Exercise Trumps GenesThursday, September 3, 2009
This is perhaps best demonstrated by the fact that it is almost impossible to find genetically identical individuals (or monozygotic twins) with marked differences in body weight.
In contrast, it is much easier to find non-identical twins (who only share some of their genes but the same environment) with great differences in body weight.
Despite this strong influence of genes on body weight, lifestyle can very much make a difference.
This was now demonstrated by Tuija Leskinen and colleagues from the University of Jyväskylä, Finland, who after combing through thousands of twin pairs from the Finnish Twin Cohort, identified seven genetically identical (monozygotic) and nine non-identical (dizygotic) middle-aged (50-74 years) same-sex twin pairs who reported a long-term discordance for physical activity (International Journal of Obesity).
Irrespective of the genetic make up, the physically inactive co-twins had a 50% greater visceral fat area, a 170% higher liver fat score, and 54% more intramuscular fat.
This study clearly demonstrates that even in individuals who share the same genes and/or similar childhood environments, regular physical exercise can prevent the accumulation of high-risk fat over time.
Thus, whatever your genetic background or early childhood environment, it is better to be regularly physically active than sedentary (who would have guessed?).