Thin parents 'pass on skinny genes to their children'

Researchers at University College London have carried out the study and found that children with thinner parents are three times more likely to be thin than children whose parents are overweight.

Lead author Dr Katriina Whitaker said it was the first time that intergenerational transmission of thinness had been investigated.

She said: "We know from other studies that children's weights are correlated with those of their parents, but previous research has tended to focus on obesity rather than the other end of the spectrum."

The study recorded the height and weight of parents and up to two children aged two to 15 years from 7,000 families over a five-year period. This was used to calculate the body mass index (BMI) of the different family members, which is ranked on a scale showing whether people have healthy weight.

A healthy BMI is 18.5 to 24.9 while the "overweight" range is 25 to 29.9, and clinical obesity is 30 and above.

The results showed a "strong association" between children's and parents' body size with the strongest predictor of the child’s thinness being the shape of the parents, the 'Daily Mail' reported.

When both parents were at the lower half of the ideal BMI range, the chance of the child being thin was 16.2 per cent, compared with 7.8 per cent when both parents were in the upper half. These children had a BMI of 18.5 or under, which is regarded as "thin".

The study found the chance of a child being thin with a BMI of less than 18.5 was just 5.3 per cent when both parents were overweight and only 2.5 per cent for children whose parents were obese.

The findings revealed almost six per cent of the children were classified as thin under international criteria, that would probably lead to a BMI less than 18.5 in adulthood.

The results suggest that thinness may be inherited, with children of thinner parents being likely to be genetically predisposed to a lower body weight, say the researchers.

The researchers concluded: "These results are consistent with the idea that many cases of thinness are likely to represent the low end of the healthy distribution of weight and, as such, are likely to have a primarily genetic origin."