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.
The authors performed a comprehensive literature search and invited all researchers who had reported on the FTO gene in the past to participate in their study. They used an extensive and innovative methodology to analyze data from over 218,000 adults, to show that, in general, carrying a copy of the FTO gene increases the risk of becoming obese. However, the effect of the FTO gene on obesity risk was 27% less pronounced in individuals who were physically active (1.22 fold) compared with those who were physically inactive (1.30 fold).
The authors say: "Our findings are highly relevant to public health. They emphasize that physical activity is an effective way of controlling body weight, particularly in individuals with a genetic predisposition towards obesity. Thus, they contrast with the determinist view held by many that genetic influences are unmodifiable." The researchers believe that these findings will bring them a step closer to more personalised healthcare by identifying people who will benefit most from a targeted treatment.
In an accompanying Perspective, J. Lennert Veerman from the School of Population Health at the University of Queensland in Australia says: "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." Dr Veerman continues: "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."
Article by Ruth Loos and colleagues
Funding: There was no specific funding for this project/meta-analysis. Funding sources for the individual authors and for the studies included in the meta-analysis are listed in Text S2. The publication is the work of the authors, and the views in this paper are not necessarily those of any funding body. No funding body has dictated how analyses were undertaken or results interpreted, and Ruth Loos acts as guarantor for the contents.
Competing Interests: JJN has, since January 2011, been employed at Steno Diabetes Centre, a legally independent clinical and research body, which is wholly owned by Novo Nordisk. In relation to his contribution to this manuscript (through the RISC study), all of this work pre-dates his appointment to his current position. All other authors have declared that no competing interests exist.
Citation: Kilpeläinen TO, Qi L, Brage S, Sharp SJ, Sonestedt E, et al. (2011) Physical Activity Attenuates the Influence of FTO Variants on Obesity Risk: A Meta-Analysis of 218,166 Adults and 19,268 Children. PLoS Med 8(11): e1001116. doi:10.1371/journal.pmed.1001116
MRC Epidemiology Unit
Genetics of Obesity programme
Addenbrooke's Hospital - Box 285
Cambridge, CB2 0QQ
+44 1223 769139
+44 7824 605011
Perspective by J. Lennert Veerman
Funding: JLV is supported by an NHMRC Capacity Building Grant (no. 456002). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The author has declared that no competing interests exist.
Citation: Veerman JL (2011) On the Futility of Screening for Genes That Make You Fat. PLoS Med 8(11): e1001114. doi:10.1371/journal.pmed.1001114
J. Lennert Veerman
School of Population Health
University of Queensland
+61 7 336 55367