A simple blood test, which can read DNA, may be able to predict whether a child will become obese, according to a recent study.

Researchers at the Universities of Southampton, Exeter and Plymouth used a blood test to assess the levels of epigenetic switches in the PGC1a gene -- a gene that regulates fat storage in the body, according to a press release.

"It can be difficult to predict when children are very young, which children will put on weight or become obese," Graham Burdge, lead author of the story, said in a statement. "It is important to know which children are at risk because help, such as suggestions about their diet, can be offered early and before they start to gain weight."

For the study, researchers 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.

They found that the test, when carried out on children at five years old, differentiates between children with a high body fat and those with a low body fat when they were older.

Their results showed that a rise in DNA methylation levels of 10 percent at five years was associated with up to 12 percent 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 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," Burdge said.

Researchers said they hope their findings will help to develop and test new ways to prevent children developing obesity.

Their findings were recently published in the journal Diabetes.