Changes in our lifestyle, including increased energy intake and lack of physical activty, have been a driving force behind the dramatic increase in obesity prevalence over the past few decades (Li, Zhao, Luan, Ekelund, Luben, Khaw, Wareham & Loos, 2010). Recent genome wide association studies have identified 12 loci (location of a gene on a chromosome) robustly associated with increased body mass index. This being so, loci can have an cumulative effect on body mass index and on the risk of obesity and that, collectively, these 12 loci can be used to estimate an individuals genetic predisposition to obesity.
A new study of 20,430 individuals examined whether the genetic predisposition to increased BMI and obesity risk is modified by self reported daily physical activity (Li, Zhao, Luan, Ekelund, Luben, Khaw, Wareham & Loos, 2010) . To examine a genetic determinant, researchers from the University of Cambridge evaluated the genetic makeup of each participant including the genes associated with body mass index, level of physical activity and the changes in body mass index over the course of the study (participants were followed for 4 years).
This study found that the number of body mass index-increasing genes related to obesity in the population as a whole, but the association was far greater in inactive individuals than in those with the highest levels of physical activity. According to the results of this study, physical activity accounts for a 40 percent reduction in the likelihood that a gene/s will result in obesity. This being so, it may be possible to modify genetic tendencies with lifestyle choices.
Li, S., Zhao, J.H., Luan, J., Ekelund, U., Luben, R.N., Khaw, K.T., Wareham, N.J. & Loos, R.J.F. 2010. Physical activity attenuates the genetic predisposition to obesity in 20,000 men and women from EPIC-Norfolk Prospective Population Study. PLoS Med, 31:7.