Genetics loads the gun; lifestyle pulls the trigger

Philip J. Goscienski, M.D.

September 2006

The genes that your mom and dad passed on to you determined your eye color, your height and most of your personality traits and there's not much that you can do about those. Of the thousands of genes that each of carries there are also some that put us at risk of disease but not all these diseases are inescapable. It's ironic that the diseases that kill most of us, though influenced by our genes, are mostly avoidable. And the leading ones such as heart disease, cancer and stroke are strongly associated with obesity.

Like a loaded gun, these genes cause no damage unless someone pulls the lifestyle trigger.

There are dozens of genes that are related to obesity and nearly everyone on the planet has at least a few of them. Not a single one of these genes will cause a person to become obese unless that individual also takes in more calories than he or she uses up. On the other hand, some genes make our fat-accumulating mechanism extremely efficient while at the same time making it hard to burn off fat. In the thousands of years before food supplies became stable it was an advantage that helped humans to survive periods of food scarcity. That survival trait has become a deadly disadvantage in a world where fewer and fewer humans worry about tomorrow's meal.

There are many genes that determine our tendency to develop type 2 diabetes. Whether we have those genes or not we can avoid it completely if we maintain normal weight, perform adequate physical activity and avoid those foods that cause a brisk rise in blood sugar levels.

The members of one particular Native American tribe, the Pimas of the Southwest, have become the poster children of diabesity, the combination of obesity and diabetes. They are the most obese population group that has ever been studied and their burden of type 2 diabetes is appalling. Of Pima women over the age of 55, 80 percent have diabetes and almost all are either obese or overweight.

Their genetic gun is loaded with type 2 diabetes but it would be harmless if they imitated the lifestyle of their genetically identical cousins in central Mexico. The Mexican Pimas separated from the original group and migrated south about 800 years ago. Obesity and type 2 diabetes are rare among them. High blood pressure, heart disease and kidney failure are almost absent in the south but shorten the lives of many Pimas in the north. Considering that the Mexican Pimas weigh 57 pounds less, on average, than their North American relatives, we should not be surprised.

The lifestyle triggers are easy to identify in Arizona and New Mexico. A diet that is high in processed foods, refined wheat and sugar and a lifestyle that averages only 7 hours a week in physical activity are killing the northern Pimas.

Genetics loads the gun; lifestyle pulls the trigger. Spread the word.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.