dr. david agus. he kept steve jobs alive years beyond what anybody thought was possible. he wrote the most-anticipated book of the year. in "the end of illness," agus makes the staggering admission that man may not ever understand cancer, let alone cure it. but using the science we already have and vast oceans of data, he thinks we can eventually prevent disease altogether. but it can't happen until american boneheads like this fully understand how they're killing themselves. >> when we look in that one of your most important arteries of the heart, called the l.a.d., the big artery going to the heart, there's one lesion in there where there's calcification. these lesions can cause heart attack in the near-term. we all read in the paper about the 45-year-old who went jogging and died of a heart attack. these are the things we worry about. >> reporter: this is my fondness for shtick coming back to haunt me. why has it calcified? >> most predominant is your genetics. you can blame your parents. you inherited predisposition. >> reporter: how does he know this? dr. agus has a

dr. david agus for a story on the future of medicine, i was still certain of my invincibility.look at that. during the c.t. scan, my heart rate is a beautiful 50 beats a minute. but what this machine found inside my ticker changed my life. >> when we looked in that one of your most important arteries in the heart called the l.a.d., there is one lesion in there. where there's calcification. >> reporter: given my genetics and lifestyle, the doc tells me that a heart attack could come on a ski slope or jogging path within five years. unless i make some changes. but you don't need a $1,300 c.t. scan to snap you into a healthy life. and my experience is universal. >> so, i don't want you on a low-fat diet. i want you on a good-foot diet. olive oil, canola oil, the heart-healthy eggs, cold-water fish, fantastic. >> reporter: workouts are fine. but it's more important to move throughout the day. he says sitting for eight hours a time is as harmful as smoking. >> so, real food. regular schedule. live healthy. that's the key. >> reporter: it took modern technology to teach me old-fashio

dr. david agus suggests that "the end of illness" won't come from miracle cures but from smarter living.ks we can prevent disease altogether using science we already have. >> so the key is know yourself. >> okay. >> the key is to note various aspects of yourself, and so the first is establish your metrics. >> reporter: even doctors in davinci's day understood that health comes from a system in balance. agus says your system is constantly sending you clues when it is out of balance. red flags that are literally at your fingertips. >> if your ring finger is bigger than your index finger, you're almost twice as likely to get osteoarthritis. >> reporter: men, keep an eye on your ankles. >> if all of a sudden there's no hair down there that may mean a circulatory problem. all right luckily my ankle hair is okay so far. but if it starts falling out, i know now to ask my doctor about the possible need for a blood thinner. okay, next check, how comfortable are your shoes? while those heels look amazing, your aching feet are trying to send you a deadly serious warning. >> aching feet means inflam

dr. david agus. "nightline" anchor bill weir got a shock when he visited dr.ment of truth, yeah? is that me? >> that is part of you. >> reporter: i thought this would be just another assignment. >> the unfortunate truth is, you have some heart disease now. >> reporter: the first thought, i flashed to an image of my kid, standing on the same mountain write spread my dad's ashes opinion second thought, i deserve this. whoo! you see, for my first four decades, i carried a secret, arrogant hunch that i was bullet froo proof. sure, i exercise. but i don't have a doctor. i like a salad. my favorites are spare ribs and six pax. and there is the result. in that red. >> one of the most important arteries in the heart, the l.a.d., there's one legion in there where there is kacalcify occasion. we hear or read in the paper about the 45-year-old who went jogging and died of a heart attack. these are the things we worry >> this is my fondness for steak coming back to haunt me? why is it kals fied? >> your genetics. blame your parents. you inherited a predisposition. >> repo

dr. david agus, has written a new book called "the end of illness." longer and healthier. in today's piece, dr. richard besser explains how a simple blood test might lead to the end of illness. >> reporter: what if we could find the key to making every person on the planet live longer and healthier? that's what dr. david agus is looking for. >> we can look at blood markers for disease. >> reporter: he's a researcher professor, and cancer doctor to the stars, treating patients like lance armstrong and steve jobs. his goal is grand. short-circuit our disease before it starts. do you really see a path to the end of illness? >> i do. i think we can really delay most diseases until our ninth or tenth decade. >> reporter: for one thing, he believes his research may change the way we look at and treat cancer. imagine a drop of blood being all your doctor needs to catch an illness, even cancer, in its earliest stage. it's the budding science called proteomics. or the study of proteins. in the name of journalism, i gave blood to have my proteins tested. and he

dr. david agus suggests that the end of illness won't come from miracle cures but smarter living.ease altogether using science we already have. >> so the key is know yourself. >> okay. >> the key is to know various aspects of yourself. and so the first is establish your metrics. >> reporter: even doctors in da vinci's day understood that health comes from a system in balance. and agus says your system is constantly sending you clues when it is out of balance. red flags that are literally at your fingertips. >> if your ring finger is bigger than your index finger, you're almost twice as likely to get osteoarthritis. if you're a woman, finger length correlates to testosterone exposure in utero. >> reporter: so if that ring finger is longer, ladies, regular stretching or yoga will take care of your joints. >> down here -- >> reporter: and men, keep an eye on your ankle. >> if all of the sudden there's no hair down here that may mean a circulatory problem. >> luckily my ankle hair is okay so far. >> reporter: but if it starts falling out i know now to ask my doctor about the possible

dr. david agas. he has treated lance armstrong, ted kennedy, steve jobs. and this way he was able to illustrate the theories in his book, "the end of illness." agusthat americans should be focused on preventing sickness altogether, by using the best diagnostic tools we have. and it was all very fun and interesting, until the c.t. scans were revealed. and he pointed out the sickness in my heart. >> these lesions at significant arteries in the heart can cause heart attacks in the near-term. we read in the paper about the 45-year-old who went jogging and died of a heart attack. these are the things we worry about. >> reporter: that picture and his description of it shook me to the core. i had no idea. and ever since, i'm eating better, moving more. dedicated to my own health like never before. and since sharing the story, i've had dozens of people ask the same question i asked him. should everybody have one of these? >> everybody should discuss this with your doctor. >> reporter: and if you do, you'll learn just how controversial this test really is. especially if you are a seemingly healthy person, like me. the american heart association would not