundation, which part-funded the study, accepted the research was solid, but said it did not mean it was not necessary to encourage children to run about and play. "It's absolutely vital for young children to be active," said Mike Knapton, its director of prevention and care. "Although this study suggests that the benefits of a small amount of extra exercise for nursery children are not visible immediately, we know it's crucial to encourage good exercise habits from an early age.
"Children get less active as they get older so it's vital that youngsters get regular physical activity to lay the foundations for good health as they grow up."
FAQ Weight debate
What's the scale of the problem?
In 2001, 10% of children aged four to five in Scotland were obese, rising to 20% of 11- and 12-year-olds. England was only slightly better: in the same year 8.5% of six-year-olds and 15% of 15-year-olds were obese.
Is there really a decline in physical activity among children?
Yes. There are substantial drops in participation in sport and walking or cycling to school, while an average child watches 2½ hours of TV a day.
Is lack of exercise to blame for children getting fat?
The food industry blames computers and the couch potato culture, but the World Health Organisation has found that high intake of foods rich in calories is a risk factor, and probably consumption of sugary drinks too.
