Parents can learn whether their newborn is at risk of becoming fat using a simple online calculator, according to scientists who say obesity can be tackled at birth.
Using a formula based on factors like the child's birth weight, their parents' body size and whether or not their mother smoked during pregnancy, the calculator can predict whether or not the baby is at risk of obesity during childhood.
Other factors include the mother's professional status, with children of less qualified parents more likely to become obese, and the size of the household, with children from smaller families at greater risk.
Researchers from Imperial College London, who programmed the online calculator, said they hoped it could help parents avoid allowing their children to gain too much weight.
Preventing young children from becoming obese is important because it is very difficult for them to lose weight once they have put it on, experts said.
Prof Philippe Frougel, one of the study's authors, said: "This test takes very little time, it doesn't require any lab tests and it doesn't cost anything.
"Unfortunately, public prevention campaigns have been rather ineffective at preventing obesity in school-age children. Teaching parents about the dangers of overfeeding and bad nutritional habits at a young age would be much more effective."
The fifth of children who can be predicted as having the highest obesity risk at birth go on to account for 80 per cent of all childhood obesity cases.
Writing in the Public Library of Science journal, the researchers explained they had based their formula on a study following 4,000 Finnish children, which began in 1986.
Having failed to develop a test based on genetic variations, they found that a variety of information available at birth could reliably predict whether or not children would become obese.
Some factors, such as the child's birth weight and their parents' body mass index, point to a genetic cause but others account for environmental factors, such as the mother's professional status, which broadly indicates their level of education.
Prof Marjo-Riitta Järvelin, co-author of the study, explained: "In our study, we have seen that if socioeconomic status (SES) is defined by education, then lower SES seems to be associated with poorer metabolic states, for example your blood pressure and lipid levels, and also obesity."
Another environmental factor, family size, was also a good indicator of whether a child might become obese because single-parent families have on average one fewer family member, she added.
"You would expect that a larger number of family members would be associated with a higher risk of obesity, but in this case it is actually the opposite," she said.
"If the mother is single then the number of family members is lower ... single mothers are in many ways in a disadvantaged position because they might not have as much money for food, or as much time for their children."
The calculator is available at the following link:https://files-good.ibl.fr/childhood-obesity
Nick Collins - telegraph.co.uk