dr. amon, let's talk about overeating. anybody would know it's wrong to overeat, it's bad to be fat, so why would you overeat? doesn't the brain tell you that's too much? >> not really. in fact, as your weight goes up, the actual physical size of your brain goes down. so your judgment -- >> larry: you get dumber? >> you get dumber, your reasons goes down in the studies that we have done so being healthy is critical to thinking right. but if you have had a brain injury, overeating goes up. if you have been eating badly for a long time, you become addicted to the bad foods, the fat, sugar and salt when you put them in certain combinations, they actually work on the heroin or morphine centers of the brain. >> larry: they say to exercise, can you exercise your brain. >> yes, you can. the first thing to do would be besides taking good care of yourself physically and proper supplementation would be use it to use various strategies to strengthen certain connections and also remove and release trauma,

dr. daniel amon, author of "breaking the addictions that are stealing your life." and noted clinical psychiatrist, author too of "code to joy." first, cara, what is a neuroscience researcher? >> somebody who studies the rain, really, i mean in all aspects. neuroscience is actually a broad term. it can be neurobiology, it can be neuropsychology. >> larry: do you write or teach or both? >> i have in the past some teaching while i was on my way to my degree. >> larry: let's get to the overall topic, the brain. why does the brain not stop us from doing things we know are wrong. >> it would make sense if you had an evolutionary point of view that the brain was a perfect instrument that only increased our survivability or. and trying to decide why the brain isn't a perfect system in how to operate, what tease correlation between the mind and a brain. the best way i can communicate to it me. music has an existence of its own, it can be shaped and changed, but it's dependent on the violin and the bow to be creative. >> larry: dr. amon, let's talk about overeating. anybody