Lately, people have been talking about the fact that too much sugar can be toxic, as Dr. Sanjay Gupta pointed out on a recent "60 Minutes."

But just ask anyone why they eat so many sweets and refined carbs, and they'll tell you that they feel downright addicted.

On today's show, the first in a series about how sugar is toxic or addictive, you'll have a chance to hear directly from Dr. Nicole Avena, who has done groundbreaking research that explores how sugar can be addictive.

Dr. Avena is a research