The genetic predisposition to obesity due to the ‘fat mass and obesity associated’ (FTO) gene can be substantially reduced by living a physically active lifestyle according to new research by a large international collaboration, led by Ruth Loos from the Medical Research Council Epidemiology Unit, in Cambridge, UK, and published in this week’s PLoS Medicine. The researchers found that the effect of the FTO gene on obesity risk is nearly 30% weaker among physically active than in physically inactive adults. This finding holds an important public health message relevant to health care professionals and the wider public as it challenges the widely-held view that obesity ‘is in my genes’ and not amenable to lifestyle changes. On the contrary, this study shows that even those genetically predisposed can reduce their risk of becoming obese by being physically active.