Genetics determines who can get fat not who will.
Some people are more predisposed to fat gain than others. However you have more control than you think, or maybe than you want to admit.
Studies have shown that multiple areas on a person’s DNA (genetic loci) identified by genome-wide association studies (GWAS) increase the susceptibility to obesity in a cumulative manner. That means the more obesity-related factors on your DNA, the more likely you are to accumulate body fat. However, it wasn’t known whether, and to what extent, this genetic susceptibility may be influenced by a physically active lifestyle.
A recent study in Europe examined over 20000 people over a 3.6-year period showed that living a physically active lifestyle is associated with a 40% reduction in the genetic predisposition to obesity.
In this study, the researchers examined the DNA areas that increase obesity-susceptibility in a sample of 20,430 individuals (aged 39-79 y) from the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort with an average follow-up period of 3.6 y.
A genetic predisposition score was calculated for each individual by adding the body mass index (BMI)-increasing areas. Physical activity was assessed using a self-administered questionnaire. Statistical analysis was used to examine the effects of the genetic predisposition score and its interaction with physical activity on BMI/obesity risk and BMI change over time.
Each additional BMI-increasing area increased the risk of obesity 1.116-fold in the whole population, but significantly more in inactive individuals than in active individuals.
What does this mean?
Some people inherit a predisposition to accumulating body fat than others. Others use genetics as a reason for their excess fat. What this study shows is that even if you are predisposed to getting fatter, if you have an active lifestyle, and exercise regularly and consistently, your chance of getting fat is significantly less.
Add to this the risk-reducing effects of exercise, regardless of body fat, and it makes sense to make exercise a part of your day; every day.
Reference: Li S, Zhao JH, Luan J, Ekelund U, Luben RN, et al. (2010) Physical Activity Attenuates the Genetic Predisposition to Obesity in 20,000 Men and Women from EPIC-Norfolk Prospective Population Study. PLoS Med 7(8): e1000332. doi:10.1371/journal.pmed.1000332
