Did you know that one in five deaths is connected in a straight line to diet? That means we have the power to make changes to improve our health, if we know better. And no book makes a better case for this than How Not to Die by Dr. Michael Greger.
The book was republished in 2025 in an updated and revised edition. Its first half is dedicated to studying how eating more plants can reduce our odds of dying from the 15 leading causes of death in North America. Each chapter covers a cluster of diseases: brain diseases including Alzheimer’s, heart disease (our number one killer), liver disease, diabetes, and more.
Yes, these are different causes of death, but they are not silos. They’re deeply connected, and there are themes that cut across every chapter. What follows are my 10 personal takeaways from studying the first part of the book in depth. These are the patterns I’ve seen. If you’ve tried reading the book and felt overwhelmed, read some of it and abandoned it, or if you’ve just heard the buzz and wondered what the big deal is, I hope this helps you decide whether you want to dig in.
Note: This is about Part I, which concerns the causes of death. Part II is about the elements of the Daily Dozen we should enjoy daily to fight back. Learn more here.
Wondering whether to read the 2025 edition? Check out my YouTube video on the topic.
1. The body heals itself, if you let it
If there’s only one takeaway you get from this book, this should be it: the human body has an extraordinary capacity to heal itself, if only we let it. But unfortunately, we don’t. As Dr. Greger likes to say, it’s like whacking your shin on the table several times a day and wondering why it hurts.
We eat three meals a day (with snacks in between) loaded with fat, sugar, and salt, all of which are known to injure our capacity to build a healthy body. It doesn’t have to be like that. The most striking example is the story of Dr. Greger’s grandmother. At 65, she was wheelchair-bound and sent home to die with terminal heart disease. She heard about the Pritikin Center, attended an intensive lifestyle rehab program, and after just a few weeks she was able to walk again. She lived for three more decades in good health, largely thanks to a plant-based diet. That left a strong impression on little Michael.
But it’s not just an anecdote. Classic research has shown that when heart disease patients were put through a plant-based diet program, hoping it would at least prevent the disease from worsening, the disease actually started to reverse itself. After just a few weeks, arteries were opening up, blood was flowing more freely, and people were feeling better quickly.
Dr. Greger’s main point: there is no bad time to start eating better. Our bodies are just waiting for the chance to get to work.
2. Different diseases have common dietary root causes
Conventional medicine works in silos. It treats heart disease, diabetes, Alzheimer’s, and cancer like separate problems, with different specialists, different drugs, different departments of the hospital that, at best, send each other some notes.
But when we look at the evidence documenting the causes of these different diseases, the same culprits come up over and over:
- Cholesterol and saturated fats (essentially euphemisms for animal products).
- Cooking byproducts like TMAOs and AGEs that form when we cook high-fat, high-protein animal foods.
- The calorie density problem that fuels the obesity epidemic, since animal products pack far more calories per volume than plants.
And perhaps most importantly, there’s the opportunity cost. Every bite we take of one kind of food means one fewer bite of another. When we fill our plate with meat, dairy, and eggs, that’s space that can’t be used by beans, vegetables, and whole grains. We have limited real estate on the plate and a limited calorie budget each day. What we choose to put in our mouth has consequences in both directions.
3. Powerful actors benefit from the status quo
This theme comes back chapter after chapter, and it angers me. Many chapters in Part One of How Not to Die mention the various industries that are deeply invested in – and benefit from – things staying just the way they are: the animal agriculture industry, pharma, medical equipment, fast food, and to some extent even physicians themselves. Of course, doctors want nothing more than to see their patients feel better. But their skillsets and incentives are aligned with prescription drugs and surgeries, not nutrition counseling. Most don’t even receive nutrition training.
This is not to say that everyone in the medical industry is corrupt or that there’s a nefarious conspiracy. But the result is the same. Dietary solutions don’t get half the attention they deserve because they don’t have the same kind of power structure supporting them. The incentives just point the other way.
4. Conventional therapies often have marginal benefits and serious side effects
For each of the main causes of death and disability he covers, Dr. Greger acknowledges that conventional treatments exist: drugs, surgeries, procedures. But many are only marginally effective, focused on reducing symptoms rather than actually healing. You’re still whacking your shin on the table, but the drugs mask the pain. Oddly, that allows you to whack even harder.
The side effects can be serious. A memorable example: an Alzheimer’s drug that may cause massive brain bleeds, which seems a little counterproductive. Even statins, prescribed to one in four Americans, can cause significant side effects like constipation, muscle aches, and fatigue.
Sure, it might be a little inconvenient to learn how to make overnight oats with berries and nuts. It’s certainly less practical than grabbing a ready-made muffin and a sweet coffee drink. But there’s no brain fog associated with breakfast oats.
5. The damage starts shockingly early
This one hurts. Autopsy studies have shown that children as young as 10 years old have fatty deposits in their arteries, the beginnings of heart disease. In children!
Similarly unsettling facts arise across chapters. The processes that lead to disease (plaque buildup, cell mutations, chronic inflammation) happen silently for decades before there’s enough to trigger a doctor visit and eventually a diagnosis. Cancer cells form somewhat spontaneously in all of us, all the time, due to environmental pollutants, radiation, and random mutations. The question is: will the food we eat feed the tumors, or suppress them?
This idea reframes everything. Disease doesn’t strike randomly in middle age. It’s been building for decades, since childhood. The big difference is whether what we eat fans the flames or helps put out the fire.
6. It’s not just about the animal fat
Up to this point, we’ve mostly talked about the fat in animal products: cholesterol, saturated fat, even trans fats. (By the way, I thought trans fats were only human-made and that the ban had taken care of the problem. But trans fats are actually naturally occurring in many animal products, and those don’t have to be labeled on packages.)
Fats are significant, but Dr. Greger demonstrates that the problem goes a lot deeper. There’s a whole chapter on infections, including foodborne illnesses and the issue of endotoxins that ooze out of animal guts during slaughter (pretty gross). Then there’s antibiotic resistance: the superbugs we’re fighting in hospitals don’t primarily originate from doctors overprescribing antibiotics for kids’ ear infections. The real cause is the overuse of antibiotics in animal farming to promote growth and increase profits.
And then there’s pandemic risk. This one hits differently post-COVID. The 2025 edition reflects how much we’ve learned since 2015. Dr. Greger has been an expert on this topic for years, having published How to Survive a Pandemic in 2020 (itself a remix of his earlier Bird Flu). That’s a whole other dimension of the problem with animal products.
7. Plants are not only benign. They actively heal
This is the part of the book that gives me hope and energy. Plant foods don’t just “not hurt” compared to animal products. They actively heal. Fruits, vegetables, spices, and other plants contain antioxidants, fiber, and specific compounds with demonstrated healing properties. We’re talking ginger, saffron, turmeric, even good old cinnamon. And the superstar sulforaphane, conveniently found in my favorite vegetable, broccoli (and other cruciferous vegetables), which actively fights cancer cells.
Plants have low calorie density, so we can eat a ton of them without overloading our systems. The fiber doesn’t just help with digestion; it helps keep our blood vessels clean, feeds the gut microbiome, and generally supports good housekeeping in the body.
Plantwise Book Club members have framed it beautifully: eating lots of different plants means basically microdosing on healing compounds. And remember, nearly all pharmaceutical drugs were originally derived from plants. Why not go straight to the source?
8. Population and cohort studies tell a consistent story
Across cultures and continents, the pattern holds. Populations that eat plant-rich diets have greater longevity and better healthspan than those eating the standard Western diet. Think of the Blue Zones, regions where so many people live past 100 in good health, staying active and connected to their communities. Their diets are anchored in whole plants: beans, greens, vegetables from the garden. Home cooking, not fancy longevity hacks.
Dr. Greger draws on this population evidence throughout the book, including immigration studies. Individual studies can of course be debated, but when we zoom out and look at the big picture, there’s a very clear signal, and we shouldn’t ignore it.
9. There are no downsides to trying more plants
Here’s something Dr. Greger does that some of his critics find annoying but I quite appreciate. Sometimes he cites small studies and says, “Look, this was only 15 people,” or “This looked good but it happened in a Petri dish.” Those are not random or inconsistent studies. They reflect research that supports the bigger picture, pointing to mechanisms that explain the power of plant foods to fight disease, things we’ve also seen at scale in other studies.
Some people are bothered by this because they feel pressure to do everything perfectly or face shame for falling short. But consider the bigger context. When cancer patients have exhausted conventional options, they’re often offered experimental therapies that are promising but unproven, highly invasive, with terrible side effects that might even accelerate death. Not every patient says yes, but they’re glad to be offered the choice.
By contrast, Dr. Greger is suggesting that we complement our salads with broccoli sprouts or add half a teaspoon of cinnamon to our oatmeal. These are not silver bullets, and he doesn’t claim they are. But all signs point to these foods being helpful. And unlike the pharmaceutical industry, there’s no Big Broccoli or Big Spice Lobby to promote them. If people like Dr. Greger weren’t talking about it, we’d probably never hear about it at all.
Personally, I know I can’t do it all, but I’m glad to know, so I can squeeze in what makes sense in my life at any given time.
10. Exercise helps, but diet is probably more powerful
Dr. Greger is pro-exercise (he famously gives interviews while walking at his treadmill desk). But when it comes to the evidence, we have examples where diet alone has been compared to exercise alone, and to diet and exercise together. What we typically find is that exercise alone is good, but diet is better, and the combination makes the biggest difference.
The most detailed example concerns prostate cancer (if you have a prostate or love someone who does, I recommend checking it out in the book). But the point is not to skip exercise. It’s that if we’re going to prioritize one thing, we should start with the food.
Wrapping it up this summary of How Not to Die
Let me boil the 10 big ideas down to three sentences.
- Our major diseases share dietary root causes, largely driven by heavy consumption of animal products, including fats and other damaging factors, and the damage starts shockingly early.
- Conventional treatments exist but don’t truly heal, and powerful industries have every incentive to protect the status quo.
- Meanwhile, population and smaller studies consistently show that plants maintain and promote health and healing, the body repairs itself once we stop injuring it, and diet may matter even more than exercise, with no downside in trying.
Is How Not to Die a perfect book? Of course not. There are legitimate criticisms of the book and of Dr. Greger, as there should be for such an important work. But the bottom line for me is clear: there is tremendous evidence supporting a predominantly plant-based diet and reducing or eliminating our intake of animal products.
Small changes matter. Big changes matter more.
If you want to go deeper into How Not to Die with a group of plant-friendly folks who care about their health, you’ll love the Plantwise Book Club. We’ve just started our three-month deep dive into the book. Join us for core meetings on Zoom every two weeks, group co-reading sessions, and a fantastic online community. Start your free trial today!