By Dr. Mercola

Dr. Michael Greger is a nutrition expert, physician, and founder of NutritionFacts.org, is the author of an excellent new book, "How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease."

In it, he examines the 15 top causes of premature death in the U.S., including heart disease, cancer, diabetes, high blood pressure, and more, and reveals how to eat and live for a long healthy life.

The title of the book does not imply that you can achieve immortality, but rather it refers to how to avoid dying prematurely, in pain, after long, chronic, disabling illness.

What motivated him to focus on nutritional medicine was watching his grandmother get well after being diagnosed with end-stage heart disease. After multiple bypasses, she was sent home to die, with only weeks to live.

As fate would have it, she heard about Nathan Pritikin on 60 Minutes, an early lifestyle and alternative medicine pioneer. Pritikin has since passed on but she made it to his clinic, which offered a live-in program, and a few weeks later, she was walking 10 miles a day, and went on to live another 31 years until the age of 96.

How could that be?

"They put them on a plant-based diet, graded exercise programs; started getting them walking in 10-minute intervals, and just gradually ramped that up.

This shows that a healthy diet and exercise cannot just change the structure of the arteries and clean up some of those plaque over the years, but actually change their function," Dr. Greger says.

"You can get almost immediate improvements within days in terms of angina and some of these other problems ...

And then, of course, Dr. Dean Ornish in 1990 published his Lifestyle Heart Trial, a randomized controlled trial that proved ... you can reverse heart disease, the No.1 killer – without drugs, without surgery – with a healthy diet and other lifestyle changes. That's what did it for me."

The Creation of NutritionFacts.org

While initially convinced that this information would revolutionize medicine and abolish heart disease, he quickly came to realize how naïve such a notion was. As the decades wore on, people were still dying from heart disease in ever growing numbers, and diet still didn't make it into the doctors' offices.

"People continue to die and people continue to get useless or worthless therapies for the chronic diseases from the mainstream medical profession," he says.

"When I realized that, I said, 'Wait a second, if you can effectively bury the cure to the No.1 killer, what else is out there in the medical literature that has been buried because there's no corporate budget to drive its promotion?'

I made it my life's mission to unearth all the stuff that has been buried in the dusty stacks of medical libraries and bring it to light. I actually gave up my private practice and started going around the country, speaking at all the medical schools trying to give these lifestyle tools to future physicians.

Then I decided to circumvent the physicians, and go straight to the public. We're talking about low-cost, simple, safe, and side effect-free solutions. You don't have to wait for your doctor to tell you to stop smoking – just stop smoking!

So I started this website, NutritionFacts.org. I just put all my work up online for free. I've been doing that for a couple of years now."

He now has 10 researchers working on the site, and more are still needed to sift through the 24,000 articles published in the nutrition literature in the English language every year.

That amounts to about 70 papers per day — far more than any one human could possibly absorb.

If you were to assume that a physician knew everything there was to know by the time he graduated medical school, and committed to reading three papers from the medical literature each night, by the end of one year, he'd already be 150 years behind on the science.

Many assume that doctors are more or less all-knowing when it comes to medicine, but the fact is that by the time they finish medical school, everything they learned is already obsolete. This is why it's so important to do your own homework, and NutritionFacts.org is a great resource.

My guess is that in the not too distant future we will be able to deploy deep learning strategies like IBM Watson to do this task and provide us with magnificent revelations about the nutritional literature.

For Optimal Health and Longevity, Exercise 90 Minutes Per Day

Dr. Greger is definitely a man who walks his talk — in fact, he did this interview while walking on a treadmill — and the reason for that is because he recognizes the critical importance of staying in motion.

Before talking to Dr. Greger, I was pretty proud of the fact that I walk about 17,000 steps a day (about 9 miles), which is still within the upper 1/10th of 1 percent of people walking with trackers. But Dr. Greger puts even me to shame. He walks 17 miles a day!

“But I go really slow. I’m going about 2 miles an hour now; my heart rate doesn’t even really go up. It’s basically just keeping my arteries happy,” he says. “The current recommendation for moderate aerobic physical activity is 150 minutes a week. That’s like 22 minutes a day.

But if you look at the research, it's very clear — yes, any amount of exercise is better than no exercise, but if you go from 20 minutes a day to 40 minutes a day, [you see] significant improvement.

Go from 40 to 60, significant improvement; 60 to 90 minutes a day, significant improvement, like doubling your mortality benefit ...

That's why in the book I recommend 90 minutes a day because that's what the science shows. You don't necessarily have to do it for optimal health, but people deserve to know what the best available evidence shows."

The science is equally clear when it comes to inactivity. Chronic sitting actively promotes dozens of chronic diseases, including obesity and type 2 diabetes, even if you're very fit and exercise regularly, so simply standing up more is a step in the right direction.

One recent study showed that standing for at least six hours a day may reduce your risk of obesity by 32 to 35 percent depending on your gender. Men can reduce their risk of obesity by as much as 59 percent by standing 12 hours a day.

In fact, standing up as much as possible appears to be a crucial component of a healthy lifestyle that promotes longevity. It's not only that exercise has benefits, but that inactivity has significant dangers. Thirty years ago, research from Cooper's clinic in Dallas showed that exercise was associated with a dramatic reduction in the rate of cancer. This is a well-accepted, non-controversial scientific fact, and it goes beyond its effects on obesity.

Today, I believe I finally understand the mechanisms responsible for these results, and it's because exercise upregulates dysfunctional mitochondria. I now firmly believe mitochondrial health is the core of most cancers. Mitochondrial dysfunction is what causes the genetic problems. It's not the genetic problems that cause the cancer.

And mitochondrial dysfunction is what you prevent with exercise. I'd never recognized that before, but now it seems quite clear that this is how it works. I recently interviewed Rhonda Patrick, PhD, a biomedical scientist, on this topic. That interview will be published shortly, so for more in-depth information about the role of mitochondria in your health, keep an eye out for that interview.

The Link Between Infectious Disease and Domestication of Animals

Dr. Greger's book contains a load of interesting facts I've not previously encountered. For example, the connection between infectious diseases and the domestication of animals. This stems from his work with the Humane Society, which he is the public health director of. His post-graduate medical training also focused on infectious disease and public health. He worked the acquired immune deficiency syndrome (AIDS) wards before the advent of protease inhibitors.

"When I was growing up, there was no such thing as AIDS. I wondered 'Where did this come from?' It was just such a devastating illness. When you look back ... it was a so-called zoonosis — an animal to human disease tied to the bushmeat trade and eating primates in Africa, which spread [the disease] around the world," he explains.

When he investigated further, he realized that about 70 percent of all emerging or reemerging infectious diseases actually originate in the animal kingdom. Going back to animal domestication about 10,000 to 14,000 years ago, that's when the first infectious diseases emerged.

Prior to domesticated ducks and water fowl, influenza didn't exist. The common cold appears to have originated in horses; measles came from rinderpest, a bovine disease; and smallpox likely came from camelpox in camels.

That really raises questions about how the treatment of animals today impact future pandemic risks. He believes selecting pigs and chickens for mass production may be a major mistake, as these are influenza-bearing animals. Modern livestock practices compound the problem by feeding the animals antibiotics, which has led to the emergence of antibiotic-resistant infections.

What Is a Healthy Diet?

The short answer to this question is: real food. It couldn't get much simpler than that really. That means food in its natural state, as it grew on the vine, tree, bush, or in the ground. And when it comes to animal foods, two key factors are: living conditions and diet. Real food is raised in accordance with nature, and the animals are allowed to eat their natural diet, without added drugs and fillers.

"It's almost too easy. People want some kind of trick or magic bullet or something. There has to be some tricks, some tips. But when people actually take those three words — Eat Real Food — to heart, they can revolutionize their health. What I hope is the take-home message from the book is optimism. We have tremendous control over our health destiny, our longevity, and our level of disability."

"The power is in our hands and on our plates," Dr Greger says. "That's the message you don't hear. Because the message you hear is, 'We have a pill for your disease ... We can treat your diabetes. Don't worry. Look, later on, we can do surgery. Eat however you want; live however you want.' That's the message that's coming across enriching the drug companies at the expense of Americans' health."

Whole Food and Your Microbiome

Ideally, you want to get lots of fresh vegetables, which are best eaten as close to their raw state as possible. Moreover, your veggies should be grown in healthy soil. The microbial diversity in healthy soil is very similar to your gut, and if you eat fresh vegetables from healthy soil, a significant number of those microbes will be on the veggies you eat, and will contribute to your own microbial diversity, which is important for optimal health.

It's not only the vegetable fiber and the phytonutrients that feed your microbiome but also these other microbes from the soil in which they were grown. According to Dr. Greger, higher consumption of vegetables may cut your odds of depression by as much as 62 percent, and I suspect this has a lot to do with the fact that they improve the balance of beneficial bacteria in your gut.

As noted by Dr. Greger:

"I was surprised to learn that to make sauerkraut you don't add a microbial starter. You don't have to buy the bacteria, like the yogurt starter. No. You simply take cabbage leaves, and you put them in salt water, so the bad bugs don't grow, and the Lactobacillus, the lactic acid-producing bacteria that are naturally present out in the field and on the leaves, are the ones that will multiply, sour up, and pickle the cabbage.

People think they need to go to the pharmacy to get probiotics. The probiotics are there [in the food]. The same kind of acidophilus, the same kind of lactobacillus, the same kind of probiotics that are sold in the supermarket are present naturally on raw fruits and vegetables...

Raw fruits and vegetables, also offer prebiotics, the fiber, they actually feed the good bacteria you have and can replenish good bacteria if you suffer some gut microbial insult by having antibiotics or something.”

Drink, and Eat, Your Tea

Dr. Greger's book also contains a Daily Dozen checklist of foods he believes everyone should eat more of — foods that can make any meal healthier. For example, you can make any meal healthier by adding dark green leafy vegetables to it. But his book also includes a variety of novel yet simple tips you may never have thought of, such as adding your tea leaves to your smoothie rather than tossing them after making a cup of tea.

One caveat though: be careful with where you source your tea. For example, China just stopped using leaded fuel in 2000, so Chinese tea may still contain elevated levels of lead. Tea originating in Japan tends to have much lower lead levels. Like me, Dr. Greger recommends matcha tea leaves, which is powdered green tea leaves.

"It might not be a good idea for pregnant women and small children," he says. "And if you're doing it a lot, you really want to know the source of your tea. That's the only caveat. Definitely drink and eat your tea."

Death Row Nutrition — Curious Conclusions of Last Meals

Another chapter in Dr. Greger's book that really fascinated me was "Your Last Meal: Death Row Nutrition." This intriguing title came from a study that did a nutritional analysis of the last meals ordered by death row inmates. They essentially wanted to find out what kinds of food people would choose if future health risks were not part of the equation.

"People are like, 'If I'm going to get heart disease 20 to 30 years from now, I don't even want to think about it. The French fries are right in front of me.' It's easy to say, 'Oh, I'll just eat the doughnut and not think forward of the future.' But what if you know you're going to die tomorrow because you're going to be executed tomorrow? There's no concern about the future at all. What would people actually eat?"

The conclusion they came to is that people who know they're going to die tomorrow opt for the standard American diet. There was no major difference between what the inmates ate as their last meal, and the "garbage" the average American eats, who has an entire lifetime ahead of them.

"That suggests that people really are not taking their health into account when they're sitting down to meals," Dr. Greger says. "That was a big wakeup call and really speaks more to how bad the standard American diet is at this point, thanks to the corporate culture that have shoved this down our throats. That was what these inmates are eating. That was pretty scary."

Important Considerations for Vegans

Dr. Greger is vegan — a choice he made both for health and philosophical reasons. As the public health director of the Humane Society, he also doesn't want to be a hypocrite by eating meat. But there are some downsides to avoiding animal foods. He addresses these issues on his website, and in his book. Two nutrients of great concern are B12 and carnitine.

"B12 is a critical issue for anyone eating a plant-based diet even ovo-lacto vegetarian or flexitarian diets," he says.

“You need a regular reliable source of vitamin B12. It’s absolutely critical. I have these horrific videos showing people going blind, people with spinal cord degeneration, people getting paralyzed, and people dying from not having enough vitamin B12. It’s one of the two vitamins not made by plants. One is vitamin D...the other is vitamin B12... I recommend at least 2,500 micrograms once a week.”

One of the problems with B12 is that it's a very large molecule, and unless you have an intrinsic factor to enhance the absorption in your intestine, it's not going to be absorbed well. So oral B12 typically doesn't work well.

Sublingual drops and intramuscular injection have better absorption rates. The 2,000 micrograms per week is the oral supplement dose Dr. Greger recommends, which is about 2,000 times the amount you actually need every day. Only 1 percent gets through the intestine, which is why you need such a high dose. Fortunately, you cannot overdose on B12, so you're better off erring on the high side.

And then the carnitine, an animal protein essential for the transport of fatty acids into the mitochondria. The enzyme carnitine palmitoyltransferase is upregulated by about 20 percent in people who eat plant-based diets, but the reason is still unknown. It could be due to the fiber content, or perhaps the microbiome effect.

"The reason carnitine is in muscles, is in meat, is because animals make it. We are animals and we make it, too ... There are enzyme systems that actually create carnitine in our body ... About one in 20,000 to 30,000 births has a deficiency in creating carnitine, but would never even know it if they ate meat.

If they're eating meat their whole lives, they're getting carnitine this way instead of their own body making it. Should they go vegetarian, they're going to end up in the hospital ... So what do they do? They take carnitine supplements and they're fine."

Can You Be an Unhealthy Vegan?

Most people who start eating a plant-based diet will feel very energized and will note a variety of health improvements. However, some people fail to thrive on a plant-based diet, and many times either B12 deficiency, carnitine deficiency, or both, are to blame. Dr. Greger notes that vitamin D deficiency is also rampant among vegans who fail to thrive.

Many of the problems associated with veganism can be avoided by eating a wide variety of real food. It may not have occurred to you, but you can actually be a very unhealthy vegan these days. The devil is in the details, as they say, and many vegans are essentially just eating a vegan junk food diet.

Dr. Greger expounds on this issue, noting:

"It used to be that if you are a vegetarian, you had to by default eat healthy. What was there to eat? Now we have vegan doughnuts. We have vegan lard, vegan ice cream, vegan everything. It's like the gluten-free thing. Celiac patients used to be really healthy. What could you eat? You couldn't eat any junk food, right? You just had to eat real food.

Now we got gluten-free Oreos or whatever you want to stuff in your face. Now you can eat just as unhealthy gluten-free as a non-gluten-free. The same thing with vegan. It has become so popular that you can get every disgusting processed food in vegan form. I see that a lot among college vegans. They're not doing well because they're not eating real food. That's important.

If you look into some of the longest living countries, like Okinawa for example; they were eating animal products, but they were eating 95 percent whole plant foods. That's a much healthier diet than your strictest of the strict, 100 percent vegan here in the U.S. living on vegan Doritos."

More Information

To learn more about how to eat yourself well and avoid dying riddled with disease, I highly recommend picking up a copy of Dr. Greger's fascinating and highly useful book, "How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease." Diabetes, high blood pressure, heart disease, and cancer — these are health problems you CAN avoid, if you're willing. You can eat like you want to live into your 90s, or you can eat like you're on Death Row. The choice is yours.

The book comes with a free app for iPhone and Android, scheduled to be ready in January, which helps you track your daily food intake. It can serve as a reminder to get the recommended daily servings of Dr. Greger's Daily Dozen list. For example, he recommends eating a quarter teaspoon of turmeric every day, or half an inch of fresh turmeric root.

Fresh turmeric is preferable, and it's fairly inexpensive at $20 per pound. If you buy in bulk, you can freeze it for up to a year. Flaxseed is another item on the Daily Dozen list. I've known for three decades the importance of flaxseeds but for some reason I simply forgot to include them in my diet until I read "How Not to Die."

The lignans in flax seeds are powerful soluble fibers and they digest short-chained fatty acids, which is tremendous metabolic fuel for gut bacteria and the cells in your colon. Considering how inexpensive flaxseeds are, it's crazy not to use them.

"Look, my diet changes very much as everybody else's. I'll come home from the library and my family's like, 'What can't we eat now,' or 'Why does everything have parsley in it all of a sudden?' I'm learning as much as everybody else. In fact, I'd probably be doing this work even if nobody looked at it," he says.