As
previously mentioned, I've been studying Matt Fitzgerald's book,
New Rules of Marathon and Half Marathon Nutrition, and implementing his methods throughout my own training in combination with the Runners Connect Marathon Nutrition Blueprint. The philosophies are generally in alignment, with the Blueprint more specific for race day fueling strategy and
New Rules informing most of my general training nutrition approach.
With the Tomoka Marathon nine days away, I am now five days into my marathon taper! During past marathons, I had not taken my taper nutrition as seriously as I should have. Sure, added in more carbs in the three or four days before the race, but no other real strategy or method there. How I did in those races varied somewhat, but even in my most successful, BQ-ing race, I hit the wall, every time. This time I am dedicated to pushing that wall away, and feel very confident in my ability to properly fuel during the race thanks to Runners Connect's Blueprint. As for the taper diet, I am now on Day 5 of Fitzgerald's recommended approach: 65% of calories from fat for 10 days (on a 2-week taper), then switching to 70% of calories from carbohydrates for 3 days prior to competition.
The idea is that by cutting carbs and cuing fat, the body switches into a zone of higher fat utilization as primary fuel, priming the athlete's system to burn fat more effectively before switching over to carbs. Marathon runners would sustain their activity for a longer period of time before becoming glycogen depleted, aka "hitting the wall." The 3-day carb loading period ensures that the runner is then fully glycogen loaded before their race. In essence, it provides the best of both worlds: capacity to burn mostly fat, but also turbo-loaded with carbs.
The approach is also grounded in some practice, namely one particular study, described
here on Competitor.com:
"In 2001, Vicki Labert, and exercise scientist at the University of Cape Town, South Africa, tested the effects of 10 days of fat loading followed by three days of carbo loading on endurance performance in cyclists. After warming up with two hours of moderate-intensity cycling, Lambert's subjects were able to complete a 20K time trial 4.5 percent faster after using this protocol than they did when carb loading was preceded by their normal diet." - Matt Fitzgerald, Competitor.com, Nov 22 2013
My understanding of the human body's adaptability to metabolic changes such as these leads me to believe that a runner on a high fat / low carb diet would have to be doing so for quite some time during training to stimulate such an adaptation, not just for 10 days prior to competition. But Fitzgerald's nutritional approach already somewhat addresses this, with "fasting workouts" during training. As I described in a
previous post, this method involves fasting for all shorter, slower runs, about half of all moderate intensity / moderate distance runs, and fueling with carbohydrates for all high-intensity workouts and all runs lasting longer than 2 hours. This ensures that your body is able to perform at its best during key training runs, yet also allows your body to adapt to a low-glycogen scenario, forcing it to burn fat as the primary source. Again, the best of both worlds.
So if you have already trained with "fasting workouts" consistently during training, your metabolism is already somewhat primed to use fuel efficiently during the marathon. This 10-day fat-loading time provides that extra push at the end of training....and you still get the carbs for the last 3 days, to top off your glycogen stores.
Incidentally, due to a cut back in mileage, Fitzgerald and Runners Connect both remind runners to cut calories somewhat during taper. This is common sense: running less + eating the same amount of calories as when you're high-mileage training = possible weight gain just before your race. At the same time, you definitely don't want to under-eat during taper period either. To figure out how many calories to cut from your daily intake, Fitzgerald recommends multiplying [your weight] x [the number of miles per day LESS than you normally run] x [0.63]. So for, say a 135 lb runner who usually runs 8 miles in a day, but during taper runs 4 miles:
135 x 4 x 0.63 = 340 calories to subtract from your daily intake.
**Important note: Do NOT worry that switching to fat will cause you to gain weight. Assuming your total calorie intake is appropriate to your activity level, you should not gain weight aside from a couple pounds of water weight when you carbo load (which is to be expected). Dietary fats do not automatically equate to storing body fat. In fact, pretty much all research now shows that sugar is the weight-gain culprit, not fat.**
Competitor.com gave a great
summary of Fitzgerald's nutrition method. Check it out of you like what you've read here and want to implement these strategies into your training and racing.
Now for my experience.
Again, I am on Day 5/10 of fat loading. This has been a major adjustment for me, not only as a runner, but also as a breastfeeding mother. I have actually been hitting about 55-60% fats, not the full 65%, most days (I am trying to maintain a SLIGHTLY more balanced ratio for the sake of lactating, and because I have actually been slowly losing weight over the last couple of months.) Getting 65% of your calories from fat is HARD WORK, let me tell you, especially if you are typically a carb hound like me. It means two pieces of bread and a mandarin orange, and BOOM, you've had all the carbs you can have for the day (assuming you're consuming around 2500 calories / day) and need to fill up on nuts, cheese, olive oil, salmon, whole milk, cheese, peanut butter, eggs, cheese, and cheese. If you crave these foods, then you will be one happy camper for 10 days. I, however, have not been, but am just now kind of getting used to it.
One drawback - you will feel fatigued and weak on your runs during fat-loading. DO NOT DESPAIR! I know it is a bit of a mind-warp what with everything else you feel and think during tapering. It is discouraging to feel slow, heavy, and weak, when you already might be a paranoid nervous wreck during taper. But fear not - as soon as you switch over to carbs, you will feel like a hypercharged rocket booster, and might bounce off some walls. That will be a good feeling to have just before your race.
I will touch base again after a couple of days of carbo loading and just before my race, if I will have the capacity to sit down long enough to blog whilst turning into a carbo-surging superhuman beast.
So far, I am confident in this approach and am building excitement for my race! Also, a BIG thanks to the staff at
Runners Connect for their help and support during my training. Excellent advice, a caring team, an awesome podcast, and the Marathon Blueprint is a fantastic tool. I will be writing about how that has worked out after my race.
