Friday, September 18, 2009

Genetics & obesity - we can't blame our parents anymore!

There was a recent article that discussed the genetic link to obesity. Research states you have a 2.5x greater risk of being obese if you have 2 copies of the best known gene for overweight and obesity. Hmm, so if Mom & Dad both give me copies of this gene, I'm doomed to be fat? Or worse yet, "obese"? NO!

A study published in the American Journal of Clinical Nutrition(1) found that obesity can be affected by dietary intake and leisure-time activity. Let me summarize:

  • The study followed over 4800 people from a diet & cancer study for which dietary data and genetic information was available.

  • Results indicated that those subjects who consumed a higher fat and lower carbohydrate diet had a higher body mass index (BMI) compared to those who consumed a lower fat diet.

  • Those with an increased BMI also reported less physical activity.

  • The authors concluded that high-fat diets & low activity may accentuate the susceptibility to obesity by this specific gene variant.

Well...sounds like nothing new. We all knew that high fat intake (not to mention, high sugar) combined with little exercise leads to obesity. However, the key to this study is that you're not destined to be obese simply because you have 2 copies of this gene! Genetics can be changed with lifestyle modification! That is GREAT news (in my opinion, anyway!)

Keep in mind some study limitations:

  • it's a cross-sectional study, which just looks at a subset of people at a given time. This limits the ability to investigate actual cause (seems like a big limitation)!

  • This is also only a "snap-shot" of 1 week of a subjects self-reported food intake, not a view of his whole life

  • Some of the associations made between diet, exercise & obesity may be lessened due to a dietary recall method relying on a subjects ability to accurately report intake and activity.

Bottom line: despite all the limitations of this study, it still provides us with information that you're not destined to a life of obesity predicted by your genes! Make healthy choices most of the time, be active daily and you can positively change your genetic predisposition!


1. Sonestedt E. et al. Fat and carbohydrate intake modify the association between genetic variation in the FTO genotype and obesity.

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