 What if just one lifestyle change could help you avoid getting cancer, or diabetes, or heart disease, or high blood pressure? This one change could cut your risk of chronic disease and add years to your life. Well, the simple solution to so many of these problems is to eat a healthy diet. In other words, one centered around whole plant foods. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. What if you only ate foods that took into account your specific metabolism, your family history, how much you exercised? Would that be helpful? Today we start with the question, how useful is personalized nutrition? Personalized nutrition is rooted in the concept that one size does not fit all, and who doesn't want to think they're special? The concept of personalized nutrition is inherently appealing to the human ego. Simple messages recognizing individuality therefore resonate deeply with consumers, explaining the popularity of such messages in sales and marketing. Even to the point of manufacturing personalized food for people's uniqueness, suggesting 3D food printing is a good candidate for food customization. Now, there certainly are some legitimate differences between people. Some have a peanut, a gene keel over if they eat a peanut, and others have celiac disease and have to avoid gluten, or genetically are lactose intolerant. There's an enzyme mutation common in some parts of Asia that protect against alcoholism, because people with it can't metabolize alcohol as efficiently, so toxic metabolites build up. I did a fascinating video about fast versus slow caffeine metabolizers, and the difference in health benefits. That actually extends to athletic performance. Caffeine is ergogenic, performance enhancing, but only in fast metabolizers, shaving more than a minute off 10 kilometers of cycling, whereas slower metabolizers got no benefit, or caffeine actually slows them down, adding two minutes to their cycling time, depending on which kind of genes they have that codes the enzymes that breaks it down. But for most people, in most situations, we are more similar than different. While there's undoubtedly a specific minority of individuals who clearly require a more personalized approach to nutrition, there is presently insufficient rationale for truly personalized nutrition for the majority of people. Yet there's an astonishing number of direct-to-consumer genetic testing companies that have proliferated offering personalized nutrition advice. For example, supplement-hawking companies claiming to help consumers optimize micronutrient status on the basis of a handful of genetic variants, but the majority of these variants explain just a few percent of the difference in levels between individuals. Personalized nutrition is part of a broader push towards personalized medicine, also known as precision medicine, given the massive cultural allure of personal control over prevention, diagnosis, and treatment of disease, stimulating demand and prompting intense commercialization. But unlike monogenetic diseases, which are rare genetic diseases caused by a single malfunctioning gene, like hemophilia or sickle cell anemia, most diseases are caused by a complex interaction between multiple genes with environmental factors, which pose a major challenge for the realization of personalized medicine. It takes something like adult stature, for example. We've found at least 40 locations on our chromosomes that have been associated with human height, which is strongly inherited. The genes from your parents account for about 80% of the difference in height between people. Yet all those dozens of genes we've found explain only about 5% of height variation between people. Researchers find those genetic links by using what are called genome-wide association studies, where you scan through all the chromosomes and look for statistical associations between diseases and any particular stretches of DNA. Okay, that's interesting, but companies marketing genetic susceptibility tests are doing is reinterpreting these data as if they were predictive of individual risks. But all you're really getting are modest genetic associations with a slight increase in the risk of disease and with little predictive value when compared to more significant contributions of things we already know, like lifestyle behaviors. Currently, the practice of utilizing the DNA of an individual to predict disease has been judged to provide little or no useful information. For example, let's say your genetic analysis says you're at slightly greater risk for some grave condition compared to others in your ancestral group. This person was given advice to exercise, keep their weight down, not drink too much alcohol, and eat fruits, vegetables, and whole grains. Okay, I mean, solid advice, but this is how we should live regardless of our genetic risk. And we all know, or shouldn't know, these simple bedrock strategies to reduce the risk of common chronic diseases in general. The problem, of course, is that very few individuals live that way. Actually, to be more precise, almost nobody lives that way. That's not just hyperbole. Nationwide surveys show that nearly the entire U.S. population consumes a diet that is not on par with even the wimpy dietary guidelines recommendations. In other words, almost no one in the United States is eating a healthy diet. Studies like that remind us that from the perspective of public health, worrying about personalizing or preventive strategies based on genetic risk information borders on the absurd. In our next story, we ask ourselves, if doctors can eliminate some of our leading killers by treating the underlying causes of chronic disease, why don't more doctors do it? Though I was trained as a general practitioner, my chosen specialty is lifestyle medicine. Yes, most of the reasons people go to see their doctors is for diseases that could have been prevented, but lifestyle medicine is not just about preventing chronic diseases, but also about treating them. And not just treating the disease, it's treating the causes of disease. If people just did four simple things, not smoking, exercising half-hour a day, eating a diet that emphasizes whole plant foods and not becoming obese, that may prevent most cases of diabetes and heart attacks, half of strokes, and a third of cancers. Even modest changes may be more effective in reducing cardiovascular disease, high blood pressure, heart failure, stroke, cancer, diabetes, and all cause mortality than almost any other medical intervention. The key differences between conventional medicine and lifestyle medicine is instead of just treating risk factors, we treat the underlying causes of disease, as described in this landmark editorial. See, typically doctors treat risk factors for disease, such as giving a lifetime's worth of medications to lower high blood pressure, elevated blood sugar, high cholesterol, but think about it, high blood pressure is just a symptom of disease dysfunctional arteries. Yes, you can artificially lower blood pressure with drugs, but that's not treating the underlying cause, which often comes down to things like diet and exercise, the penicillin of lifestyle medicine. Disregarding the underlying cause and treating only risk factors is somewhat like mopping up the floor around an overflowing sink, instead of just turning off the faucet, which is why medications usually have to be taken for a lifetime. If a floor is flooded as a result of a dripping tap, it is of little use to mop up around the floor unless the tap is turned off. The water from the tap represents the cost of disease, the flooded floor, the diseases filling up our hospital beds. Yet medical students learn far more about methods of floor mopping than about turning off taps, and doctors who are specialists in mops and brushes can earn infinitely more money than those dedicated to shutting off taps. And the drug companies are more than happy to sell rolls of paper towel so patients can buy a new roll every day for the rest of their lives. Power-phrasing Ogden and Nash, modern medicine is making great progress, but just headed in the wrong direction. Preventive medicine is, frankly, bad for business. When the underlying lifestyle causes are addressed, patients often are able to stop taking medication or avoid surgery. We spend billions cracking people's chests open, but only rarely does it actually prolong anyone's life. In contrast, how about wiping out at least 90% of heart disease? Think about it. Heart disease accounts for more premature deaths than any other illness and is almost completely preventable, simply by changing diet and lifestyle. And those same changes can prevent or reverse many other chronic diseases as well. The same dietary changes. So, why don't more doctors do it? Well, one reason is doctors don't get paid to do it, for no one profits from lifestyle medicine, so it's not part of medical education or practice. Presently, physicians lack training and financial incentives, so they continue to do what they know how to do, prescribe medication, and perform surgery. After Dean Ornish proved you could reverse our number one cause of death, heart disease, open up arteries without drugs, without surgery, just with a plant-based diet and other healthy lifestyle changes, he thought that his studies would have a meaningful effect on the practice of mainstream cardiology. After all, a cure for our number one killer? But he admits he was mistaken. Physician reimbursement, he realized, is a much more powerful, determinative medical practice than research. Reimbursement more than research. Salary over science, wealth versus health. Not a very flattering portrayal of the healing profession, but hey, if doctors won't do it without getting paid, let's get them paid. So, Dr. Ornish went to Washington, arguing that, look, if we train and pay for doctors to learn how to help patients address the real cause of disease with lifestyle medicine, not just treat disease risk factors, we could save trillions. And that's just talking hard to these diabetes, prostate and breast cancer. The Take Back Your Health Act was introduced in the U.S. Senate to induce doctors to learn and practice lifestyle medicine, not only because it works better, but here's the critical factor, physicians will be paid to do it. The bill died, just like the millions of Americans will continue to do with reversible chronic diseases. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org slash testimonials. We may share it on our social media to help inspire others. To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts Podcast landing page. There you'll find all the detailed information you need, plus links to all the sources we cite to each of these topics. My latest two books are How to Survive a Pandemic, Available on e-book, audio book, or actual book, and The How Not to Diet Cookbook with more than 100 recipes for delicious and nutritious meals. All proceeds I receive from the sales of my books go to charity. NutritionFacts.org is a non-profit, science-based public service where you can sign up for free daily updates on the latest in nutrition research via bite-sized videos and articles. Everything on the website is free. There's no ads, no corporate sponsorship. It's strictly non-commercial. I'm not selling anything. I just put it up as a public service as a labor of love as a tribute to my grandmother, whose own life was saved with evidence-based nutrition.