Marathon Nutrition "Training"

Next Saturday, I'll set off at 6am to run 100 miles in the Umstead 100 Endurance Run in Raleigh, North Carolina. My legs are good (meaning my training has gone well) and my “head” is good (meaning I'm pretty confident about finishing in less than 24 hours) – but you never know how things will go until the actual day. Fingers crossed!

I will try to post periodic updates from the race via Twitter, Facebook, and LinkedIn – assuming there is decent cell coverage in Umstead State Park.

A few weeks ago, I posted on my Facebook page that Julie (my wife) and I had signed up to run the Utah Valley Marathon on June 11. We were joking around that the events are never “real” until you actually sign up for them – and even more so after you TELL other people that you’re doing them (then you’re REALLY committed when your friends know – so there’s no backing out)…

Since that post, I have received LOTS (and lots and lots) of questions from people asking me “how to train” and “what to eat” and “what to drink” for their own marathon attempts in 2011 – so I thought I’d use today’s blog to answer those questions and give some advice about what has helped get me through the dozen or so marathons that I’ve run (and 100+ triathlons and a handful of ultramarathons)…

Here are the “MOST Important Considerations” for anyone contemplating a marathon run:

1. Mileage (particularly your weekly LONG run, which can be SLOW)
2. Carbohydrate Intake
3. Hydration
4. PRACTICE (just like your running, you have to practice your nutrition)

Mileage

Probably to biggest mistake that runners make when training for a marathon is trying to run their weekly long run too fast. I like to tell the athletes who I coach that they want to avoid going “medium” intensity too often, because what they really need to spend enough time going HARD (and short) and enough time going EASY (and long). The hard/short workouts, such as interval training, help to develop your speed and lactate threshold – while the easy/long workouts, such as your weekly long runs, help to develop your ability to burn fat as a primary fuel source while also teaching you how to mentally deal with a sustained effort. I'll do a future article about the “training” side of marathon success – the rest of this article will focus on the some nutrition recommendations to help you complete 26.2 miles in one piece.

Carbohydrate Intake

Your TOTAL carbohydrate intake should be matched to your mileage.

• Example based on hard-training athlete = (5g carbohydrate /kg Body Weight) = example 160lb man = 72.7kg * 5g = 364g carbs/day (1,456 kcal = 14.5 miles).
• The more miles you are running each week, the more carbohydrate you'll need to be consuming to sustain your training and keep you glycogen levels topped off.
• It is typically better to “match” carb intake to mileage and to symptoms (fatigue, irritability, weight gain/loss) – tweaking slightly each day/week as you go…

Do you need to “fuel” immediately after exercise? 

There is a lot of talk among recreational runners about the “need” to “fuel” (with a meal or sports drink) immediately after exercise to enhance their glycogen storage. While it is true that your body will produce and store more glycogen (the storage form of glucose in liver and muscle tissue) in the 2-hours immediately post-exercise, there is no compelling reason for most recreational runners to bother with “immediate” fueling UNLESS they are doing HARD workouts back-to-back (such as two interval sessions in one day or on following days). If, like most recreational runners, you alternate hard/easy training days, there is not any significant benefit from fueling “immediately” after your workout – you'll do just fine eating at your next meal. Eating “later” instead of “immediately” after your runs might actually help you drop a few pounds of body fat, as I cover in a recent article (http://running.competitor.com/2010/05/features/now-or-later_10020).

Should you carbo-load? 

Maybe – but you need to practice it before you try it “for real” in advance of your upcoming marathon. A good time to practice carbohydrate loading is for one or two of your weekly long runs – just to see how your body “likes” it (or not).

The main reason to consider carb-loading is that it may help enhance endurance and  improve performance – so you're less likely to “hit the wall” (which often happens to a lot of runners somewhere between mile 20 and the finish line at mile 26.2 – see below for “why” you hit the wall at this point of the marathon).

One reason to practice carb-loading is to find out whether or not your body develops any of the possible side-effects that are common with bumping up your carb intake. These side-effects can include bloating, constipation, and heavy legs – none of which you want to experience for the first time on your big race day.

Whether or not you do a true “carbo-load” (2-3 days of hard or long training while you consume very little carbohydrates – followed by 2-3 days of light/no training while you eat lots of carbs), you will definitely want to eat a high-carb meal on the night before your marathon (e.g. pasta dinner). This will at least give you the carbohydrates to top-off your glycogen levels for your big race the next day.

Why do you “hit the wall” at 20 miles?

“Hitting the wall” typically describes a depletion of muscle glycogen stores – at which point your exercise intensity drops to a very low level because you're basically “out” of readily-available sugar to fuel intense muscle activity. This is a little different than “bonking” which generally refers to a depletion of liver glycogen stores – while muscle glycogen stores may still be abundant. When liver glycogen drops, exercise intensity also needs to drop because you can't maintain blood sugar levels. The biggest difference between bonking and hitting the wall may be that you can “come back” from bonking by eating some carbs (sports drink, gels, real food like a PB&J sandwich) to get your blood sugar levels back up – whereas hitting the wall means that you're down for the day (because replenishing muscle glycogen takes at least several hours).

Bonking can happen at any time if your fueling strategy is inadequate (e.g. skipping breakfast and lunch before a long afternoon run or ride) – while hitting the wall most often occurs right around the 20-mile mark for most marathon runners. The 20-mile mark is a bit magical because it represents the mileage limit for our typical fuel stores. We can store approximately 100 grams of glycogen in the liver (400 calories) and another 400 grams in the muscles (1,600 calories) – for a total of about 2,000 calories of stored sugar. Considering the general guideline that running burns about 100 calories per mile, we see that 20 miles x 100 calories will burn-up every bit of our glycogen stores – leaving us with “nothing” to get us across those last 6.2 miles to the finish line. Obviously, we need a strategy to “make up” for that gap of about 600 calories – and this is where your training and your race-day nutrition plan will make the difference.

From a “training” perspective, the more you can teach your body to “spare” your limited glycogen stores (and burn fat instead) the more glycogen you're likely to have left in the closing miles of your marathon. From a “nutrition” perspective, you'll need to consume some of these 600-or-so calories in the form of sports drink, gels, or other source of carbs that you can easily swallow and digest while you're running. Deciding what to eat will be determined in large part by personal preferences such as “tolerability” - how much and what type of foods you can eat while running without suffering stomach upset. At marathon pace, I might take 2 or 3 gels (200-300 calories), but cannot tolerate much more than that without feeling nauseous (see below for my personal marathon fueling strategy). 

Hydration

Hydration drinks (Gatorade and related beverages) are intended primarily to replace fluid and electrolytes, and are thus different from “Carbohydrate” drinks, which are intended primarily to replace carbohydrates. Obviously, there is a bit of overlap between the two types of drinks, because electrolytes and small amounts of glucose will improve the  absorption and retention of water – but when carb-concentration gets too high in a drink mix, it will start to impede water/electrolyte absorption. Virtually all of the hydration beverages (Gatorade, Cytomax, etc) are “better” than water – but they are all pretty much “equivalent” when compared to each other. You really need to PRACTICE with the different beverage options to see which one you like best in terms of taste and gut tolerance. A good idea is to find out what beverage will be at the aid stations at your target marathon – and then train with that drink. If you don't like the drink that will be on-course, then you'll have to come up with a strategy to either carry your own hydration beverage or have someone meetr you along the course to hand-up your drinks. I use a lot of different hydration beverages in my own training – I like Gatorade and Cytomax and use them quite frequently, but one of my personal favorites lately is PowerBar's “Perform” drink because it contains a 2:1 glucose:fructose blend that seems to agree with my stomach during long events – and it is the drink used on-course in the Ironman-series events (and it's convenient to use the same drink that will be at all the aid stations).

One last note about hydration and carb beverages. It has become very popular – almost trendy – in the last few years for companies to add different levels of protein to their drink mixes. This idea is based on some sloppy understanding of exercise physiology that has perpetuated a misbelief that you “need” protein during your endurance event – which is NOT true. Let me be very clear = you DO NOT need (or want) any protein in your “during exercise” beverage. You want your “during marathon” beverage to contain 3 things: Water + Electrolytes + Sugar (glucose/fructose/maltodextrin) – nothing else matters. The only exception to the “no protein” recommendation is for athletes going “longer” than the marathon distance – so if you're out there for longer than 3 hours, then a little bit of protein can provide benefits in terms of hunger control, fatigue prevention, etc. - but NOT for your marathon training or racing.

Suggested Race Plan (to balance energy and fluid delivery)

1. Eat a balanced breakfast (2-3hours prior to your start). Do not make the mistake that SO many endurance athletes make, of eating anything substantial (even a gel) within the 30-120minute window prior to a race. This is the “black hole” for eating that you MUST avoid – you can eat 2 or more hours before your start – or within 30 minutes or less – but not between 30-120min because if you eat during this black hole period, you have a very high risk of experiencing an insulin-induced bonk, or “rebound hypoglycemia” during your race (insulin spikes and blood sugar drops and your performance tanks – more on this in a future blog).
2. During the half-hour prior to start, drink a bottle (12-16 ounces) of Gatorade or similar beverage (this is not enough calories/sugar to stimulate an insulin response – so don't worry about the “black hole” warning above). This approach of sipping a bottle will help to top-off your hydration before your start.
3. For the first 60-90min of the marathon, drink 2-4 ounces of Gatorade (or whatever drink) every 10-15min – this means you're taking a few gulps at each aid station. Do not start eating yet – you will not oxidize more than 20-30g (80-120 calories) of ingested carbs during this period anyway – so no need to “stress” your gut at this point. Remember that you also have the carbs/calories from your breakfast that are “in your system” at this point. After half-way point (13.1 miles), begin ingesting more carbohydrate and sodium (gels are perfect here – about 100kcal – take 1 gel pak about every 30-40min after halfway) to hold off the “wall” and allow you to stay strong in the last miles to the finish.

My marathon-nutrition plan as an example:

1. Breakfast (in hotel room, 2-3 hours prior to race start) = 2 packs of instant oatmeal with splash of half/half (~300 calories with 62g carbs), 1 medium banana (100 calories with 25g carbs), coffee, glass of water. This 400 calories and 87g of carbs almost “makes up” for my 600-calorie deficit (between stored glycogen and what I “need” over 26 miles) before hitting the wall at mile 20 (I need about 200 more)…
2. On the way to the start (sip on bottle of Gatorade) – finish it before start...
3. Drink half cup of Gatorade at each aid station for first half (13.1 miles in 1:30)...
4. Drink half cup of Gatorade at each aid station for 2^nd half – EXCEPT for “gel stations” where I drink ½-cup of water...
   1. For me, the 2^nd half of the marathon takes 1:40-2:00 (total time of 3:10–3:30 depending on the course, so I need 2-3 gels.
5. FIND OUT were the gels will be available (some marathons only provide gels at certain aid stations - or carry a couple with you). I carry 2, just in case, and typically consume one at miles 14, 18, and 22 (w/H20). These 200-300 calories of carbs from gels closes my 200-calorie “carb deficit” to help me finish strong (fingers always crossed)…

I have followed this general nutrition plan for many years and through hundreds of marathons and triathlons – and it has never failed me. I hope the recommendations above will help to demystify some of the questions around what to eat and when to eat for your next marathon. Good luck – and finish strong!

Thanks for reading,

Shawn

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Shawn M. Talbott, Ph.D.

C.E.O. (Chief Endurance Officer)

Wicked Fast Sports Nutrition

648 E Rocky Knoll

Draper, UT 84020

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Shawn@WickedFastSN.com

www.WickedFastSportsNutrition.com

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