Have you ever wondered if there’s a natural way to lower your high blood pressure, guard against Alzheimer's, lose weight, and feel better? Well as it turns out there is. Michael Greger, M.D. FACLM, founder of NutritionFacts.org, and author of the instant New York Times bestseller “How Not to Die” celebrates evidence-based nutrition to add years to our life and life to our years.

New Research on the Optimal Diet

We constantly see new diets being touted. What does the research tell us about which is best?

This episode features audio from What Is the Optimal Diet?, The Weight Loss Program that Got Better with Time, and CHIP: The Complete Health Improvement Program. Visit the video pages for all sources and doctor’s notes related to this podcast.


Welcome to the Nutrition Facts podcast.  I’m your host Dr. Michael Greger.  I am thrilled that you have decided to join me today.  Because the more I learn about latest nutrition research – the more convinced I am that this information can make a real difference in all of our lives.  And I like nothing better – than sharing it with you. 

I’m on a year-long deep dive into the science of obesity for my next book (How Not to Diet). I’m so excited about all I’m learning, and can’t wait to share all the findings with you.  Today, I am happy to report a bit of what I’ve learned about the optimal diet.  As it turns out, the most well-published community-based lifestyle intervention in the medical literature is also one of the most effective.

England has been keeping mortality statistics since 1665, when yes, one person fell down some stairs and died, but in that week, nearly 4,000 people died of the plague.

Today, the modern plague is heart disease, the #1 killer of men and women, but it wasn’t always this way. If you dig back into those old statistics, by the middle of last century, heart disease was already killing off 5 to 10% of the population. But it was practically unknown at the beginning of the 20th century. Check out “The Natural History of Coronary [heart] Disease” just in the 1920s and 30s, skyrocketing 10-fold in men, and the same in women. What was going on? A clue could be found if you split people up by socioeconomic class. It was the richest folks who had up to triple the heart disease as the poorest. Maybe it had something to do with their rich diets. You don’t know, until you put it to the test, and in doing so, discover the natural cure of coronary heart disease—discovered decades ago by Pritikin, a plant-based diet and lifestyle program; followed by Dr. Dean Ornish, and then Esselstyn at the Cleveland Clinic. But how many know of the name Hans Diehl?

Dr. Diehl was the first Director of Research at the Pritikin Center back in 1976. He was “inspired” by the amazing results they were getting at the Pritikin Center, amazing results like that of a certain Grandmother Greger. But he “recognized the limitations of [live-in] residential programs,” including their cost…and the ‘artificial’ living environment that made sustaining the behaviors more difficult [when patients] returned [back home].” So, Diehl developed the “CHIP” program “as an affordable 30-day lifestyle intervention” to be delivered in a community setting.

Ten years in, Esselstyn encouraged Hans to publish their results in the American Journal of Cardiology. “Coronary Risk Reduction Through [a] Community-Based Lifestyle Intervention,” famously starting out with a quote from the pioneer of coronary bypass surgery, describing it as “only a palliative treatment.” The only way we’re going to stop the epidemic is through prevention.

We know “vigorous cholesterol lowering can slow, arrest, or even reverse atherosclerosis.” But, it only works if you do it. Live-in programs work because you can control people’s diets, but they’re expensive, and people may go back home to toxic food environments. So, how about instead of them coming to you, you go to them in the community?

The original program was 16 evening sessions over four weeks, “the major focus [being to encourage participants to adopt the ‘Optimal Diet.’” They also encouraged people to walk a half-hour a day. But, most importantly, center their diet around whole plant foods. Now, that was the optimal: whole food plant-based. But, the program isn’t dogmatic, just encouraging people “to move along the spectrum” towards incorporating more whole healthy plant foods into their diets. They didn’t provide meals, just advice and encouragement, and…four weeks, later got an average weight loss of about six pounds, blood pressures went down about six points, and their LDL, bad cholesterol, down between 16 and 32 points, and fasting blood sugars dropped as well.

“Often, participants were able to decrease or discontinue antidiabetic, [cholesterol-lowering, and blood pressure-lowering] medication,” making their findings even more extraordinary. Better numbers on fewer drugs.

Live-in programs, like Pritikin and McDougall, are great in that you can optimize the “clinical benefits.” But, they can cost thousands of dollars—in addition to missing work—whereas CHIP is cheap, and they’re living at home. So, it’s not like they’ve been spoonfed some perfect diet for a few weeks at some spa, and then go back to their cupboards of cookies. CHIP is a free-living program, teaching people how to eat and stay healthy within their home environments.

Well, at least, that’s the theory. These remarkable results were after just four weeks in the program. “The true test…will be to what extent people adhere to their new lifestyle and sustain their health benefits” weeks, months, or even more than a year later, which we’ll explore, next.

In our next story we discover how the CHIP program has attempted to take the pioneering lifestyle medicine work of Pritikin and Ornish and spread it out into the community.

The CHIP program may be the most “well-published community-based lifestyle intervention…in the medical literature. And, one of the most effective, with “clinical changes…approaching that achieved in live-in residential lifestyle programs.”

Encouraging people to transition toward a more whole food, plant-based diet achieved blood pressure benefits that were “greater than those reported [with] the DASH diet and comparable with the results” in blood pressure-lowering drug trials. If we’re going to reverse the worldwide chronic disease epidemic, though, we’ve got to scale this thing up. So, to make the CHIP program “more accessible to a wider audience, each of Hans Diehl’s live presentations was videotaped.” Then, you could just have a volunteer facilitator get people in a room and watch the videos, and help foster discussion. When it comes to safe, simple, side effect-free solutions, like a healthier diet and lifestyle, you don’t need to wait for a doctor to show up and give a lecture. Yeah, but does it work?

Those that came in with diabetic-level fasting blood sugars, about one in three left with non-diabetic-level fasting blood sugars, and all they did was empower people with knowledge. Just encouraging people to move toward a whole food, plant-based diet led to these remarkable benefits.

How about the effectiveness of this “volunteer-delivered lifestyle modification program” on 5,000 people? Same kind of “significant reductions” in weight, blood pressure, cholesterol, triglycerides, and blood sugars. Most studies giving “dietary advice to free-living subjects” can be expected to reduce total cholesterol by only about 5%. But, hey, a sustained reduction of even 1% may result in “a 2-3% reduction in the incidence of…heart disease.” So, on a population scale, “even small” differences matter. But, put thousands of people through just one month of CHIP, and get an 11% drop on average—and up to a nearly 20% drop among those who need it most.

Yeah, but do they maintain their healthy habits? I mean, doctors can’t even get most people to keep “taking a [single] pill once a day.” How effective is a volunteer-led video series going to be at getting people to maintain a change of eating habits? Researchers looked at the CHIP data to find out. How were participants still doing 18 months later? Most were able to maintain their reductions of meat, dairy, and eggs, though some of the junk food started to slip back in. And, their fruit and veggie consumption dipped, though not back to baseline. But, here’s the huge shocker. Even though they were explicitly told to eat as much as they wanted—no calorie or carb counting, no portion control—just by being informed about the benefits of centering their diets more around whole plant foods, by the end of the six-week program, they were eating, on average, about 339 fewer calories a day without even trying. Instead of eating less food, they were just eating healthier food.

Okay. But, this was right at the end of the 6-week program, when they were all jazzed up. Where were they 18 months later? Anyone familiar with weight-loss studies knows how this works; you can excite anyone in the short-term to lose weight, using practically any kind of diet. But then, six months later, a year later, they tend to gain it all back, or even more. Yeah, they were eating about 300 calories less a day during the program, but 18 months later, were only eating about 400 calories less. Wait, what kind of diet can work even better the longer you do it? A whole food, plant-based diet. Many weight loss programs restrict calorie intake by “limiting portion sizes, which often results in hunger and dissatisfaction,…contributing to low compliance and weight regain.” But the “satiety-promoting,” all-you-care-to-eat, “plant-based, whole food dietary approach” may be the secret weapon toward sustainable weight loss.

In our final story today we discover how a community-based education program is educating physicians and patients alike about the power of nutrition as medicine. 

“The best kept secret in medicine is that, given the right conditions, the body can sometimes heal itself.” And: “When it comes to cardiovascular disease, there is no substitute for nutritional excellence.” So, Ornish, Pritikin, Barnard, Esselstyn—all the great names in evidence-based nutrition. But, how many have heard about the CHIP program (the Coronary Health Improvement Project), a volunteer-run community-based education program “educating physicians and patients alike, about the power of nutrition as medicine is perhaps the best investment we can make in the fight against heart disease.” More effective, cheaper, safer. And, what are the side effects? Improved overall health, and not just physical health.

“Lifestyle change programs, such as CHIP, aimed at improving physical health behaviors can likewise have a profound effect on mental health.” Based on studies of thousands of individuals who went through the CHIP program, there were significant improvements in a number of “sleep or stress disorders,” like sleeping restlessly, not sleeping at all, stress, upset, fear, and depression. Here are the numbers; most of these cut in half. All highly significant findings. The question is why?

Well, “[t]he psychological well-being of the CHIP participants might have been positively affected by increasing feelings of empowerment, making strides toward reducing their body weight, and improving other health indicators.” As they start eating better and making strides, feelings of despair and failure “may be replaced by a growing sense of accomplishment, increased social support, and a new sense of hope.” Or, they may just be physically feeling better. If your diabetes goes away, that’s reason enough to perk you up.

While these before-and-after results looked great, what was missing? Right, a control group. Now, you say, “Wait; they each acted as their own control, before and after.” Ah, you’re forgetting about “the Hawthorne effect”. Remember? Just being in a study under observation can affect people’s behavior. So, if they put you on a scale, weigh you, and say they’re going to weigh you again in six months, people may consciously—or unconsciously—just eat better on their own, even if they’re not told to do anything special. So, how much of these improvements would have happened without the CHIP program?

Yeah, it’s great that you can take a thousand people and markedly reduce their risk-factor profiles for our leading killer in just four weeks—regardless. But, to know exactly what role healthy eating and living advice can play, you need to… put it to the test, by performing randomized controlled trials.

And, as expected, there were small improvements even in the control group. But, “for almost all variables, the CHIP intervention group showed significantly greater improvements”—so much so as to have “the potential to dramatically reduce the risks associated with common chronic diseases in the long term.” Ironically, CHIP was so successful in this city of Rockford, Illinois that dozens of restaurants started offering special plant-based menu options. So, the control group might have been sneaking in some healthier meals too.

Okay, but what about the mental health improvements? A randomized controlled trial, and…”those in the CHIP group showed significantly greater improvements in physical functioning,…pain, general health perceptions, vitality, social functioning, and emotional and mental health. For example, significant improvements, particularly in mild to moderate depression, compared to the control group. And, not just right after the program ended, but six months later.

So, the CHIP acronym started out as the Coronary Health Improvement Project, but as study after study “showed the efficacy of the intervention in addressing other chronic diseases, such as type 2 diabetes and even depression,” it has since been renamed…the Complete Health Improvement Program.”

As Hans Diehl—the founder of CHIP—explains, “We as a society are largely at the mercy of powerful and manipulative marketing forces that basically tell us what to…eat….Everywhere we look, we’re being seduced to the ‘good life’ as marketers define it,…but this so-called ‘good life’ has produced in this country an avalanche of morbidity and mortality”—disease and death….What he’d like to see in America is not this so-called ‘good life,’ but the ‘best life’…a simpler lifestyle…characterized by eating more whole plant foods,” in other words, “foods-as-grown.”

We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition.  Go to nutrition facts.org forward 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 of the sources we cite for each of these topics.

Be sure to check out my new “How Not to Die Cookbook.”  It’s beautifully designed, with more than 100 recipes for delicious and nutritious, life-saving, plant-based meals, snacks, and beverages.  All proceeds I receive from the sales of all my books goes to charity.

NutritionFacts.org is a nonprofit, 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.

Thanks for listening to Nutrition Facts.  I’m your host, Dr. Michael Greger.

This is just an approximation of the audio content, contributed by Becky Boyle.

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