A new ‘obesity’ gene test may detect babies at risk before their first birthday. Cambridge University researchers are developing a genetic test that will identify children destined to pile on the pounds early in life.

They hope to prevent children putting on weight, which makes them more likely to suffer heart disease and diabetes.

Doctors have known for some time that there is a link between a baby’s size at birth and the chances of developing certain illnesses many years later.

The latest research shows that small babies who quickly catch up in size and who are also born with the “insulin gene” - the gene that has been linked with problems dealing with insulin in later life - may be at greatest risk of developing diabetes and heart problems.

Increased risk of disease

Researcher Dr Ken Ong said: “We have found that measurement of very early growth, combined with genetic testing, can predict which babies will grow into heavier, fatter children - those with increased risk of disease in later life.

“If we can predict this by the age of one - with a combination of growth charts and genetics tests - we could do something about it early on, rather than wait until they have a weight problem as older children.”

Doctors would be able to tell the parents of toddlers about the risk and give dietary and exercise advice that could help them avoid future illness, he added.

Obesity is increasing dramatically in both children and adults in the UK, with the number of overweight and obese children doubling since 1982.

It is estimated that one in ten six-year-olds is obese, rising to 17 per cent of 15-year-olds. Surveys of children in the 1970s found little change in their weight, but the “fat kids” problem has exploded since the 1990s.

Obesity epidemic fears

It is feared that children are becoming victims of an obesity epidemic fuelled by junk food diets and sedentary lifestyles that could condemn them to years of ill-health and an early death.

The latest research, published in the medical journal Diabetes, involved more than 1,000 children who are part of the 90s study (also known as the Avon Longitudinal Study of Parents and Children) based at Bristol University.

The researchers investigated children who were of low birth-weight to begin with but went on to catch up in size by the age of two _ an early growth pattern typical of first-born children.

Fat infants

Measurements showed those early catch-up infants tended to become children who were taller, heavier and fatter by the age of eight.

Dr Ong said: “We previously identified the first gene variant - in the insulin gene - related to common differences in birth size and we have since done a number of further studies to confirm that this genetic finding is true.”

This insulin gene variant - detected by a simple blood test - also appears to affect childhood growth rates, said Dr Ong.

Doctors might be able to screen all early catch-up infants for the insulin gene variant, so that children who are at greater risk of developing diabetes or heart disease could be advised on lifestyle changes to avoid falling ill, he added.