The Paleo Diet for Athletes (19 page)

The fat burner will start the test with an RER of around 0.80, meaning that he or she is already using about 33 percent carbohydrate and 67 percent fat for fuel (see
Table 6.1
). That’s good. An otherwise similarly fit sugar burner, in terms of aerobic capacity, may start the test at the same low intensity but with an RER of perhaps 0.90 or higher. At this RER he or she is burning 67 percent carbs and 33 percent fat. That’s not so good. When they reach their anaerobic thresholds, both the fat burner and sugar burner will be at about 1.00 RER, which means 100 percent carbohydrate and zero percent fat. (Fatigue will typically end the test at an RER of about 1.1 to 1.2 for both.)

Notice that the sugar burner has a much narrower RER range (0.90-1.00) than has the fat burner (0.80-1.00). So at moderate intensities, as are common in long-distance events, the sugar burner needs to be very aware of carbohydrate intake as he or she risks running low on this precious fuel. If that happens, the athlete bonks. Some athletes are such gigantic sugar burners that they find it difficult to take in enough carbohydrate during the competition. They must go slow to lower their use of stored glycogen. They’re using sugar faster than their stomachs can process it from sports drinks. That often means a gut “shutdown” and nausea.

If you discover from a test that you are a sugar burner, you may be able to modify this condition somewhat. I say “may” because there is some research indicating that there is an element of genetics involved. This probably has to do at least in part with your muscle makeup, especially your percentage of slow-twitch or “endurance” muscles. This factor, for the most part, is an inherited trait over which you have no control. But there is also no way of knowing if your high RER is genetic or the result of something else, such as how you train.

Doing workouts that focus heavily on anaerobic effort trains the body to preferentially use sugar for fuel. Long-duration, low- to moderate-intensity aerobic workouts promote fat burning. As you become more aerobically fit, your RER will drop, and, related to that, research has shown that as training volume increases, RER is also reduced.

The other chief determinant of RER is your usual diet. Simply put, the more high glycemic load carbohydrate foods you eat (starches are the most prevalent in this category), the more your body will rely on sugar during exercise. Conversely, the more fat and protein in your diet, the lower your RER will be. Eating starch or taking in glucose in a sports drink before the start of the metabolic test, workout, or the race may also slightly shift your RER to the sugar-burning side. (This is why we recommended in
Chapter 2
not consuming anything other than water in the last 2 hours prior to starting exercise, with the exception of the last 10 minutes prior to exercise.)

It is even possible to determine how much carb you need to take in during a race from an RER test. All you need to do is find your goal race intensity—heart rate, power, or pace—for your event in the test’s raw data results and determine, also from the results, how many calories you were burning at that point. Then check RER at that same intensity (see
Table 6.1
) to see what percentage of those calories came from sugar. You will need to replace much of this expended, carb-based energy during long events (see
Chapter 3
for details). The test technician can help you figure this out.

Knowing your RER and, more important, keeping it on the low side through diet and training have the potential to improve your performance in long-distance endurance events.

Lowering your RER so that you are more economical is a good starting point for using food to improve your fitness. But there is much more to be gained from what you eat and when you eat it. As discussed in
Chapters 2
,
3
, and
4
, this is something that changes throughout the day. But there are also dietary shifts going on throughout the season that have a strong influence on fitness and race performance.

PERIODIZATION OF DIET

In working with athletes from novices to elites, we have found that varying the Stage V diet along with training volume and intensity produces
the best performances. By varying the macronutrient intake, it is possible to enhance the benefits sought in different types of training at certain points in the season. For example, if a purpose of the base (general preparation) period is to train the athlete’s body to preferentially use fat for fuel, thus sparing carbohydrate, and we know that eating a diet higher in fat and lower in carbohydrate also promotes such a metabolic shift, then it seems reasonable to have the athlete eat more fat and less carbohydrate at this time in the season. We have used this strategy with athletes and observed changes in RER as described above indicating that glycogen, the muscles’ storage form of carbohydrate, was being spared, compared with pretests in which carbohydrate was relatively high and fat low in the diet. There is a growing body of research in this area that supports the notion that aerobic training, along with a greater intake of fat, produces increased benefits in the form of glycogen sparing.

In the same way, when the intensity of training increases to become more race-like while volume stabilizes or perhaps decreases slightly in the build (specific preparation) period, the athlete uses more carbohydrate for fuel. During this period, which occurs about 6 to 12 weeks before priority A races, it is wise to increase the carbohydrate content of the diet slightly, while decreasing fat intake. This means being particularly focused on carb intake in Stages III and IV following workouts and eating plenty of fruits and vegetables in Stage V. Protein stays stable relative to the total training workload throughout the season.

Before going into more detail on this subject, it is important that we explain some basic tenets of periodization. Periodization is a system in which the athlete’s training program is modified over time so that a high level of fitness is typically achieved two or three times in a season. This system of training, largely developed by Eastern bloc countries in the 1960s, has been prevalent in Western countries since the 1970s and is widely employed by serious athletes around the world. In periodization, the season is divided into periods that may be 1 to 12 weeks in duration; each has a purpose and a unique method of training associated with it.

In the classic periodization model, the training year begins with general preparation made up of the “preparation” and “base” periods. The purpose of training for endurance athletes at this time is to produce gains
in the areas of general aerobic endurance, muscular strength, and sport skills. The training at this time in the season is not specific to the intensity and duration demands of the targeted event, but rather general in nature.

Following this is specific preparation for competition during the “build” and “peak” periods when training becomes increasingly specific to the demands of the coming event. This is usually marked by a shift in emphasis from general endurance to higher-intensity training, although this is determined by the targeted race’s characteristics. For example, for very long events, workout intensity is relatively low, and moderate-intensity endurance training continues much as in general preparation—although there may be race-specific training adjustments made relative to terrain, weather conditions, and equipment used. In the 1- to 2-week peak period just prior to the competition, it is common for the athlete to significantly reduce the training volume while completing a “dress rehearsal” workout every 2 or 3 days. During these periods, the gains made in the general preparation period are maintained, with reduced frequency of training for endurance, strength, and skills.

Next comes the competition or “race” period. This is what you’ve trained for. It’s when the all-important priority A races are scheduled. For most athletes, the race period is best kept quite short—no more than 1 week. A few athletes—most likely elites, who have greater capacity when it comes to devoting themselves to extensive training and limited recovery—may be able to hold a peak of fitness for a few weeks. Attempting to maintain a peak level for too long will result in a gradual erosion of fitness due to the emphasis on rest.

The race period is followed by the “transition” period, when physical and mental rejuvenation is the goal. This may last from a few days at midseason to a few weeks at the end of the race season.

Just as the duration, frequency, and intensity of training are adjusted throughout the season, so must the types of foods and when they are eaten, as well the amount of calories consumed.
Table 6.2
summarizes these objectives and unique nutritional requirements. When the workload is the greatest, in the base and build periods, the volume of food eaten and subsequent calories consumed are also at the highest levels for
the year. With these as the standard, or 100 percent level, the other periods will require fewer calories since the recovery demands are not as great. As previously explained, there should be a shift between carbohydrate and fat according to the demands of the training sessions and races. Protein remains about the same throughout the year.
Table 6.3
demonstrates these caloric and macronutrient adjustments.

TABLE 6.2

The Parallel Purposes of Training and Nutrition While Following a Classic Periodization Model

TABLE 6.3

An Example of Caloric Breakdown by Training Period