The Paleo Diet for Athletes (17 page)

Accelerated glutamine loss from a net acid-producing diet may adversely affect exercise performance through a wide variety of mechanisms. Glutamine supplementation has been shown to increase growth hormone and help spare muscle mass in critically ill patients and in some animal experiments. Also, like alanine, glutamine can be converted to glucose in the liver and may provide an additional carbohydrate source during prolonged exercise. Finally, depleted blood glutamine levels in endurance athletes are a symptom of overtraining and increase the likelihood of infection and upper respiratory illness. Because most endurance athletes eat a net acid-producing diet similar to the typical American diet outlined in
Table 5.4
, chances are good that glutamine reserves will be compromised. By following the Paleo Diet for Athletes, you will be getting plenty of glutamine from fresh meats, fish, and seafood.

TABLE 5.4

Acid/Base Balance in Average US Diet

Net Acid-yielding Foods

Cereal grains = 23.9% energy

Meats, fish = 15.7% energy

Dairy = 10.6% energy

Nuts, legumes = 3.1% energy

Eggs = 1.4% energy

Salt = 9.6 g/day

Net Alkaline-yielding Foods

Vegetables = 4.8% energy

Fruits = 3.3% energy

Neutral (But Displace Alkaline Foods)

Refined sugars = 18.6% energy

Refined oils = 17.9% energy

Values represent percentage of the total daily energy consumed.

FIBER INTAKE

The average person in the United States does not get enough fiber. Current intakes (15 grams per day) fall way short of recommended levels (about 25 to 35 grams per day). When you adopt the Paleo Diet for Athletes, fiber will become a nonissue because you will get it almost entirely from fresh fruits and vegetables. A common perception is that whole grains are excellent sources of fiber. Think again.
Figure 5.7
shows this not to be the case in its depiction of the average total fiber content in a 1,000-calorie serving of 3 refined cereals, 8 whole grain cereals, 20 fresh fruits, and 20 nonstarchy vegetables. When it comes to soluble fiber, whole grains are lightweights compared with fruits and veggies.

Fiber has little influence upon exercise performance, but it helps to normalize bowel function and prevent constipation, and it may help to avert “runner’s trots,” which can be more embarrassing than detrimental to performance. Increased fiber consumption may also slightly improve your blood chemistry and over the course of a lifetime may prevent varicose veins, hemorrhoids, hiatal hernia, and other illnesses associated with the gastrointestinal tract.

FIGURE 5.7

TRACE NUTRIENT DENSITY

In
Chapter 1
we showed you what a nutritional lightweight the USDA Food Pyramid/MyPlate diet is compared to the Paleo Diet for Athletes, particularly when we get down to the issue of vitamins and minerals. Most people in the United States would be lucky to eat as well as the USDA Food Pyramid/MyPlate designers would like us to eat. In fact, we don’t do very well at all.
Table 5.5
shows that more than half of the US population gets insufficient vitamin B
₆
, vitamin A, magnesium, calcium, and zinc. The problem comes not only from our avoidance of fruits and veggies but also our consumption of so many empty calories in the form of refined sugars and grains in processed foods. Refined sugars make up 18 percent of our daily calories yet have absolutely zero vitamins and minerals. Grains compose 24 percent of our daily food intake, but, unfortunately, 85 percent of the grains consumed in the United States are taken as refined grains.
Figures 5.8
and
5.9
show how the refining process strips whole wheat of most of its vitamins and minerals.

TABLE 5.5

US Individuals Age 2 and Older Meeting RDAs

These are the 13 nutrients most lacking in the US diet (1994-96), according to 1989 RDAs.

FIGURE 5.8

FIGURE 5.9

These figures give you a pretty good idea that white flour is a nutrient-depleted mess! Even governmental agencies understand that white flour isn’t such a good thing. Starting shortly after World War II, all white flour was required by law to be enriched with vitamins B
₁
, B
₂
, B
₃
, and iron. It’s almost inconceivable to call this stuff “enriched” when at least 18 vitamins and minerals are severely depleted during the refining process, yet only 4 are added back. Wait, make that 5. In 1998, legislation by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) mandated further supplementation of white flour with folic acid.

Folic acid is an artificial compound first synthesized by scientists at Lederle Labs in 1947. After ingestion, it is converted into the B vitamin folate by the liver. Note that folic acid and folate are not one and the same compound. Rather, folic acid is metabolized in a slightly different manner in the body than the naturally occurring B vitamin folate. Leading up to the 1998 federal legislation mandating folic acid supplementation, an increasing body of scientific literature had suggested that folate deficiencies were responsible for the crippling and often fatal birth
defects known as neural tube defects. Accordingly, the governmental rationale for folic acid fortification in the US food supply was to reduce the incidence of neural tube defects, of which spina bifida is most well known.

In a 6-year period (1990-1996) before mandatory folic acid fortification, the average number of neural tube defects per year in the United States was 1,582. In the first year (1998-1999) following fortification, neural tube defects dropped to 1,337, so 245 cases of this disease were prevented. The problem with population-wide folic acid supplementation was that it had never been adequately tested in large randomized, controlled human trials to determine if this artificial compound had any adverse health effects. I would be the first person to congratulate governmental agencies for mandating a national policy that could reduce or eliminate neural tube defects. Unfortunately, this shotgun approach put the entire US population (300 million people) at risk for death and disability from other more serious diseases.

In the last decade, an accumulating body of scientific evidence now makes it clear that the FDA’s mandatory folic acid fortification program represents a terrible blunder in US public health policy. An alarming number of human clinical trials, animal experiments, and epidemiological studies show that excess folate via folic acid fortification has resulted in population-wide increases in the risk for breast, prostate, and colorectal cancers. Although scientists aren’t completely sure how excess folate and folic acid promote cancer, animal experiments indicate that these compounds induce a cancer-causing reaction called hypermethylation in the DNA of cancer cells.

Because the Paleo Diet for Athletes recommends that you should severely restrict or eliminate all grains, the nationwide folic acid fortification program becomes a nonissue for Paleo Dieters, providing you do not take folic acid-containing vitamins or supplements. As we have made it clear throughout this revision, supplementation (except for fish oil and vitamin D) is unnecessary, and antioxidant supplements may actually prevent the health promoting effects of exercise and hamper training adaptations in endurance performance.

It would appear that you are a whole lot better off eating whole grains to get calcium, iron, magnesium, and zinc. Wrong! Whole grains contain numerous substances called antinutrients that can impair nutrient absorption or adversely affect health in a wide variety of ways. Phytic acid, otherwise known as phytate, is an antinutrient found in all whole grains and legumes that binds calcium, iron, magnesium, and zinc and severely inhibits their absorption. Whether whole or refined, grains are an inferior food when it comes to vitamins and minerals. Do yourself a favor and get the bulk of your carbs from fresh fruits and veggies.

CHAPTER 6

F
ITNESS AND
F
OOD

There are three factors that contribute to fitness. The first, and most important, is a sound training program that focuses on the demands of high performance. Without physical stress as created by challenging workouts, your body will not have the stimulus to adapt and grow stronger. The second contributor to performance is rest, especially adequate sleep. It’s during sleep that your body experiences the process of adaptation. Workouts provide the potential for fitness, but it’s realized while you are resting and sleeping. During rest and sleep your body requires resources to rebuild. These are the macronutrients (protein, fat, and carbohydrate) and the micronutrients (vitamins and minerals). This is the third factor in fitness. These dietary contributors make growth and adaptation to the stress of training possible. If these nutrients are not adequate in your diet, then not only will your athletic performance suffer, but also your health. There are several other ways that your diet affects fitness. We will examine them here. Let’s start with the most basic question.