The Paleo Diet Read Online Free PDF Page B

disease, cancer, and osteoporosis. Yet just one papaya (59 grams of carbohydrate) would blow the daily limit for two of the most popular low-carbohydrate diets. Eating an orange, an apple, and a cup of broccoli and carrots (73 grams of carbohydrate) —just a drop in the bucket to hunter-gatherers, whose diets were rich in fruits and vegetables—would wreck all but the most liberal low-carbohydrate diets.
    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.

The Osteoporosis Connection
    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