The Paleo Diet (5 page)

Humanity’s original carbohydrate sources—the foods we survived on for millions of years—didn’t come from starchy grains and potatoes, which have high glycemic indices that can rapidly cause blood sugar to spike. Instead, they came from wild fruits and vegetables with low glycemic indices that produced minimal,
gradual
rises in blood sugar. These are the carbohydrates that you’ll be eating on the Paleo Diet. These nonstarchy carbohydrates normalize your blood glucose and insulin levels, promote weight loss, and make you feel energized all day long.

One of the greatest—and least recognized—benefits of fruits and vegetables is their ability to slow or prevent the loss of bone density, called “osteoporosis,” that so often comes with aging. As far back as 1999, Dr. Katherine Tucker and colleagues at Tufts University examined the bone mineral status of a large group of elderly men and women. These scientists found that the people who ate the most fruits and vegetables had the greatest bone mineral densities and the strongest bones. In the ensuing ten years, more than 100 scientific studies have confirmed this concept.

But what about calcium? Surely, eating a lot of cheese can help prevent osteoporosis? The answer is a bit more complicated. One of the great ironies of the low-carbohydrate, high-fat diets is that even though they allow unlimited consumption of high-calcium cheeses, they almost certainly will be found to promote bone loss and osteoporosis in the long run. How can this be? Because getting a lot of dietary calcium from cheese, by itself, isn’t enough to offset the lack of fruits and vegetables.

Nutrition scientists use the term “calcium balance” to describe this process. It’s the difference between how much calcium you take in and how much you excrete. Most of us have gotten the message about consuming calcium. But the other part of the equation—
how much calcium you excrete
—is just as important. It is quite possible for you to be in calcium balance on a low calcium intake if your calcium excretion is also low. On the other hand, it’s easy for you to fall out of calcium balance—even if you load up on cheese at every meal—if you lose more calcium than you take in.

The main factor that determines calcium loss is yet another kind of balance—the
acid-base balance.
If your diet has high levels of acid, you’ll lose more calcium in your urine; if you eat more alkaline foods, you’ll retain more calcium. A study in the
New England Journal of Medicine
by my colleague Dr. Anthony Sebastian and his research group at the University of California at San Francisco showed that simply taking potassium bicarbonate (an alkaline base) neutralized the body’s internal acid production, reduced urinary calcium losses, and increased the rate of bone formation. In a follow-up report in the
New England Journal of Medicine,
Dr. Lawrence Appel at Johns Hopkins University reported that diets rich in fruits and vegetables (these are alkaline foods) significantly reduced urinary calcium loss in 459 men and women.

See Appendix A for a list of common foods and their acid-base values.

Cereals, most dairy products, legumes, meat, fish, salty processed foods, and eggs produce net acid loads in the body. By far the worst offenders on this list are the hard cheeses, which are rich sources of calcium. Again, unless you get enough fruits and vegetables, eating these acid-rich foods will actually promote bone loss and osteoporosis.

Virtually all fruits and vegetables produce alkaline loads in the body. When you adopt the Paleo Diet, you won’t have to worry about excessive dietary acid causing bone loss—because you’ll be getting 35 percent or more of your daily calories as healthful alkaline fruits and vegetables that will neutralize the dietary acid you get when you eat meat and seafood.

Most low-carbohydrate, high-fat diets don’t address the dangers of salt; some even encourage its use. And yet there is a ton of medical evidence linking salt to high blood pressure, stroke, osteoporosis, kidney stones, asthma, and even certain forms of cancer. Salt is also implicated as a factor in insomnia, air and motion sickness, Ménière’s syndrome (an agonizing ear ringing), and the preeclampsia of pregnancy.

Salt is made up of sodium and chloride. Although most people think that the sodium portion of salt is entirely responsible for most of its unhealthful effects, chloride is just as guilty, if not more so. The average American eats about 10 grams of salt a day (this turns out to be about 4 grams of sodium and 6 grams of chloride). Chloride, like cereals, dairy products, legumes, and meats, yields a net acid load to the kidneys after it is digested. Because of its high chloride content, salt is one of the worst offenders in making your diet more acid.

Paleolithic people hardly ever used salt and never ate anything like today’s salty cheeses, processed meats, and canned fish advocated by most of the low-carbohydrate weight-loss diets. Do your body a favor and throw out your saltshaker along with all the highly salted, processed, packaged, and canned foods in your pantry.

It’s taken half a century, but scientists have finally realized that when they stigmatized red meat, they threw out the proverbial baby with the bathwater. Meat is a mixture of fat and protein. Lean meat—such as that found in wild game and seafood—is about 80 percent protein and about 20 percent fat. But fatty processed meats like bacon and hot dogs can pack a whopping 75 percent of their calories as fat and only 25 percent or less as protein. What should have been obvious—that it was the high level of a certain saturated fat, palmitic acid, not the protein, that caused health problems—was essentially ignored. Meat protein had unfairly become a villain.

Here again, there’s a major lesson to be learned from looking at the distant past: for more than 2 million years, our ancestors had a diet rich in lean protein and healthful fats. It gave them energy and, combined with fruits and vegetables, helped them stay healthy.

When scientists actually studied how lean protein influences health, well-being, and body-weight regulation—and this has occurred only in the last two decades—they found that our ancestors were right all along. It turns out that
lean protein is perhaps our most powerful ally in the battle of the bulge.
It has twice the “thermic effect” of either fats or carbohydrates, which means it revs up your metabolism. In other words, protein’s thermic effect increases our metabolism and causes us to burn more calories than if we ate an equal caloric serving of either fat or carbohydrate. Also, more than fats, more than carbohydrates, protein has the highest “satiating value”—that is, it does the best job of making us feel full.

The principles I have laid out in the Paleo Diet—all based on decades of scientific research and proved over millions of years by our ancestors—will make your metabolism soar, your appetite shrink, and extra pounds begin to melt away as you include more and more lean protein in your meals.

But this diet gives you much more than a slimmer figure. Unlike other low-carbohydrate diets, it’s good for your heart. High-protein diets have been shown by Dr. Bernard Wolfe at the University of Western Ontario in Canada to be more effective than low-fat, high-carbohydrate diets in lowering total and bad LDL cholesterol and triglycerides while simultaneously increasing the good HDL cholesterol. My colleague Neil Mann at the Royal Melbourne Institute of Technology in Melbourne, Australia, has demonstrated that people who eat a lot of lean meat have lower blood levels of homocysteine (a toxic substance in the blood that damages the arteries and predisposes them to atherosclerosis) than do vegan vegetarians. The net result is that high-protein diets produce beneficial changes in your blood chemistry that, in turn, reduce your overall risk of heart disease.

High-protein diets have been shown to improve insulin metabolism, help lower blood pressure, and reduce the risk of stroke. They have even prolonged survival in women with breast cancer.

Some people have been told that high-protein diets damage the kidneys. They don’t. Scientists at the Royal Veterinary and Agricultural University in Copenhagen effectively put this myth to rest. Dr. Arne Astrup and colleagues put sixty-five overweight people on a high-protein diet for six months and found that their kidneys easily adapted to increased protein levels. Furthermore, kidney function remained perfect at the end of the experiment.

Isn’t it time you got protein on your side? Eating lean meat and fish at every meal, just as your Paleolithic ancestors did, could be the healthiest decision you ever made.

Compared to the faddish low-carbohydrate weight-loss diets, the Paleo Diet includes all the nutritional elements needed to encourage weight loss while promoting health and well-being. The Paleo Diet is designed to imitate the healthful diets of our preagricultural ancestors. It contains the proper balance of plant and animal foods—and the correct ratios of protein, fat, and carbohydrate required for weight loss and excellent health.

So, don’t be fooled by the low-carbohydrate fad diets. The Paleo Diet gives you the same weight-loss benefits, but it’s also a delicious, healthy diet you can maintain for a lifetime.

With the Paleo Diet, you’ll be restoring the diet you are genetically programmed to eat. You’ll be following the diet that every single person on the planet ate only 333 generations ago. It is the diet the modern world has completely forgotten.

The Paleo Diet is simplicity itself. Here are the ground rules:

The Paleo Diet is not a fat-free diet, it’s a “bad fat”-free diet. It has few of the artery-clogging fats found in the typical Western diet, but there is plenty of low-fat protein and good fats—such as those found in salmon and other cold-water fish, as well as in nuts and olive oil. It is not a fanatically strict diet, either.

There are three levels of adherence that make it easy to follow the diet’s principles. Each level contains a limited number of Open Meals—in which you can still eat your favorite foods. If you enjoy an occasional glass of wine or beer, that’s fine—it’s allowed here. Because the Paleo Diet is a lifetime program of eating—and not a quick-fix weight-loss diet—it has built-in flexibility to accommodate a little cheating and your own individuality.

Try it, and from the beginning your appetite will be reduced and your metabolism will be increased. This means you’ll lose weight without the hunger pangs that accompany so many diets—and ultimately doom these diets to fail. There’s no need to count carbohydrate grams in this diet. You can eat as much carbohydrate as you want, as long as it’s the good kind—the kind that comes from low-glycemic fruits and vegetables. There is no need to count calories. This is how our diet was meant to be: Eat until you’re full. Enjoy nature’s bounty. Lose weight, and be healthy while you’re doing it.

Here’s how the Paleo Diet compares to the faddish low-carbohydrate diets we discussed in the previous chapter.

The Paleo Diet is based on the bedrock of Stone Age diets:

From the work my research team and I have done in analyzing the daily food intake of hunter-gatherer societies, we have found the ideal dietary ratio. Although you don’t need to count calories with the Paleo Diet, if you did you’d find that a little more than half—55 percent—of your calories comes from lean meats, organ meats, fish, and seafood. The balance comes from fresh fruits and vegetables, some nuts, and healthful oils.

My research team and I have spent years analyzing what Paleolithic humans ate—running hundreds of computerized analyses exploring every conceivable dietary component, varying the amounts and types of plant and animal foods that were available to our ancient ancestors. No matter how we mixed up the ingredients, seven dietary characteristics consistently emerged. They are the Seven Keys of the Paleo Diet—your guidelines to weight loss and good health.

1. Eat a relatively high amount of animal protein compared to that in the typical American diet.

2. Eat fewer carbohydrates than most modern diets recommend, but eat lots of good carbohydrates—from fruits and vegetables, not from grains, starchy tubers, and refined sugars.

3. Eat a large amount of fiber from nonstarchy fruits and vegetables.

4. Eat a moderate amount of fat, with more good (monounsaturated and polyunsaturated) fats than bad (trans and certain saturated) fats, and nearly equal amounts of omega 3 and omega 6 fats.