FTO and obesity due to melanocortin 4 receptor deficiency: This is in line with a 2011 meta-analysis on data of 218,166 adults and 19,268 children that showed that the increased risk of obesity due to genetic variation in FTO can be attenuated by physical activity, but did not find an association between FTO variation and a decreased level of physical activity (Kilpelainen et al., 2011).