Exclusive Interview with Dr. Michael Greger

In an exclusive interview with Dr. Michael Greger, one of the leading experts in the field of plant-based nutrition and health, we will delve deeper into the world of healthy eating.

Dr. Greger is known for his evidence-based research and commitment to spreading knowledge and information about the benefits of a plant-based diet. In this interview, We will focus on his research findings and ask him about current nutrition trends to understand how we can improve our health through our diet. Read on to learn more about how a plant-based diet can change our lives.

How important is physical fitness for overall health, and how can one stay physically active even with limited time and resources?

In addition to helping us enjoy a healthier body weight, exercise may also boost our immune system. Studies have found that if we let kids run around for just six minutes, the levels of immune cells circulating in their blood may increase by nearly 50 percent. At the other end of the life cycle, regular exercise may also help prevent age-related immune decline. One study found that while elderly, sedentary women have a 50 percent chance of getting an upper-respiratory illness during the fall season, those randomized to begin a half-hour-a-day walking program dropped their risk down to 20 percent.

Physical activity is also considered a promising preventive measure against breast cancer—not only because it helps with weight control but because exercise tends to lower circulating estrogen levels. Five hours a week of vigorous aerobic exercise may lower estrogen and progesterone exposure by about 20 percent, and moderately intense activity may offer as much benefit as vigorous exercise; walking an hour a day or more appears to be associated with significantly lower breast cancer risk.

Can exercise halt cognitive decline? Researchers took a group of people with mild cognitive impairment (for example, those starting to forget things or regularly repeating themselves) and had them engage in aerobic exercise for 45 to 60 minutes a day, 4 days a week, for 6 months. The control group simply stretched for the same time periods. Researchers found that in the control group, cognitive function appeared to continue to decline. But the exercising group not only didn’t get worse, they seemed to get better, answering more test questions correctly after six months, indicating their memory had improved. Indeed, aerobic exercise may actually reverse age-related shrinkage in the memory centers of the brain and help improve cerebral blood flow, improve memory performance, and help preserve brain tissue.

Exercise may also help prevent and treat high blood pressure, and improve our mood and quality of sleep. If the U.S. population collectively exercised enough to shave just 1 percent off the national body mass index (BMI), 2 million cases of diabetes, 1.5 million cases of heart disease, and up to 127,000 cases of cancer may be prevented.

In my Daily Dozen, I recommend 90 minutes of moderate-intensity activity, such as brisk (four miles per hour) walking or 40 minutes of vigorous activity (such as jogging or active sports) each day.

How can a healthy diet help prevent chronic diseases like cardiovascular disease and diabetes?

Whereas infectious diseases were the primary causes of death during the Age of Pestilence and Famine, our current era of human disease, the Age of Degenerative and Man-Made Diseases, counts lifestyle diseases—heart disease, chronic lung disease, and cancer—as the top killers.

This pandemic of chronic disease has been ascribed in part to the near-universal shift toward a diet dominated by animal-sourced and processed foods—in other words, more meat, dairy, eggs, oils, soda, salt, sugar, and refined grains. China is one of the best-studied examples. There, a transition away from the country’s traditional, plant-based diet was accompanied by a sharp rise in diet-related chronic diseases, such as obesity, diabetes, cardiovascular diseases, and cancer.

The same kind of diet that may help prevent common cancers just so happens to be the same kind of diet that may also help prevent heart disease, type 2 diabetes, and many other leading causes of death. Unlike drugs—which tend to only target specific conditions, can have dangerous side effects, and may only treat the symptoms of disease—a healthy diet can benefit all organ systems at once, has good side effects, and may treat the underlying cause of illness.

That one unifying diet found to best prevent and treat many of these chronic diseases is a whole-food, plant-based diet, defined as an eating pattern that encourages the consumption of unrefined plant foods and discourages meats, dairy products, eggs, and processed foods.

How can families improve their nutrition and encourage their children towards a healthier lifestyle?

In 1990, most years of healthy life were lost reportedly to undernutrition, such as diarrheal diseases in malnourished children, but now the greatest disease burden may be attributed to high blood pressure, a disease of overnutrition. The pandemic of chronic disease has been ascribed in part to the near-universal shift toward a diet dominated by processed foods and animal-sourced foods—more meat, oils, dairy, soda, eggs, sugar, salt, and refined grains.

How can scientists parse out the effects of specific foods? Researchers studied lapsed vegetarians. People who once ate vegetarian diets but then started to eat meat at least once a week experienced a 146 percent increase in odds of heart disease, a 152 percent increase in stroke, a 166 percent increase in diabetes, and a 231 percent increase in odds for weight gain. During the 12 years after the transition away from eating vegetarian, meat-eating was associated with a 3.6 year decrease in life expectancy.

Only one way of eating has ever been proven to reverse heart disease in the majority of patients: a diet centered around whole plant foods. If that’s all a whole-food, plant-based diet could do—reverse our number-one killer—shouldn’t that be the default diet until proven otherwise? The fact it may also be effective in preventing, treating, and arresting other leading killers seems to make the case for plant-based eating simply overwhelming.

And it’s never too early to start eating healthfully. In 1953, a study published in the Journal of the American Medical Association radically changed our understanding of the development of heart disease. Researchers conducted autopsies on 300 American casualties of the Korean War, with an average age of around 22. Shockingly, 77 percent of soldiers already had visible evidence of coronary atherosclerosis. Some even had arteries that were blocked off 90 percent or more.

Later studies of accidental death victims aged 3 to 26 found that fatty streaks—the first stage of atherosclerosis—were in nearly all American children by age 10. By the time we reach our 20s and 30s, these fatty streaks can turn into full-blown plaques like those seen in the young American GIs of the Korean War. By the time we’re 40 or 50, they can start killing us off.

Atherosclerosis may start even before birth. Researchers found that the arteries of fetuses whose mothers had high LDL cholesterol levels were more likely to contain arterial lesions, suggesting atherosclerosis may not just start as a nutritional disease of childhood but one during pregnancy.

Childhood obesity and childhood diabetes have risen dramatically. Over recent decades, the number of American children considered to be overweight has increased by more than 100 percent. Children who are obese at age six seem more likely to stay that way, and 75 to 80 percent of obese adolescents may remain obese as adults.

Childhood obesity may be a powerful predictor of adult disease and death. Being overweight as a teenager was found to predict disease risk 55 years later. Such individuals may end up with twice the risk of dying from heart disease and a higher incidence of other diseases, including colorectal cancer, gout, and arthritis. Being overweight as a teen may in fact be an even more powerful predictor of disease risk than being overweight as an adult.


What are some of the most common nutrition mistakes people make when trying to eat healthier?

Researchers have found that a plant-based diet may help prevent, treat, or reverse some of our leading causes of death, including heart disease, type 2 diabetes, and hypertension. Studies of plant-based diets have shown, for example, 90 percent reductions in angina attacks within just a few weeks, and plant-based diet intervention groups have reported improved digestion, increased energy, and better sleep, and significant improvement in their physical functioning, general health, vitality, and mental health. Studies have also shown plant-based eating can improve not only body weight, blood sugar levels, and ability to control cholesterol, but also emotional states, including depression, anxiety, fatigue, sense of well-being, and daily functioning.


How can one diet do all that? Because plant-based foods contain more than 100,000 different potentially disease-preventing compounds—more specifically, more than 100,000 phyto-nutrients, phyto for the Greek word for plant. Blueberries have anthocyanins that may help with memory. Tomatoes are rich in the red pigment lycopene, which may help target heart disease and cancer, and ginger has gingerols that may help with hypertension. Intake of citrus has been associated with reduced stroke risk perhaps thanks to its phytonutrient hesperidin, which appears to increase blood flow throughout the body, including the brain. The list goes on. And we can’t just take these phytonutrients in a pill. When it comes to food, the whole is often greater than the sum of its parts. Beta carotene pills, for example, may actually increase cancer risk, as opposed to the whole carrot, which may lower our risk. (Who could swallow 100,000 pills a day anyway?)


Hundreds of phytonutrients have been found to have anti-inflammatory and antioxidant activity. Six months of consuming the phytonutrients curcumin, the bright-yellow pigment in turmeric, and quercetin, which is found naturally in such fruits and vegetables as red onions and grapes, appeared to decrease the number and size of polyps by more than half in patients with a hereditary form of colorectal cancer. And many phytonutrients may help block the formation of new blood vessels that feed tumors, and others appear to defend against toxic invaders. Researchers found that phytonutrients in such plant foods as fruits, vegetables, tea leaves, and beans can block the effects of dioxins in vitro, for example. Having phytonutrient levels in the bloodstream achieved by eating three apples a day or a tablespoon of red onion appeared to cut dioxin toxicity in half. As these phytonutrient effects lasted only a few hours, we should make sure to eat healthy foods at every meal.


Variety is the spice of life, so diversify your diet with a broad array of different vegetables, fruits, whole grains, nuts and seeds, and herbs and spices.

How can we ensure that we get enough micronutrients like vitamins and minerals in our diet, especially when following a vegan or plant-based diet?

For optimal health, we should eat a diversified plant-based diet of a variety of vegetables, fruits, whole grains, nuts and seeds, and herbs and spices, and, critically, include a regular, reliable source of vitamin B12.


Vitamin B12 is not made by plants or animals but by microbes that blanket the earth. In today’s sanitized, modern world, the water supply is commonly chlorinated to kill off any bacteria. So, while we don’t get much B12 in the water anymore, we don’t get much cholera, either, which is a good thing!


A regular, reliable source of vitamin B12 is critical for anyone eating a plant-based diet. Though deficiency for those starting out with adequate stores may take years to develop, the results of B12 deficiency can be devastating, with cases reported of paralysis, psychosis, blindness, and even death. Newborn infants of mothers who eat a plant-based diet and who fail to supplement may develop deficiency much more rapidly with disastrous results. Getting enough vitamin B12 is absolutely nonnegotiable for those centering their diets around plant-based foods.


  • For those under age 65, I recommend:
    • at least 2,000 mcg (µg) cyanocobalamin once each week, ideally as a chewable, sublingual, or liquid supplement taken on an empty stomach
    • or at least 50 mcg daily of supplemental cyanocobalamin (you needn’t worry about taking too much)
    • or servings of B12-fortified foods three times a day (at each meal), each containing at least 190% of the Daily Value listed on the nutrition facts label (based on the new labeling that started January 1, 2020—the target is 4.5 mcg three times a day)
  • Those over 65 years of age should take at least 1,000 mcg (µg) cyanocobalamin every day.

Instead of taking B12 supplements, it is possible to get sufficient amounts from B12-fortified foods for those age 65 and under, but we would have to eat three servings a day of foods each providing at least 25 percent of the Daily Value (on the Nutrition Facts label), with each serving eaten at least four to six hours after the last. For B12-fortified nutritional yeast, for example, two teaspoons three times a day would suffice. For most of us, though, it would probably be cheaper and more convenient to just take a supplement. Our fellow great apes get all the B12 they need eating bugs, dirt, and feces, but I’d suggest supplements instead!

How can we better focus on prevention of infectious diseases like COVID-19, particularly through nutrition and lifestyle?

The healthier we are, the stronger our immune system may be able to battle against viral infections. I’ve discussed how plant-based eating benefits us in countless ways—from helping to prevent, treat, or even reverse the progression of some of our leading causes of death to improving our vitality, mental health, physical functioning, emotional states, and much more.


Adhering to just four simple healthy lifestyle factors can have a strong impact: not smoking, not being obese, getting a half hour of daily exercise, and eating healthier—defined as consuming more fruits, veggies, and whole grains, and less meat. Those four factors alone were found to account for 78 percent of chronic disease risk. If you start from scratch and manage to tick off all four, you may be able to wipe out more than 90 percent of your risk of developing diabetes, more than 80 percent of your risk of having a heart attack, cut by half your risk of having a stroke, and reduce your overall cancer risk by more than one-third. For some cancers, like our number-two cancer killer, colon cancer, up to 71 percent of cases appear to be preventable through a similar portfolio of simple diet and lifestyle changes.

What are some of your current projects and initiatives in the field of health and nutrition?

I’m pleased to share that after three years of researching, writing, and reviewing thousands of research papers in the medical literature, I’ve just turned in the manuscript of my latest book. In How Not to Age, I explain how diet can regulate every one of the most promising strategies for combating the effects of aging. We don’t need Big Pharma to keep us feeling young―we already have the tools. I break down the science of aging and chronic illness and explain how to help avoid the diseases most commonly encountered in our journeys through life.

How can we improve access to healthy foods for everyone, especially for those with low income or in rural areas?

I’m heartened by the work of nonprofit organizations and community centers that take this on. Food deserts, food insecurity, and limited access to healthful and fresh plant-based foods are all terrible realities, and I encourage everyone to support their local food banks.

How can we raise awareness of the connection between animal agriculture, the environment, and health?

In November 2019, more than 11,000 scientists from 150 countries clearly and unequivocally declared that our planet is facing a climate emergency. The glaciers are melting, oceans are getting hotter and more acidic, sea levels are rising, and we’re experiencing greater numbers of extreme weather events. Fossil fuel use has been going up, but so has per capita meat consumption. Does what we eat play in role in climate change? Which diet has the least impact on the environment?


A plant-based diet may not only be optimal for our personal health, but for the health of our planet, too. The least healthy foods tend to cause the worst environmental impact, while the foods with the most nutrition just so happen to be the foods that cause the lowest greenhouse gas emissions.


Indeed, a systematic review found that eating a completely plant-based diet may be the optimal diet for the environment. Diets that include meat require about 3 times more water, 13 times more fertilizer, more than twice the energy, and 40 percent more pesticides than those that don’t. Looking at the total environmental impact of omnivorous versus vegetarian versus vegan diets—that is, looking not only at global warming, but also ocean acidification, agricultural run-off, smog, ecotoxicity of the water and soil, and direct human toxicity of the air we breathe, the water we drink, and the soil in which we grow our food—eating eggs and dairy may be 9 times worse than plants, and eating eggs, dairy, and meat may be 17 times worse than sticking to plant foods.


Unhealthy diets cause more death and disease than smoking, more than unsafe sex, and more than alcohol, drug, and tobacco use combined. We can address both human health and climate crises at the same time by increasing consumption of whole plant foods and substantially reducing our consumption of meat, eggs, and dairy. We can start in our own kitchens, today.

How can we as a society improve collaboration between health experts and government agencies to improve the health and wellbeing of the population?

We can’t sit back and wait for the powers that be to read our minds and make positive and lasting changes. We need to get active and speak up for ourselves, our families, and our communities, both local and global.


In conclusion, we would like to extend our heartfelt gratitude to Dr. Michael Greger for his valuable insights and commitment to providing us with a better understanding of the benefits

of a plant-based diet and its impact on our health. Dr. Greger’s extensive research and experience have provided us with valuable advice that we can incorporate into our daily lives.

We would like to personally thank you, Dr. Greger, for taking the time to share your valuable insights and experiences with us. We hope that this interview has helped our readers learn

more about how they can improve their diet to lead a healthier life.


Thank you for your time.

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