Wednesday, February 13, 2008

Are You Fated to be Fat?


A study was published last week to a great deal of media fanfare.

The study Evidence for a strong genetic influence on childhood adiposity despite the force of the obesogenic environment, published in the American Journal of Clinical Nutrition, details twin analyses whereby 5,092 twin pairs (some identical, some fraternal) were monitored for weight change. Comparing the weight change over time of identical twins versus those of fraternal twins was used to help determine the degree of nature vs. nurture on weight gain.

The researchers concluded that the vast majority of weight was heritable, or genetic in nature and in their discussion they make a point of noting,

"What is important is this finding means that “blaming” parents is wrong"
I'll come back to that in a moment.

First let's look at North America where roughly 70% of the population is now overweight or obese.

Clearly our genes haven't changed in the past hundred years or so, something the authors of the paper readily agree to.

So if our genes haven't changed yet the study is blaming obesity on our genes, why is it that obesity has become such a concern now?

George Bray perhaps said it best,
"Genes load the gun and the environment pulls the trigger"
So does that mean parents aren't to blame? Their kids have these fat genes and there's nothing we can do about it? They and worse yet their kids are fated to be fat?

No, though blame is a very strong word.

While certainly it's true that the interactions of genes with our obesogenic environment are what's responsible for the rapidly rising weight of the world, given the percentage of folks gaining weight, clearly those genes are pretty darn common. Therefore if you're a parent with however many kids and one or more of them are overweight or obese, at the end of the day does that mean there's nothing you can do about it?

Of course not.

While you can't change the outside environment, certainly your home's foodscape is within your explicit control. You're responsible for the foods in your cupboards, you're responsible for how much viewing time or internet time your children are allowed, and most importantly, you're responsible for both the example you set in terms of eating behaviours and also you're responsible for learning about nutrition, caloric intake and expenditure and healthy living as a whole and you alone are responsible for trying to pass that knowledge on to your kids.

Again, blame is a sharp word and if I'm going to wield it, I like to blame our government and public health systems for not providing parents with the necessary tools to properly understand the impact of the environment on weight nor the skills to maintain a healthy weight within our environment.

Long post short - 100 years ago obesity wasn't a problem; our lifestyles were different, which is why a time machine would serve as a fabulous weight loss aid. Certainly the environment is responsible for changing our lifestyles, however we can certainly still live responsibly within that environment, it just takes education, planning and organization.

The only thing your children are absolutely, for better or for worse predestined to be is related to you. Everything else is modifiable.

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