This is Science Today. Millions of people have type
2 diabetes. Their bodies make insulin but don't
use it, causing perennially high blood sugar, which
causes many other health problems. Millions more
have insulin resistance, a precursor to type 2 diabetes.
Dr. Ira Goldfine of the University of California,
San Francisco says that once, insulin resistance
had survival value.
Goldfine: We think that the insulin resistance gene, many thousands of years ago, was probably beneficial to individuals. In other words, when people were more primitive hunter-gatherers and they didn't eat regularly, those individuals who had genes that kept the blood glucose elevated, the blood sugar elevated, had survival benefit.
Narrator: But now, when we eat all too regularly and don't get enough exercise, that gene catches up with us, because insulin resistance can be triggered by a sedentary lifestyle.
Goldfine: We're not designed to sit around and watch TV and eat potato chips, I think we're designed to be out there doing something, right? And our civilization has only been around for a few thousand years, but our genetics have been around for hundreds of thousands of years, so it makes good sense to try and keep fit.
Narrator: For Science Today, I'm Steve Tokar.