that will keep cancer from growing, but until there's a breakthrough, cantly's advice, don't eat sugar. if you must, keep it to a minimum. >> in fact, i live my life that way. i rarely eat sugar. when you see a sugary drink or if i were to offer you one, what -- with all that you know, what's going through your mind? >> i probably would turn it down and get a glass of water. >> but for most of us, that's easier said than done. >> turns out sugar is much more addictive than i think we had sort of realized early on. >> eric, a neuroscientist at the oregon research institute is using functional mri scanners to learn how our brains respond to sweetness. >> sugar activates the brain in a special way that's very reminiscent of, you know, drugs like cocaine. >> reporter: that's right. cocaine. >> all right. let's give it a shot. >> reporter: i climbed into the mri scanner to see how my brain would respond. that's a straw that's been rigged to deliver a tiny sip of soda into my mouth. >> stay as still as you can, okay? >> reporter: just as it hit my tongue, the scanner detected increased blood

. >> cantly, a harvard professor and the head of the cancer center said when we eat or drink sugar, it causes sudden spike in the hormone insulin, which is serve as a catalyst to fuel certain types of cancers. >> what we're beginning to learn is that insulin can cause adverse effects in various tissues. a particular concern is cancer. >> why? nearly a third of some commoncanters have insulin receptors on the surface. insulin binds to the receptors and signals the tumor to start consuming glucose. every cell in our body needs glucose to survive, but the trouble is these cancer cells also use it to grow. >> so if you happen to have a tumor that has insulinreceptors on it, then it will get stimulated to take up the glucose in the blood stream. it goes into the tumor, and the tumor uses it to grow. >> so you've seen the tumor turn blue, which is essentially reflective of the glucose going into it. >> that's right. >> these cancers much in the same way that muscle will say, hey, i'd like some of that glucose, the falt says, i would like some of that gleekose, the cancers have learned how to