Changing the way that parents interact with their infants could help combat child obesity, a US study suggests.
New mothers were offered ways of responding to babies' needs, including avoiding comforting with food.
By the age of three, children exposed to so-called "responsive parenting" had lower body mass index (BMI).
A UK child health expert said the study showed a small, early intervention could have long-term benefit.
Eating and sleeping behaviours are established early.
And if food is used to soothe or reward in infants, rather than just when they are hungry, that child may then use food to soothe their distress in later life and it could lead to them being obese.
In the study, published in the Journal of the American Medical Association (JAMA), nurses advised 279 first-time mothers – in their homes in the first six months after birth, and at a clinic at one and two years – on how to respond to their child's needs.
The team focused on mothers because they tend to have the leading role in caring for infants in their first months and years,
The advice included instructions on:
- sleep routines
- alternatives to feeding for calming a fussy infant
- recognising signals from the child of being hungry or full
- focusing on physical activities
The children were then checked at the age of three. Those whose mothers had been coached in responsive parenting techniques were found to have lower BMIs. Girls were affected more than boys by the intervention.
Researchers will continue to monitor them up to the age of nine.
Ian Paul, from Penn State University, who led the study, said it was about coaching the mother to "recognise their child's cues and needs", and respond with a "developmentally appropriate response in a prompt fashion".
"With such high rates [of obesity] already among toddlers, it made sense during such a developmentally important time of infancy to begin to establish healthy behaviours.
"Based on our growth charts, 20-25% of two- to five-year-olds are already overweight or obese. It's a major problem, a tough nut to crack.
"Children who are overweight or obese at an early age have a much increased risk of staying overweight or obese as they get older."
But a "lifelong approach" was needed to break the obesity cycle.
"Overweight children become overweight parents who have overweight children … so where in the cycle do you intervene?
"In our current environment, there needs to be a lifelong approach".
Figures in the UK show a similar problem.
Nearly a quarter of children in England are obese or overweight by the time they start primary school and a third by the time they leave aged 11.
Prof Neena Modi, president of the Royal College of Paediatrics and Child Health (RCPCH), said: "This shows that you can achieve small but sustained impact from an intervention that starts early in infancy, and that the effect carries through to three years.
"The real question for policy makers is what can you do to sustain this?
"We know that the power of an early intervention is going to decline with time.
"How can we reinforce the good beginning?"
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