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Ever since I moved back to San Diego on February 1 I have been struggling with post-exercise recovery. For a while I was just struggling with my running in general. I've gotten past that period of malaise and am now performing reasonably well in my planned hard workouts, but I am still feeling much crappier and running much more slowly than I am accustomed to doing in the recovery runs that I complete 24 hours after each hard run. Two days ago, however, I stumbled upon an embarrasingly obvious likely explanation for the pattern.

 

 

On that day I did a hard session of 300-meter intevals on the track. I started the workout at about 4:30 pm. As soon as I finished, I drove straight home to meet up with my wife and a couple of friends and head out to a restaurant for dinner. By the time I put the first bite of appetizer in my mouth it was nearly 7:30, more than two hours after I had completed my run. This is not good, I thought. If I had a nickel for every time I have written about the importance of consuming protein, carbs and fluid within the first two hoursand ideally within the first hourafter completing a workout I could retire. Research has shown that athletes who wait too long to nourish themselves after training seriously compromise their physiological recovery processes and sabotage their performance in the next day's training. So I kicked myself for failing to drink some Endurox R4 or get some other kind of appropriate post-workout nutrition fix after leaving the track.

 

 

In the next moment I suddenly realized that I had been neglecting my recovry nutrition after every weekday run since returning to office work 10 weeks earlier. Before the move I was doing my main workout of the day at 10 or 11 am and eating lunch immediately afterward. My second workout, on days when I doubled up, took place in the evening. But since relocating I had moved my secondary workout to the early morning and pushed my main workout back to the late afternoon. My unthinking routine after these runs has been to commute back home, shower and then eat dinner. Even on a typical day when I eat dinner at home with my wife, I don't eat until 90 minutes after completing my run.

 

 

This oversight could easily explain the better part of the sluggishness I have been feeling in my recovery runs. It's not the sort of mistake a person in my position should make. I've been encouraging other endurance athletes to "drink the Kool-Aid" of post-workout nutrition for years. But where has my cup been in the past 10 weeks? Embarrassed as I am, I'm also relieved, because a solution to what had been a mystery problem until two days ago is now at hand. I'm hitting the track again this afternoon and my Endurox R4 is ready to go.

 

 

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Contrary to what many women have been led to believe, the nutritional needs of female athletes are not significantly different from those of male athletes. Research has shown that male and female athletes and non-athletes need the same 13 vitamins and 22 minerals in approximately the same amounts. Most gender-based differences in recommended daily intakes of specific vitamins and minerals can be accounted for by differences in body size, such that they are really size-based differences. The lone exception is iron, which premenopausal women need more than twice as much of due to menstrual-related iron losses. Those vitamin and mineral supplements that are "formulated especially for women/men" are nothing more than marketing gimmicks.  

 

 

The same is true for the macronutrients: carbohydrate, protein, and fat. Men and women need the same eight essential amino acids and the same essential fats. The optimal balance of macronutrients is also the same for male and female athletes: 40-70 percent carbohydrate, 15-40 percent fat, and 10-25 percent protein. The only diference is that the average man, being larger, needs more total calories each day than the average woman.  

 

 

There are gender differences in the use of nutrients in the body. For example, women burn more fat and less carbohydrate than women at moderate exercise intensities, while men burn more fat and less carbohydrate than women in the first hour or two after exercise. But these differences do not suggest the need for the two genders to eat differently.  

 

 

However, female athletes often do eat differently from male athletes in ways that prevent them from meeting some of their nutritional needs. For example, many women believe that females require more calcium than males. They do not. The reason some women believe their calcium needs are higher is that women are more likely than men to develop osteoporosis (dangerously low bone density), which is often caused in part by low bone density, and calcium is the main mineral ingredient of bone tissue. The problem of osteoporosis is so widespread that doctors and nutrition experts are constantly urging women to consume more calcium. But the calcium deficiency that sometimes contributes to osteoporosis is not due to higher calcium needs; rather, it is due to lower average calcium consumption in women.  

 

 

A lot of women avoid calcium-rich dairy foods in an effort to avoid fat. This point leads us to the core nutritional challenge that female athletes (and women in general) face as a group: social pressure to be thin. As we all know, there is in our culture a double standard that makes fuller body shapes less acceptable in women than in men. This standard motivates millions of women - and girls - to undernourish themselves in a misguided effort to look the way they think they're supposed to look.  

 

 

Athletes are as likely to be affected as non-athletes. In fact, compulsive exercise is another unhealthy way that some females attempt to achieve a warped ideal of thinness. While a great number of female athletes do develop serious eating disorders such as anorexia nervosa, much greater numbers undernourish themselves to a milder (but still unhealthy) degree. This broader phenomenon is often referred to as disordered eating. (Eating disorders are specific and severe forms of disordered eating.)  

 

 

You may have heard of a condition called the female athlete triad. The three health conditions comprising this triad are disordered eating, amenorrhea (cessation of menses), and osteoporosis. Often, but not always, these conditions are present simultaneously in female athletes who are undernourishing their bodies due to negative body image. (Two-thirds of American women report being dissatisfied with their body weight).  

 

 

Disordered eating is typically the trigger of the triad. Inadequate energy intake combined with intense training can cause a woman's body fat level to fall so low that the ovaries no longer produce adequate estrogen. This hormone is critical for normal menses and also for bone formation. Calcium deficiency, when combined with low estrogen, makes the bones even thinner and more brittle, thereby increasing the risk of stress fractures.   Here are some tips to avoid undernourishing yourself as a female athlete:  

 

  • Don't eat by your own rules. Eat by the established rules as explained in this book and other credible resources. And don't make up your own ideal body weight. Your ideal body weight is whatever body weight you end up with after consistently eating right and training well for several months. Focus on the process, not arbitrary goals that may or may not be realistic.

  • Ask yourself whether you are satisfied with your body weight. If you are not satisfied, and yet your body composition is in the healthy range, consider the possibility that the real problem is not your body weight but your body image, and talk to your doctor about it.

  • Beware of restricting certain types of foods. Many female athletes eliminate dairy from their diet or become vegetarians in order to facilitate weight loss. What they really end up doing is undernourishing themselves - eating too few calories, or not getting enough of specific nutrients that are most abundant in animal foods (e.g. protein, calcium, and iron). There is really no legitimate health reason to avoid dairy foods or meat. So unless you have an ethical or religious reason for doing so, I don't recommend it.

  • See a doctor if you miss three menses not due to pregnancy or if you suffer frequent stress fractures.

 

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Fat is the muscles' primary fuel for low- to moderate-intensity exercise. Carbohydrate is the muscles' primary fuel for moderately high- to high-intensity exercise. Carbohydrate fuel supplies are very limited in the body, such that carbohydrate fuel depletion is a major cause of fatigue during prolonged exercise at higher intensities (e.g. triathlons and marathons).  Fat fuel supplies are virtually unlimited in the body.  Thus, by increasing their reliance on fat fuel and decreasing their reliance on carbohydrate fuel during race-intensity exercise, endurance athletes could theoretically delay fatigue and perform better.  Endurance training and increased fat consumption are known to increase fat burning during exercise.  But is there solid proof that endurance athletes can actually perform better by training and eating to burn more fat?  Let's explore the question.

 

Several years ago, researchers from the University of Buffalo published an interesting study on the performance effects of various levels of fat consumption in men and women.  Endurance and VO2max tests were performed at the end of four-week periods in which runners consumed diets of 16 percent, 31 percent, and 44 percent fat.  Time to exhaustion in the endurance test was 14 percent greater at the end of the medium-fat diet than it was at the end of the low-fat diet.  However, there was no change in VO2max.

 

 

One major limitation of this study was that the order of the diets was not random, therefore we cannot rule out the possibility that the runners performed better in the second endurance test because they were more familiar with it, or in better shape, not because of their diet.  Also, there was no difference in the rate of fat burning in the second endurance test versus the first.  If higher fat intake was the cause of superior endurance, we would expect increased fat burning during exercise to be the mechanism.

 

 

Other research, however, has found that increased fat intake does result in greater fat oxidation during exercise.  Researchers from New Zealand compared the effects of a 14-day high-carbohydrate diet, a 14-day high-fat diet, and an 11.5-day high-fat diet followed by a 2.5-day carbo-loading diet on fat oxidation and performance in a 15-minute cycling test and a 100-km cycling test.  Performance in the 15-minute test was slightly better after the high-carb diet, but not to a statistically significant degree, while performance in the 100-km test was slightly better, but again not to a statistically significant degree, following the high-fat diet.  Fat oxidation was significantly greater during the 100-km test following the high-fat diet.

 

 

Like this study, other studies have also suggested that, while increased fat intake may increase endurance, it may also reduce performance in shorter higher-intensity races.  In a recent review of the existing literature, researchers from Kansas State University wrote, "We and others have observed that although fat oxidation may be increased, the ability to maintain high-intensity exercise (above the lactate threshold) seems to be compromised or at least indifferent when compared with consumption of more carbohydrate."

 

 

That's why the New Zealand researchers mentioned above thought to include a hybrid diet-a high-fat base diet followed by a short carbohydrate-loading period-in their study.  The rationale for this approach is that a couple of weeks on a high-fat diet will stimulate increases in fat oxidation capacity during exercise, and that following this adaptation period with a couple of days of carbo-loading immediately preceding a race or other maximal endurance effort will maximize muscle glycogen stores, so the athlete has the best of both worlds.

 

 

A recent study from University of Cape Town, South Africa, suggests that this strategy just might work.  Researchers examined the effects of a high-fat diet versus a habitual diet prior to carbohydrate loading on fuel metabolism and cycling time-trial performance. Five trained cyclists participated in two 14-day randomized cross-over trials during which they consumed either a 65 percent fat diet or their habitual 30 percent fat diet for 10 days, before switching to a 70 percent carbohydrate diet) for three days.

 

 

All subjects then performed a cycling test consisting of 2.5 hours at 70 percent of peak oxygen uptake followed immediately by a 20-km time trial. The high-fat diet resulted in increased total fat oxidation and reduced total carbohydrate oxidation during exercise. Most noteworthy, the high-fat treatment was also associated with improved time trial times.  On average, the cyclists completed the 20-km time trial 4.5 percent faster after the high-fat diet.

 

 

The problem with this study is that the design of the exercise test was biased to take advantage of improved fat burning.  The initial 2.5-hour ride at a moderately high intensity ensured that the cyclists' muscles were significantly glycogen depleted before they even started the time trial, forcing a greater reliance on fat, of which the cyclists were more capable after the high-fat diet.  But if this study had instead involved a time trial after a standard warm-up, it is unlikely that the high-fat diet would have been seen to result in better performance.  Indeed, other studies have found that a high-fat diet followed by a carbo-loading phase impairs performance in high-intensity time trials.

 

 

What about Training for Fat Burning?

 

 

Some endurance sports coaches believe in emphasizing training in the "fat-burning" zone (approximately 60 percent VO2max) to increase fat-burning capacity and thereby increase fat-reliance in races.  Perhaps the best-known advocate of this approach was Phil Maffetone, an endurance sports coach who made his name by developing a training philosophy that was characterized by an extreme emphasis on the importance of fat metabolism. He taught his athletes to do virtually all of their training at a very low intensity to maximize fat metabolism and stimulate physiological adaptations that increased the body's capacity for fat oxidation in subsequent workouts. Over time, Maffetone believed, the athlete would be able to swim, bike or run faster and faster at the same, low, fat-burning intensity.

 

 

Research has shown that training in the fat-burning zone does improve fat-burning capacity.  However, it only improves fat-burning capacity within the fat-burning zone itself-that is, at lower exercise intensities.  No matter how fit they are or in what manner they've trained, all runners rely on carbohydrate when racing at intensities that are near or above the lactate threshold.  Indeed, despite being well adapted for fat burning, elite male marathon runners oxidize carbohydrate almost exclusively during competition.  Only slower marathon runners (3:30-plus) and ultramarathon runners are likely to benefit from emphasizing training in their fat-burning zone.

 

 

In summary, there is probably nothing special you need to do with your diet or your training to become a fat-burning machine and, as such, a faster racer.  Proper training will automatically increase your fat-burning capacity, but this adaptation will not directly influence your performance in races lasting less than several hours.  If you care to, you may experiment with 10 or 11 days on a high-fat diet followed by two days of carbo-loading before a longer race, as it won't harm you and there's a slight chance it might help.

 

 

 

 

 

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