An infant’s hearty appetite is traditionally seen as a healthy sign – but it could signal a predisposition to obesity, say scientists.

Babies that display two key aspects of appetite grow unusually rapidly up to the age of 15 months, which potentially increases their chances of becoming obese children, research has shown.

A second study found that ten-year-olds with a lower satiety response, making them less likely to stop eating when they feel full, were genetically more susceptible to obesity.

Satiety responsiveness (SR) was one of the measurements taken to monitor appetite in infants. Scientists studied data from non-identical same sex twins born in the UK in 2007 who had different levels of SR and food responsiveness (FR) – the urge to eat when seeing or smelling tempting food. Within pairs, the baby that was more food responsive or less satiety responsive than its twin grew faster.

At 15-months-old, both traits separately caused a twin to be around two pounds heavier than its sibling.

The findings appear in the journal JAMA Pediatrics alongside a second study by University College London’s Health Behaviour Research Centre.

Genetic data from 2,258 children aged ten was used to create scores for susceptibility to obesity. The “polygenic obesity risk” (PRS) ratings were based on the number of high-risk variants among 28 obesity-related genes in each child.

Professor Jane Wardle, from the Health Behaviour Research Centre, said: “Obesity is a major issue in child health. Identifying factors that promote or protect against weight gain could help identify targets for obesity intervention and prevention in future.

“These findings are extremely powerful because we were comparing children of the same age and same sex growing up in the same family in order to reveal the role that appetite plays in infant growth.

“It might make life easy to have a baby with a hearty appetite, but as he or she grows up, parents may need to be alert for tendencies to be somewhat over-responsive to food cues in the environment, or somewhat unresponsive to fullness. This behaviour could put them at risk of gaining weight faster than is good for him or her.”

Dr Clare Llewellyn, who led the research, said children with a higher PRS score, and likely to have a larger body mass index, are more likely to have low satiety responsiveness.

“This suggests that satiety responsiveness could be targeted for pharmacological and behavioural interventions, to prevent or treat obesity,” she said.

“For example, children with lower satiety sensitivity could be taught techniques that might improve their fullness signals when eating, such as slowing their eating speed. Another approach might be to provide better advice to parents and children about appropriate portion sizes, limiting access to ‘second helpings’ and ensuring tempting treats are out of sight between meals.”

Childhood obesity could mean storing up health problems such as heart disease, type 2 diabetes and some types of cancer in adult life. The cost to the NHS is anticipated to be just below £50 billion a year by 2050 when it is predicted that half the UK population could be obese.

In Bradford, more than 60 per cent of adults and 35 per cent of children are overweight or obese.

Doreen Ward, of Greengates, was shocked to be told her “healthy, sporty” son was overweight as a child. “He was quite well-built but enjoyed sport. As far as I was concerned he had a hearty appetite, which he burned off with exercise,” she says.

“But during a routine check-up I was told he was overweight – I couldn’t believe it. Looking back, he always continued to eat, even when he should’ve been full. I just put it down to a healthy appetite.

“He’s 18 now and has a more sensible approach to eating. It’s harder to control when they’re children. If there’s more research being done into children’s appetites, and why they eat the way they do, it is to be welcomed.

“Parents need more guidance, to help children avoid becoming obese and storing up health problems for later life.”

Professor Paul Gately, director of MoreLife, which runs children’s weight-management camps at Apperley Bridge, says what is needed is more investment in ways of tackling obesity, focusing on root causes such as psychological factors.

He wants a Government Department for Obesity. “There are 30 million adults and 4.5 million children in England with a weight problem,” he says.

“Let us have a department for obesity to start to focus on, not just watching the trends go upwards, but doing something about it.”

For more information about Bradford’s weight management programmes, call (01274) 435387.