Absorb what is useful, discard what is useless, and add what is specifically your own.
—Bruce Lee
In the mid-nineteenth century, a French physician named Stanislas Tanchou observed that cancer was becoming ever more prevalent in the fast-growing cities of Europe. The Industrial Revolution was charging ahead at full speed, changing society in unimaginable ways. He saw a connection between the two: “Cancer, like insanity, seems to increase with the progress of civilization.”
He was prescient. Eventually cancer, as well as heart disease, type 2 diabetes, and dementia (along with a few others), became collectively known as “diseases of civilization,” because they seemed to have spread in lockstep with the industrialization and urbanization of Europe and the United States.
This doesn’t mean that civilization is somehow “bad” and that we all need to return to a hunter-gatherer lifestyle. I would much rather live in our modern world, where I worry about losing my iPhone or missing a plane flight, than endure the rampant disease, random violence, and lawlessness that our ancestors suffered through for millennia (and that people in some parts of our world still experience). But even as modern life has helped extend our lifespans and improve living standards, it has also created conditions that conspire to limit our longevity in certain ways.
The conundrum we face is that our environment has changed dramatically over the last century or two, in almost every imaginable way—our food supply and eating habits, our activity levels, and the structure of our social networks—while our genes have scarcely changed at all. We saw a classic example of this in chapter 6, with the changing role that fructose has played in our diet. Long ago, when we consumed fructose mainly in the form of fruit and honey, it enabled us to store energy as fat to survive cold winters and periods of scarcity. Fructose was our friend. Now fructose is vastly overabundant in our diet, too much of it in liquid form, which disrupts our metabolism and our overall energy balance. We can easily take in far more fructose calories than our bodies can safely handle.
This new environment we have created is potentially toxic with respect to what we eat (chronically, not acutely),[*] how we move (or don’t move), how we sleep (or don’t sleep), and its overall effect on our emotional health (just spend a few hours on social media). It’s as foreign to our evolved genome as an airport would have been to, say, Hippocrates. That, coupled with our newfound ability to survive epidemics, injuries, and illnesses that formerly killed us, has added up to almost a defiance of natural selection. Our genes no longer match our environment. Thus, we must be cunning in our tactics if we are to adapt and thrive in this new and hazardous world.
This is why we have navigated through the preceding two hundred pages about our objective and our strategy. To figure out what to do, we need to know our adversary inside and out, the way Ali knew Foreman. By now, we should understand our strategy fairly well. Hopefully, I have at least given you some understanding of the biological mechanisms that help predispose us to certain diseases, and how those diseases progress.
Now it’s time to explore our tactics, the means and methods by which we will try to navigate this strange and sometimes perilous new environment. How are we going to outlive our old expectations and live our best Bonus Decades? What concrete actions can we take to reduce our risk of disease and death and improve the quality of our lives as we age?
In Medicine 3.0, we have five tactical domains that we can address in order to alter someone’s health. The first is exercise, which I consider to be by far the most potent domain in terms of its impact on both lifespan and healthspan. Of course, exercise is not just one thing, so I break it down into its components of aerobic efficiency, maximum aerobic output (VO2 max), strength, and stability, all of which we’ll discuss in more detail. Next is diet or nutrition—or as I prefer to call it, nutritional biochemistry. The third domain is sleep, which has gone underappreciated by Medicine 2.0 until relatively recently. The fourth domain encompasses a set of tools and techniques to manage and improve emotional health. Our fifth and final domain consists of the various drugs, supplements, and hormones that doctors learn about in medical school and beyond. I lump these into one bucket called exogenous molecules, meaning molecules we ingest that come from outside the body.
In this section I will not be talking much about exogenous molecules, beyond those that I have already mentioned specifically (e.g., lipid-lowering drugs, rapamycin, and metformin, the diabetes drug that is being tested for possible longevity effects). Instead, I want to focus on the other four domains, none of which were really covered, or even mentioned, in medical school or residency. We learned next to nothing about exercise, nutrition, sleep, or emotional health. That may be changing, slowly, but if some doctors understand these things today, and are actually able to help you, it’s likely because they have sought out that information on their own.
At first glance, some of our tactics might seem a bit obvious. Exercise. Nutrition. Sleep. Emotional health. Of course, we want to optimize all of these. But the devil (or, to me, the delight) is in the details. In what way(s) should we be exercising? How are we going to improve our diet? How can we sleep longer and better?
In each of these cases, while the broad-brush goals are clear, the specifics and the nuances are not. Our options are almost infinite. This requires us to really drill down and figure out how to come up with an effective tactical game plan—and to be able to change course as needed. We have to dig deeper to get beyond the obvious.
What constitutes an effective tactic?
One way I like to explain this is through the example of car accidents, which also happen to be a minor obsession of mine. They kill far too many people across all age groups—one person every twelve minutes, according to the National Highway Traffic Safety Administration—yet I believe that a fair number of these deaths could be prevented, with the proper tactics.
What can we do to reduce our risk of dying behind the wheel? Is it even possible to avoid car accidents, when they seem so random?
The obvious tactics we already know about: wear a seat belt, don’t text and drive (seemingly difficult for many people), and don’t drink and drive, since alcohol is a factor in up to a third of fatalities. Automotive fatality statistics also reveal that almost 30 percent of deaths involve excessive speed. These are helpful reminders, but not really surprising or insightful.
Recognizing the danger points is the first step in developing good tactics. I had almost automatically assumed that freeways would prove to be the deadliest place to drive because of the high speeds involved. But decades’ worth of auto accident data reveal that, in fact, a very high proportion of fatalities occur at intersections. The most common way to be killed, as a driver, is by another car that hits yours from the left, on the driver’s side, having run a red light or traveling at high speed. It’s typically a T-bone or broadside crash, and often the driver who dies is not the one at fault.
The good news is that at intersections we have choices. We have agency. We can decide whether and when to drive into the crossroads. This gives us an opportunity to develop specific tactics to try to avoid getting hit in an intersection. We are most concerned about cars coming from our left, toward our driver’s side door, so we should pay special attention to that side. At busy intersections, it makes sense to look left, then right, then left again, in case we missed something the first time. A high school friend who is now a long-haul truck driver agrees: before entering any intersection, even if he has the right of way (i.e., a green light), he always looks left first, then right, specifically to avoid this type of crash. And keep in mind, he’s in a huge truck.
Now we have a specific, actionable tactic that we can employ every time we drive. Even if it can’t guarantee that we are 100 percent safe, it reduces our risk in a small but demonstrable way. Better yet, our tactic has leverage: a relatively minor effort yields a potentially significant risk reduction.
We approach our tactics the same way, zooming in from the vague and general to the specific and targeted. We use data and intuition to figure out where to focus our efforts, and feedback to determine what is and isn’t working. And seemingly small tweaks can yield a significant advantage if compounded over time.
My car accident analogy may seem like a bit of a tangent, but it’s really not that dissimilar from the situation we face in our quest for longevity. The automobile is ubiquitous in our society, an environmental hazard that we need to learn to live with. Similarly, in order to stay healthy as we grow older, we must learn to navigate a world that is filled with ever more hazards and risks to our health. In this third and final section of the book, we will explore various methods by which we can mitigate or eliminate those risks, and improve and increase our healthspan—and how to apply them to each unique patient.
Our two most complex tactical domains are nutrition and exercise, and I find that most people need to make changes in both—rarely just one or the other. When I evaluate new patients, I’m always asking three key questions:
a. Are they overnourished or undernourished? That is, are they taking in too many or too few calories?
b. Are they undermuscled or adequately muscled?
c. Are they metabolically healthy or not?
Not surprisingly, there is a high degree of overlap between the overnourished camp and those with poor metabolic health, but I’ve taken care of many thin patients with metabolic problems as well. Almost always, though, poor metabolic health goes along with being undermuscled, which speaks to the interplay between nutrition and exercise.
We will talk about all these different situations in much more detail, but briefly, this is why it’s important to coordinate between all the different tactical interventions we employ. For example, with a patient who is overnourished, we want to find a way to reduce their caloric intake (there are three ways to do this, as you’ll see in chapter 15). But if they are also undermuscled, which is common, we want to be careful to make sure they are still getting enough protein, since the goal is not weight loss but fat loss coupled with muscle gain. It can get complicated.
None of our tactical domains is fully separate from the others. In chapter 16, for example, we will see how sleep has a tremendous effect on our insulin sensitivity and our exercise performance (and our emotional well-being, as well). That said, with most patients I devote a great deal of attention to their fitness and their nutrition, which are closely linked. We rely heavily on data in our decision-making and developing our tactics, including static biomarkers such as triglycerides and liver function tests, as well as dynamic biomarkers such as oral glucose tolerance tests, along with anthropometric measures such as data on body composition, visceral adipose tissue, bone density, and lean mass.
Much of what you are about to read mirrors the discussions I have with my patients every single day. We talk about their objectives, and the science underpinning our strategy. When it comes to specific tactics, I give them direction to help them create their own playbook. I almost never write out a prescription for them to follow blindly. My goal is to empower them to take action to fix their fitness, nutrition, sleep, and emotional help. (Note that for most of these things, I don’t actually even need a prescription pad.) But the action part is their responsibility; not much of this stuff is easy. It requires them to change their habits and do the work.
What follows is not a step-by-step plan to be followed blindly. There is no blanket solution for every person. Providing very granular exercise, dietary, or lifestyle advice requires individual feedback and iteration, something I can’t safely or accurately accomplish in a book. Rather, I hope you will learn a framework for managing your movement, nutrition, sleep, and emotional health that will take you much further than any broad prescription for how many grams of this or that macronutrient every single person on earth must eat. I believe this represents the best we can do right now, on the basis of our current understanding of the relevant science and my own clinical experience (which is where the “art” comes in). I’m constantly tinkering, experimenting, switching things up in my own regimen and in that of my patients. And my patients themselves are constantly changing.
We are not bound by any specific ideology or school of thought, or labels of any kind. We are not “keto” or “low-fat,” and we do not emphasize aerobic training at the expense of strength, or vice versa. We range widely and pick and choose and test tactics that will hopefully work for us. We are open to changing our minds. For example, I used to recommend long periods of water-only fasting for some of my patients—and practiced it myself. But I no longer do so, because I’ve become convinced that the drawbacks (mostly having to do with muscle loss and undernourishment) outweigh its metabolic benefits in all but my most overnourished patients. We adapt our tactics on the basis of our changing needs and our changing understanding of the best science out there.
Our only goal is to live longer and live better—to outlive. To do that, we must rewrite the narrative of decline that so many others before us have endured and figure out a plan to make each decade better than the one before.
* Acutely, our food supply is safer than ever thanks to refrigeration and advances in food processing, and regulations that prevent toxic substances from being used in food. Chronically, not so much (see chapter 15).