Scientists have developed a simple blood test which they claim can predict obesity levels in children as they grow up.
Researchers in England have found that the DNA blood test, which is carried out when a child is five, can predict how much body fat they will have when they are 14.
The test checks a gene called the PGC1 that regulates fat storage in the body. The study was carried out by researchers at the universities of Southampton, Exeter and Plymouth.
They used DNA samples from 40 children who took part in the EarlyBird project, which studied 300 children in Plymouth from the age of five until they were 14.
The study assessed the children in Plymouth each year for factors related to type 2 diabetes, such as the amount of exercise they undertook and the amount of fat in their body. A blood sample was collected and stored.
The Southampton team extracted DNA from these blood samples to test for epigenetic switches.
Epigenetic switches take place through a chemical change called DNA methylation, which controls how genes work and is set during early life.
The Southampton team found that a rise in DNA methylation levels of 10pc at five years was associated with up to 12pc more body fat at 14 years. Results were independent of the child's gender, their amount of physical activity and their timing of puberty.
The study, which involved Dr Graham Burdge of the University of Southampton, Professor Terence Wilkin at the University of Exeter and Dr Joanne Hosking at the University of Plymouth, is published in the journal 'Diabetes'.
Dr Burdge said: "It can be difficult to predict when children are very young, which children will put on weight or become obese. It is important to know which children are at risk because help, such as suggestions about their diet, can be offered early.
"The results of our study provide further evidence that being overweight or obese in childhood is not just due to lifestyle, but may also involve important basic processes that control our genes.
"We hope that this knowledge will help us to develop and test new ways to prevent children developing obesity which can be introduced before a child starts to gain excess weight. However, our findings now need to be tested in larger groups of children."