I was soon recommending it to the athletes I coached, including Ryan Bolton, who was on the U.S. Olympic Triathlon team. Since 1995 I have written four books on training for endurance athletes and have described and recommended the Paleo Diet in each of them. Many athletes have told me a story similar to mine: they have tried eating this way, somewhat skeptically at first, and then discovered that they also recovered faster and trained better.
“Exercise”: A Funny Idea to Hunter-Gatherers
In the late 1980s, the world community became increasingly alarmed at the shrinking tropical rain forest in the Amazon basin (due to clear-cut logging, mining, and industrialization). Politicians and environmentalists launched a host of programs to curb this deforestation and even brought native Amazon Indians to environmental conferences in New York City. At one such conference, a group of Indians came across joggers exercising in Central Park—and found this concept absolutely hilarious. That adults would run for no apparent reason was comically absurd to these practical hunters. In their tropical forest home, every movement had a function and a purpose. What could possibly be gained by running to no destination, with no predators or enemies to escape from, and with nothing to capture?
Physical Fitness: Naturally, and with No Exercise Programs
The mind-set of these Amazonian Indians was undoubtedly very similar to that of any of the world’s hunter-gatherers. They got plenty of exercise simply by carrying out the day’s basic activities—finding food and water, building shelters, making tools, and gathering wood. These activities were more than enough to allow them to develop superb physical fitness. Strength, stamina, and good muscle tone were the natural by-products of their daily routine.
Our Stone Age ancestors worked hard or they didn’t eat. Sustained labor wasn’t necessary every day; periods of intense exertion generally alternated with days of rest and relaxation. But the work was always there, an inevitable fact of life. There were no retirement plans, no vacations, and definitely no labor-saving devices. Everybody, except for the very young or the very old, helped out. And their daily efforts were astonishing. The amount of physical activity performed by an average hunter-gatherer would have been about four times greater than that of a sedentary office worker—and about three times greater than anybody needs to get the health benefits of exercise. An office worker who jogged 3 miles a day for a whole week would use less than half the energy of an average hunter-gatherer, such as the !Kung people of Africa. !Kung men on average walk 9.3 miles per day; the women average 5.7 miles per day. As you may expect, all this walking and regular physical activity pays off with high levels of physical fitness for everyone. In fact, my research team has shown that the average aerobic capacity of the world’s hunter-gatherers and less Westernized peoples is similar to that of today’s top athletes.
Exercise and Obesity
There are few physicians or health professionals who would argue that exercise shouldn’t accompany dietary programs.
Most of the scientific experiments that have monitored weight loss with and without exercise programs have shown that moderate exercise (20 to 60 minutes of walking or jogging five times a week) doesn’t help you lose weight any faster—but it is very effective in helping you keep the extra pounds off over the long term
Why Exercise by Itself Doesn’t Promote Weight Loss
The idea of exercising the extra pounds away—if this is your only means of weight loss—is not terribly practical. Exercise combined with diet is no more effective than diet alone in causing weight loss. How can this be? The answer is a scientific equation: to lose a pound of fat, you need to achieve a caloric deficit of 3,500 calories.
Imagine that a mildly obese woman, weighing 154 pounds, would like to lose 30 pounds, or 105,000 calories, by walking or jogging for 3 miles (forty-five minutes) a day. On days when she walks or jogs, she expends 215 additional calories (compared to the 80 calories she expends for that same forty-five-minute period on other days). The 3-mile walk/jog causes a net deficit of 135 calories—not a lot, considering the amount of work she’s doing. At this rate, it will take her 26 days to lose 1 pound and 780 days (more than 2 years) to lose 30 pounds. Most dieters simply don’t have the patience to wait that long. (Frankly, most of us need the encouragement of seeing the scale change more rapidly to help us keep up the good work. Otherwise, it’s easy to become discouraged and give up.)
Experiments by my colleague Dr. Joe Donnelly and coworkers at the University of Nebraska at Kearney, and by Dr. David Nieman at Appalachian State University in Boone, North Carolina, have demonstrated that diet alone is just as effective as diet plus exercise in causing weight loss.
The real benefit from exercise for weight loss comes not from the modest caloric deficit that it may create, but from its ability to keep weight off once it has been lost. Dr. Rena Wing of Brown University School of Medicine in Providence, Rhode Island, reviewed a large number of exercise trials in which participants either dieted only or dieted and exercised. Reporting on the participants a year later, Dr. Wing noted, “In all of the long-term randomized trials reviewed, weight losses at follow-up were greater in diet plus exercise than in diet only.”
Why Should You Exercise?
Regular exercise, though, is great for your body. One major benefit: it improves your insulin metabolism. As I’ve discussed earlier in this book, many overweight people are insensitive to insulin, a hormone secreted by the pancreas that aids the entry of glucose from the bloodstream into all cells of the body, including the muscle cells. When muscle cells become insensitive to insulin, the pancreas responds by secreting more insulin. This, in turn, raises the normal level of insulin in the bloodstream. The resulting elevation of blood insulin levels, called “hyperinsulinemia,” is the underlying cause of the metabolic syndrome diseases. Insulin is a master hormone that influences many other critical cellular functions. An elevated level of insulin in the bloodstream encourages fat deposition and the development of obesity.
Regular exercise has been shown in clinical studies to improve the muscles’ sensitivity to insulin and to lower the level of insulin in the bloodstream. In other words, although exercise alone does not cause the large caloric deficits needed for weight loss, it sets the metabolic stage for weight loss to occur by improving your insulin metabolism—as long as you cut back on calories.
Improving your insulin sensitivity may also reduce your appetite by preventing the large swings in blood sugar levels that are a direct consequence of too much insulin secretion. When you eat a carbohydrate-heavy meal, digestive enzymes convert most of the carbohydrate to glucose, which then enters the bloodstream. Normally, the pancreas secretes just the right amount of insulin to help convert glucose into muscle and other cells of the body and to help keep the blood sugar level on an even keel. However, when your muscles are resistant to insulin’s action and the pancreas must secrete extra insulin, this drives the blood glucose level even lower. This reduction in blood sugar, called “hypoglycemia,” makes you hungry—even if you’ve just eaten a large meal. Exercise can help break this vicious cycle by making the muscles more sensitive to insulin.
Exercise and Blood Lipids
Medical evidence suggests that exercise training alone has little or no effect on the LDL blood cholesterol level. However, it can improve the total/HDL cholesterol ratio and reduce your risk of heart disease by significantly increasing the good HDL blood cholesterol level. Also, exercise has been shown to lower the triglyceride level, which may also be an independent risk factor for atherosclerosis and coronary heart disease.
The best way to improve your levels of total and HDL cholesterol is through a combination of exercise and diet. Do your heart a favor when you adopt the Paleo Diet and start to exercise as well.
Exercise Prevents Heart Disease and High Blood Pressure
Exercise can also decrease your risk of dying from heart disease by triggering a variety of other healthful changes in your heart and circulatory system. Regular physical exertion
has been shown to widen and increase the elasticity of the coronary arteries that carry blood to the heart. This widening is good: Even if there are plaques, or chunky deposits, in the coronary arteries of people who regularly exercise, their chances of having a heart attack are reduced because these arteries are wider—which makes it less likely that any blockage will completely cut off blood flow to the heart. With regular exercise, the heart gets bigger and stronger and may even develop new blood vessels to supply more blood and oxygen.
Also, exciting new evidence suggests that regular physical exertion may reduce the risk of a blood clot forming in a coronary artery—a key event leading to a heart attack. The net result of all these beneficial changes from physical activity is a significant reduction in your risk of dying from all forms of heart and blood vessel diseases. This has been demonstrated in a medical study of more than 40,000 women from Iowa.
The most pervasive of all chronic Western diseases is hypertension, or high blood pressure. It affects at least 50 million Americans, and by age sixty-five almost 60 percent of all Americans have blood pressure that is too high. Blood pressure is measured when the heart contracts (this is called “systolic pressure”) and when it relaxes (“diastolic pressure”). You are considered to have hypertension if your systolic blood pressure readings are 140 or greater and if your diastolic readings are 90 or greater. Many studies have demonstrated that regular exercise alone—without other lifestyle changes—is effective in lowering blood pressure. Because hypertension can accelerate the risk of stroke, exercise programs that lower blood pressure may also reduce the risk of stroke. Exercise, along with the foods you will be eating on the Paleo Diet, will put you on the right track for lowering your blood pressure and reducing your risk of developing the diseases of the heart and the blood vessels.
Exercise, Type 2 Diabetes, and Other Health Benefits of Exercise
Type 2 diabetes affects an estimated 17 million Americans and normally arises from insulin resistance—the same dangerous condition that promotes obesity, hypertension, heart disease, and blood lipid abnormalities. Exercise can be of great help: a single round of exercise improves insulin sensitivity within three hours and keeps working all day long—even twenty-four hours after your exertion.
Exercise is one of nature’s best cures for whatever ails you. Regular physical exertion can reduce stress and optimize your mental well-being, help you sleep better, improve your digestion and lung function, reduce bone mineral loss, and slow the physical changes associated with aging. It may decrease your risk of developing certain types of cancer. So go for it! Embrace the active lifestyle that is part of your ancestral heritage. Activity and movement are built into your genes. Your body absolutely requires it.
Modern Exercises for Your Paleolithic Body
Any activity is better than no activity. It doesn’t have to be some ambitious plan devised by a personal trainer. Basically, whenever you can exert yourself physically—at work, at home, while traveling, or during leisure time—you should do it. On a typical day, most Americans walk about 30 feet from the house to the car, drive to work, walk 100 feet to the office, and sit virtually motionless in front of a computer for hours at a time. At the end of the day, they walk back to their cars, drive home, and then sit motionless in front of a TV screen until they go to sleep. Even in once highly active professions, such as construction, it is now possible to do almost as little physical activity as somebody performing a desk job. Operating an air-conditioned backhoe with fully hydraulic controls takes barely more effort than operating a personal computer.
Increasing Your Activity Level While at Home or at Work
In this highly mechanized, technological world, you can increase your physical exertion level while doing your daily tasks at home or at work, during your leisure activities, and by incorporating a regular exercise routine into your schedule. I encourage you to take full advantage of all three of these situations to get activity back into your life. At every occasion when you have the chance to use your body, you should. Look upon activity not as something you have to do but rather as a fleeting opportunity to give your body a gift. Get it when you can! You’ll feel better when you do.
Is it possible for you to sneak in some exercise on the way to or from work? Could you walk to work? Ride your bicycle? How about parking your car a half mile from work—or getting off at a bus or subway stop farther away and walking the rest of the way? How about taking the stairs or walking instead of driving to lunch? Better yet, go for a walk at lunchtime and brown-bag a Paleo lunch afterward. You can even keep a portable stair-stepping device and a few small dumbbells in your office. Maybe you have access to a health club or a gym near work where you can take a quick swim, do some weight lifting, or get in a game of racquetball during your lunch hour. When you go to the restroom, take a roundabout route up and down a couple of flights of stairs. Because almost everybody notices an increase in daily energy levels (there is no mid-afternoon slump) within days of starting the Paleo Diet, you will have the energy and spirit for these extra activities. Look for physical activity—lifting, walking, climbing stairs, digging in the garden—wherever you can. Anything extra you can do is better than doing nothing, and all of these little increments add up.
At home, try not to use some of your laborsaving devices. For example, a snowblower gets the job done faster, but unless you’re going to use the time saved for exercise later in the day, shoveling the snow would be much better for you. Important note: Beware the “weekend warrior” syndrome. If you have been sedentary, don’t charge in with major aerobic exercise all at once. Talk to your doctor and figure out the safest, best way for you to get back in shape.
Increasing Your Activity Level during Leisure Time
During your leisure time, instead of watching a fishing show on TV, go fishing. Instead of watching a football game on TV, go out and throw the football around with your children. Instead of playing games on the computer, go for a walk or a hike or do some gardening. When you go to the beach, don’t just sit there; try a bit of swimming, a walk, or maybe even jog in the sand. Leisure-time activities can be enjoyable and still involve exertion. When you go shopping, make sure you do as much walking as possible. Camping trips don’t necessarily have to be junk-food feasts involving little or no physical activity. You can enjoy the great outdoors by doing something in it, such as hiking, chopping wood, or swimming. Be creative. Developing a more active life at home and at work will give you a great start in emulating the exercise patterns of our Paleolithic ancestors and will go a long way toward improving your health. Unless you do very strenuous work on the job or at home, however, you will probably need to complement your daily work and leisure activities with a structured exercise program as well.
Structured Exercise Programs
The physical activities of hunter-gatherers most closely resembled those of modern cross-training athletes, in that they were required to do both aerobic and strength activities periodically. Men commonly hunted from one to four days a week, with intervening days of rest. Hunting involved long walks and jogging (up to 10 to 15 miles) to find herd animals; dramatic sprints, jumps, and turns; occasionally violent struggles; and lengthy hikes home carrying the kill. Every two or three days, women routinely gathered; they spent many hours walking to sources of food, water, and wood. Foraging often involved strenuous digging, climbing, and then carrying heavy loads back to camp—usually with an infant or a young child on the woman’s hip or back. Other common activities, some physically taxing, included taking care of children, making tools, building shelters, butchering animals, preparing food, and visiting. Dances were a major pastime and could take place several nights a week—often lasting for hours. The overall activity pattern of these people was cyclic: days of intense physical exertion (both aerobic and resistive) alternated with days of rest and light activity.
These activity patterns suggest that most of us are best adapted to exercise programs that alternate strength and aerobic activities, a
ccompanied by intervening days of rest or low-level activities. As you develop an exercise program, you should keep these concepts in mind. Hard days should be followed by one or more easy days, and strength training (weight lifting) should accompany aerobic training. Although the bottom line is that any exercise is better than no exercise, you will be less susceptible to injury and will obtain superior overall fitness if you can follow these fundamental principles.
Aerobic Training Programs
You may already be fit and exercising regularly. Or you may do sporadic exercise. Or maybe you are overweight, and you hardly ever exercise. What you begin to do now—the amount and intensity of your exercise program—will necessarily depend on your starting point.
In order to gain the minimal health effects of exercise, you will need to accumulate at least thirty minutes of aerobic activity (walking, jogging, swimming, cycling, aerobic dance, stair climbing, racquetball, basketball, etc.) of moderate intensity on most, and preferably all, days of the week. Additional health and functional benefits of physical activity can be achieved by devoting more time to the activity, by increasing the vigor of the activity, or by increasing the number of times per week you exercise.
If you’re a beginner, you may not be able to walk for thirty minutes a day, every day, right away. Always listen to your body and increase or decrease your exercise accordingly. If you have a family history of heart disease, are very obese, or have other health problems, you should talk to your doctor or even have a checkup before you begin your exercise program. However, don’t use this as an excuse to avoid exercising. Not exercising is more hazardous to your health than exercising is. If you feel sore or tired from a day’s exercise, take the next day off, just as our hunter-gatherer ancestors would have done. Gradually, as you become more and more fit, you will be able to increase the frequency, intensity, and duration of your exercise program. Your fitness level will generally change more rapidly if you heighten the intensity of exercise, rather than increase the frequency or duration.
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