Think you are overweight? Your genes might be responsible

Genes plays a major role in self-perceived weight status among youngsters, particularly women, a new study has found.

"This study is the first to show that genes may influence how people feel about their weight," said Robbee Wedow from the University of Colorado Boulder in the US.

"And we found the effect is much stronger for women than men," said Wedow.
The research measured the heritability of subjective weight status, which indicates what proportion of variation in a given trait is due to genes versus the environment.

Heritability estimates range from 0 to 1, with 0 indicating that genetics is not a contributing factor at all, and 1 indicating that genetics is the only contributing factor.

The study showed that perceived weight status was 0.47 heritable, said Wedow, who worked along with Jason Boardman.

"The heritability estimates provided us with the first evidence that weight identity may have genetic underpinnings," Wedow said.

The team used data from the US National Longitudinal Study of Adolescent to Adult Health, or Add Health, that has sampled more than 20,000 adolescents into adulthood, including hundreds of twins who were first quizzed about their health beginning in 1994.

All participants in the study were re-sampled during four subsequent in-home interviews running through 2008. First, the body mass index (BMI), or the height-to-weight ratio, of each person was calculated during each of the four interviews.

Then, the participants were asked how they felt about their own weight. Response options included "very underweight," "slightly underweight," "about the right weight," "slightly overweight" and "very overweight.

Boardman said the new study and others like it are important since researchers have repeatedly shown that health assessments are strong predictors of adult mortality.

Some studies have shown that self-health assessments are at least as accurate as health assessments of the subjects made by their physicians, he said.

The researchers emphasised that even when there is a genetic connection to particular human behaviours or traits, social environments and personal choices will always play a major role in shaping outcomes.

The research was published in the journal Social Science & Medicine.