According to the CDC, more than a third of all Americans are obese, which increases the risk of heart disease, cancer and diabetes. But obesity is no big deal to one member of the animal kingdom: Grizzly bears.

Grizzly bears can weigh upwards of 1,000 pounds. In the lead-up to winter, they crank up their calorie intake and pack on the pounds, becoming obese. But unlike us, they don't become diabetic.

Dr. Heiko Jansen, along with colleagues from the Washington State University Bear Center and the biotechnology company Amgen set out to discover why. Dr. Jansen joined Take Two to explain their findings, published this week in the journal "Cell Metabolism."

"The bears are actually extraordinarily sensitive to the main player in diabetes, which is insulin. If you're an obese human, insulin sensitivity goes way down. We become resistant to insulin, our blood glucose levels rise as a result of that, and that produces a whole nasty cascade of events," Jansen said. "The bears don't do that. The bears maintain their insulin sensitivity despite just packing on massive amounts of weight, a lot of that being fat. Here, we have a natural example of an animal that is obese, yet still sensitive to insulin and doesn't have sky-high blood sugar levels."