Tapering and Fueling for the Marathon – Why both are crucial to your race day success!

With many upcoming spring marathons around the corner, many of us are starting to put the final touches on a long fall/winter training cycle. Here in the 757, everyone is gearing up for the annual Shamrock Sportsfest.

As coach of The Endurance Project http://www.meetup.com/The-Endurance-Project/ I have over 20 runners who will be participating in the marathon this year, several of which are first timers. With the recent bout of snow we have had here, many of them are freaking out more about missing a couple of training days, rather than to worry about some even bigger concerns, TAPERING, NUTRITION and RACE DAY FUELING!!! All 3 of these topics are something that can bring the best trained runner to a slow and painful death march, if ignored or improperly executed.

So, lets take a look at all 3 of the above mentioned topics, in greater detail. Within these topics, I will provide some links and insight into scientific research but, will also provide samples of my own experiences and those I coach.

TAPERING – The word “taper” is basically a 4-letter curse word in the eyes of most runners. Just the thought of tapering brings bad thoughts into the runners mind. The typical runner, rather than think about all the GOOD things that that tapering is doing, they think of all the BAD. “Oh my God, I am going to get fat”, “I am going to lose fitness and I’ll suck on race day”, “I am going to go insane without working out/running”. These are just a few things that you will hear being said by the typical runner, as they enter into those last couple of weeks leading up to their race.

So what is TAPERING, exactly? Well, in the simplest of definitions, it’s the time spent at the end of a hard training cycle, that allows the body to recover and return to homeostasis, just prior to the day of the big race.

There are many, many, many varying views on how to taper, how long to taper, what to do or what not to do, etc.

With my personal experiences, as well as those I coach, I have found that a 20 day gradual taper has been the most effective. So how does this 20 day taper work?

Essentially, starting immediately after the last tough long run (3 weeks prior to the race), the runner begins to cut back on volume and intensity, but not frequency. In layman’s terms, this means that the runner will continue running the same number of workouts per week but, will cut back on the duration of each workout, as well as cut back on the intensity of SOME of the workouts.

So why this approach? Well, the body becomes very good at adapting to stresses and repetitive actions. Because of this, running/training becomes somewhat of an addiction. The body has adapted and become accustomed to the daily, weekly routine that you have been administering over the past several months of your training phases.

So, if you spent the past 24 weeks running 5 days per week, then continue doing so right on up to the race. The frequency of your running is not so much what you need to recover and regenerate from. It’s the intensity and duration that the body needs to start tapering from.

From 3 weeks out, I like to cut weekly mileage/duration by 20%. Then cutting an additional 20% from the 2nd week out from race day. Finally, cutting back another 20% the week of the race itself. Broken down, it would look like this.

A runner who had been averaging 40 miles per week coming into the taper phase would go from 40 miles, down to 32 miles, down to 25 miles and finally, would be down to 20 miles the week of the race (totally 46.2 miles when accounting for the race itself).

Now, the taper phase has several purposes, rather than just to allow the body a bit of time to repair itself from all the pounding you have been doing over the past several months. During this time, the body also needs to begin re-supplying its glycogen stores, as well as to start getting it’s pH levels back in order. Both of these areas will be discussed further as we discuss NUTRITION.

NUTRITION – When we talk about nutrition and running, most runners only give thought to two things, the carb loading dinner the night before and the buffet of race day gels and sports drinks. Very few think much further ahead of that.

Glycogen is a competitive runners best friend (especially on race day). What is this glycogen you speak of?

“In humans, glycogen is made and stored primarily in the cells of the liver and the muscles, and functions as the secondary long-term energy storage (with the primary energy stores being fats held in adipose tissues). Muscle glycogen is converted into glucose by muscle cells and liver glycogen converts to glucose for use throughout the body including the central nervous system”

Simply speaking, glycogen is the preferred and quickest form of fuel when it comes to moving your body 26.2 miles at a relatively quick pace. Granted, the body can be taught and “tricked” into burning fat at higher ratios, however, when the body is riding the line of aerobic/anaerobic, it prefers the glycogen over fat.

The problem is, the body can only store so much glycogen at any given time. Majority of it is stored in the liver and muscles. The liver CAN process and make accessible it’s glycogen stores to other organs within the body. On the flip side, the muscles CAN’T. Meaning, that the limited amount of glycogen in the muscle is a one time deal. If you run out of glycogen in your hard working quad or hamstring, those muscles can’t pull glycogen from your less active deltoid muscle. When it is gone, it’s gone!

This is where the word “bonking” comes into play. We’ve all seen what happens when a runner “hits the wall”, many of us having experienced it ourselves. When we BONK, one of two (or both) things are happening. The body is designed to survive and, will do whatever it has to in order to do so. So, when the liver is running low on glycogen, it will send the remaining stores of it to the “important” parts of the body (brain, heart, lungs, etc….you know, the ESSENTIAL components of the machine). The body doesn’t really care about your hamstring and whether or not you get your PR in the race. During this bonk moment, the body only knows that something bad is happening and it’s up to the liver to start distributing that glycogen where it deems is most important. Your muscles not being on the “essential personnel” list.

To avoid this from happening in a race and in order to preserve your very precious glycogen stores, you must 1.) Have  those glycogen stores topped off and at their highest concentrations. 2.) You will need to ingest additional forms of glucose (or other sugar) throughout the race, so that it can preserve the expenditure of your stored glycogen.

So how do you get those glycogen stores topped off? You start several days out from the race! Part of the reason for tapering is so that your muscles can start refueling and replenishing the glycogen within your body. During your training cycle leading up to the race, your body is typically always in some form of glycogen deficiency. Because most runners train on a daily basis, their glycogen stores are never at a 100%. During the tapering phase, the body can gradually start fueling up the glycogen tanks, so that on race day, they are their max capacity.

Starting from about 10 days out, begin consuming high carbohydrate foods. Ideal foods would be wholesome/clean types, such as fresh fruit and juices, vegetables (sweet potatoes are great), quality grains and legumes (quinoa, kidney beans, oats, brown rice, etc.). Avoid the “carb loading” the night before. If you wait until the night before the race to try and top off your glycogen stores, it’s too late!! Not only will you NOT top off the glycogen, you will also likely have a stomach that is none too happy the following day. The night before, go with the same type of meal you have been consuming prior to your long training runs.

RACE DAY FUELING – This is the most important of all!! Most runners, SHOULD have their race day fueling strategy already figured out, prior to toeing the line for the race. With this being such an important subject, runners should have been experimenting and practicing this during their training buildup phases.

Because every body is different, so is every GI (GastroIntestinal tract). Fueling strategies that work for one, will not work for the other. This is why it is very important to play around with your face day fueling while in training. During your training, at least once per month, you should be experimenting with your race day strategy. The best place to do this, is during your long run.

Now, even though everyone is different, the body does process things similarly. During running, the average person can break down about 1 gram of carbohydrate per minute of activity. Thus, 60 grams per hour or roughly 240 calories per hour (approx 25 ounces of Gatorade or 2.5 GU’s).

So, lets say you come into the race with 2000 calories worth of stored muscle glycogen (granted, this number will vary among runners and their size). Keep in mind, you will be burning a ratio of fat calories to glycogen. Your level of fitness and your training, will dictate the ratio of fat:glycogen burn. Of that 2000 calories worth of glycogen, only around 45-50% of it is for leg muscle usage (the rest being stored in the liver for allocation to other body parts/organs). So, of the total 2000, only about 1000 can be used by the leg muscles. Keep in mind that these average calorie burn rates do not take into account intangibles such as wind, elevation, altitude, etc. Those factors will signifcantly change the burn rate, so be aware of that if you are running a course that has elevation, altitude or windy conditions.

So, if you are burning calories at a ratio of 65% glycogen (carbs) and 35% fat, and assuming you are burning 110 calories per mile, you’d be burning approx. 7o calories of glycogen and 40 calories of fat (PER MILE). Based on the assumed muscle glycogen storage from above (1000 calories), you’d be emptying the tanks somewhere around  mile 15. THIS is why consumption of carbohydrate is important during the race itself. This is also another reason why it is important to experiment in training, so that you have a good idea of your caloric and glycogen burn rate, based on your specific paces, size and ability to process the ingested carbs on the fly.

Here is a formula that will provide a decent approximation of calorie expenditure

Weight in pounds divided by a kilogram (2.2 pounds). Example: 150 pound runner/2.2kg = 68.18 kg. Now take the distance of the marathon in kilometers (42.195) and multiply by weight in kilos (68.18) = 2,877 calories that will be burned during your race. Then, one step further you can divide the total calories by miles (26.2), giving you an approximate burn of 110 calories per mile ran.

Taking this formula a step further, we can create a range of glycogen burn based on the various ratios of carb:fat being burned, dependent upon your V02 max output and how it equates to the increased burn of glycogen over fat.

60% Vo2 max = 55% glycogen and 45% fat

70% Vo2 max = 65% glycogen and 35% fat

80% Vo2 max = 75% glycogen and 25% fat

So, with those 3 assumed Vo2 outputs (consumption), the caloric burn range would be approx. 1500-2200 calories, 700 calories difference. That is the equivalent of 6-7 additional gels or an additional 100 ounces of Gatorade to make up for the difference.

How do we avoid this CRASH, BONK, HITTING OF THE WALL? Well, we do it via a combination of efforts. 1.) We ensure that our glycogen stores are at their highest, prior to the start of the race and 2.) We continue to consume roughly 200-300 calories (per hour) of quick absorbing sugars throughout the race.

So what do you consume during the race? Most of this is more a matter of preference, as well as what you have been practicing during your training. Many runners will scout out and determine what gels, sports drinks will be provide on the course, and will practice taking the same products during their training. Other runners will carry their own nutrition (my preferred method, as well as those I coach).

If you are the type of runner who takes from the course, understand a couple of things. First, aid stations are set up and manned by volunteers. They supply what is available to them, with no understanding of your individual requirements. Often, aid stations will provide some form of sport drink (Gatorade, Poweraid, etc.) and many times these drinks are a concentrate. Meaning, the drink is made on the fly and, ratios of the water to product will vary. Another thing to consider is that in many races, you will have a X Sport Drink table at X mile, and then a WATER ONLY table at X mile. So, if you are relying solely on the course to provide you with your calories, you best hope they get it right because 2 ounces in one cup is different than 4 ounces in another cup (this doesn’t account for how much you spill on your face and down your race singlet). It is also worth noting that these aid stations may provide some sort of gel, chew, etc. No matter how tempting, if you haven’t used it in training, it’s best to stay away from it. The last place you want to be the second half of the race is, the porta potty!!

Another thing to consider is, your individual “sweat rate” and how quickly you are getting rid of your electrolytes. This will vary with temperature changes but, even in ideal conditions, every runner has a different burn ratio of their stored electrolytes. This is another key reason that you should be experimenting with calorie and electrolyte supplementation during training.

Now, back to the race fueling! So, if you are the type of runner who carries his/her own fuel, what do you use? Me personally, I carry my own fuel/hydration and use a ratio to which I have been training with. In the past several races I have done, I was making my own sport drink and it worked great. That drink was a combination of fresh juices + powdered electrolytes and amino acids.

Most recently, I have started to use a product called Tailwind Nutrition. This product has one of the best calorie to electrolyte ratios I have seen thus far. It also tastes great and is very gentle on the stomach (a huge thing to consider if your GI can’t handle the typical sugars found in Gatorade or GU).


I also use Homeostasis Electrolytes to provide my body with the balanced ratio of electrolytes, especially on hot days. (NOTE – I do not mix the Homeostasis Electrolyte tabs with the TailWind Nutrition.) Whereas the HE will provide all of your electrolyte needs, it does not provide any form of calories/energy. So, in training, when I am teaching my body to burn higher ratios of fat to glycogen, I consume only water and the HE tabs. When racing for periods of 2 hours or more, I go with the TW Nutrition.


Hopefully, now that you have at least an idea of what/when/why you should be fueling during the race, lets touch on the last fueling strategy, PRE-RACE BREAKFAST! Though this should be a no-brainer, this one little area could be what makes or breaks you from having a great race. The morning of the race, you should eat the SAME thing that you were eating during your long training runs. Now is not the time to take advantage of the free continental breakfast at the hotel, “carbo load” or try some delicious looking pastry. This is the time to stick to your boring routine of whatever it was you had been eating on your training runs. Good choices (provided you have been eating them prior to) include, oatmeal with honey and a banana, bagel with peanut butter, fresh fruit (the less fibrous, the better).

Depending on your sleep scheduling and the amount of time alloted from the time you wake up to the time of your race start, you should consider calorie consumption based on grams consumed per hour.

1 hour prior to race = 50 grams of carbohydrates, 2 hours = 100, 3 hours = 150 and 4 hours = 200 grams of carbohydrates. Meaning, if you eat 4 hours before your race, you’d try to consume up to 200 grams of carbs (800 calories). If you wake up late and only have an hour before the start, it’s going to be around 50 grams (200 calories).

As mentioned throughout this post, you must experiment with all of this, based on your individual needs. Don’t do what everyone else does!! Find what works for you and continue tweaking and fine tuning it as necessary. No matter what strategy you decide on, stick to it and ensure that it suits your needs. Be smart and practice, practice, practice your race day nutrition. The last thing you want is to be well trained and then make a judgement error come race day. All that training will have done you no good if, you are running to every porta potty you pass because you had too much pasta the night before or, you tried something new on race day!

As always, Happy Training and Racing!! If you have any questions regarding any content within this post, feel free to contact me for further explanation/detail/correction.

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