The Genetics of Obesity, Part III

Genetics Loads the Gun, Environment Pulls the Trigger

Thanks to a WHS reader* for reminding me of the above quote by Dr. Francis Collins, director of the US National Institutes of Health**.  This is a concept that helps reconcile the following two seemingly contradictory observations:

1. Roughly 70 percent of obesity risk is genetically inherited, leaving only 30 percent of risk to environmental factors such as diet and lifestyle.
2. Diet and lifestyle have a large impact on obesity risk.  The prevalence of obesity has tripled in the last 30 years, and the prevalence of extreme obesity has increased by almost 10-fold.  This is presumably not enough time for genetic changes to account for it.

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Return to the Source Parkour Camp

For those who are interested in natural movement training, this summer my friend Rafe Kelley will be hosting an interesting three-day event near Bellingham, WA called "Return to the Source".  Rafe is skilled in a variety of movement disciplines and is the co-founder of the Seattle parkour gym Parkour Visions.  Parkour is a very fun sport that hones our natural ability to skillfully navigate physical obstacles, but it's usually done in an urban context.

The camp will take place from August 23-25.  Here's a description from the Parkour Visions site:

"This summer, return to the source of human movement with Parkour Visions as we explore the natural environment in and around Bellingham, WA. Rafe Kelley will introduce you to the benefits of training and playing in nature. You will learn how to adapt your technique and movement to moving effectively through woods, over rocks, and in trees during this unique, 3-day experience."

Watch this video if you want to see what you're in for.

Knowing Rafe, it will be fun and productive.  You can sign up through this page (scroll down).

The Genetics of Obesity, Part II

Rodents Lead the Way

The study of obesity genetics dates back more than half a century.  In 1949, researchers at the Jackson Laboratories identified a remarkably fat mouse, which they determined carried a spontaneous mutation in an unidentified gene.  They named this the "obese" (ob/ob) mouse.  Over the next few decades, researchers identified several other genetically obese mice with spontaneous mutations, including diabetic (db/db) mice, "agouti" (Avy) mice, and "Zucker" (fa/fa) rats.

At the time of discovery, no one knew where the mutations resided in the genome.  All they knew is that the mutations were in single genes, and they resulted in extreme obesity.  Researchers recognized this as a huge opportunity to learn something important about the regulation of body fatness in an unbiased way.  Unbiased because these mutations could be identified with no prior knowledge about their function, therefore the investigators' pre-existing beliefs about the mechanisms of body fat regulation could have no impact on what they learned.  Many different research groups tried to pin down the underlying source of dysfunction: some thought it was elevated insulin and changes in adipose tissue metabolism, others thought it was elevated cortisol, and a variety of other hypotheses.

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Food Reward Friday

This week's lucky "winner"... beer!!

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The Genetics of Obesity, Part I

Choosing the Right Parents: the Best Way to Stay Lean?

In 1990, Dr. Claude Bouchard and colleagues published a simple but fascinating study demonstrating the importance of genetics in body fatness (1).  They took advantage of one of the most useful tools in human genetics: identical twins.  This is what happens when a single fertilized egg generates two embryos in utero and two genetically identical humans are born from the same womb.   By comparing identical twins to other people who are not genetically identical (e.g., non-identical twins), we can quantify the impact of genes vs. environment on individual characteristics (2).

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Food Reward Friday

This week's lucky "winner"... low-carb gluten-free bacon chocolate mocha ice cream cake!!

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Food Reward Friday

This week's lucky "winner"... cronuts!!

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