Effect of ‘fat gene’ moderated by exercise
Thursday, 3 November 2011
People genetically predisposed to becoming obese derive considerable benefit from being physically active, and so instead of simply blaming ‘their genes’ for being overweight and thinking nothing can be done, they should make an effort to modify their lifestyle, researchers said this week.
A UK-led analysis, published in PLoS Medicine, showed that the effect on obesity risk of the ‘fat mass and obesity associated’ (FTO) gene is reduced by more than a quarter in carriers who are physically active, compared with inactive carriers.
Researchers at the MRC Epidemiology Unit in Cambridge analysed data on more than 218,000 adults and found that carrying a copy of the FTO gene confers an increased risk of becoming obese. But they also showed that the increase in risk was only 1.22-fold in physically active carriers, compared with 1.30-fold for carriers who were physically inactive – a 27% reduction.
The study’s authors say their findings emphasise the importance of a healthy lifestyle for people with a genetic predisposition to obesity, in “contrast with the determinist view held by many that genetic influences are unmodifiable”. They add that their results bring more personalised healthcare a step closer, by allowing targeted treatment of those who will derive most benefit from it.
The writer of an accompanying editorial argues that “screening individuals for genes that predispose to obesity makes little clinical sense and may even do harm”. He said: “Genes may co-determine who becomes obese, but our environment determines how many become obese … A focus on individual genetic traits is a mere distraction and reinforces the popular view of obesity as a problem that individuals have to deal with, rather than one that requires societal action.”
In any case, he points out: “Testing for genetic traits that are associated with obesity makes no difference in the advice to overweight persons: increased physical activity and a healthy diet are indicated regardless of the genes.”