Fueling will make or break your marathon, no matter how well you've trained. In this guide, Kim Clark walks you through how to build yours — from your pre-race breakfast to your gel strategy to managing electrolytes and hydration on course.
Fueling will make or break your race. We don't want to spend so much time on our training & then sabotage our race with underfueling. During the Osaka Marathon, I took 111g of fuel an hour, and it really helped me to maximize what my body could do that day.
First Breakfast!
Boston and other World Marathon Majors have a later start time than most marathons due to the size and logistics of the race. You'll still have to wake up pretty early to get to the start, so YOU WILL NEED TO EAT BREAKFAST. In order to have a game plan of WHAT to eat and WHEN, you'll want to practice this in training multiple times.
Try different things for breakfast and note what works well for you, and just as importantly, what doesn't!
Vary the timing of breakfast from the start of your run and note what works best. (If you plan to warm up on race day, time your breakfast from your warmup when you actually start running, not the race start time.)
Count the time that you FINISH eating to the time you START running.
Whenever possible, bring your food with you so you don't have to rely on finding what you need in Boston.
My Breakfast
I don't like to eat too much, especially on race morning. I have a serving of The Feed Lab High-Carb Drink Mix & 1 or 2 Honey Stinger Waffles (Gluten Free - the Cookies & Cream are my faves!)
Eating a good breakfast can also put your mind at ease that your energy stores are topped off, and now all you need to do is focus on your fueling during the race!
So how much do you take?
The short answer is: as much as your body can process and no more.
When you exceed the amount of carbs your stomach can process, you will cause GI distress. This is the most important aspect of practicing fueling since GI distress will absolutely ruin your ability to perform your best.
As you practice fueling, you will need to practice taking gels and drinks at different intervals- 20 minutes, 30 minutes, etc., and how often you take in fuel will also be dependent on how many carbs you're taking in each time.
START BY TAKING A GEL EVERY 30 MINUTES
This is a conservative place to start and allows your body to get used to taking in carbs and digesting regularly during your long run. Including a gel right as you start your run, So for a 2 hour long run, that's 4 gels with your last gel at 90 minutes. You can also take a 5th gel at the end of the run just for practice & recovery.
Work up to every 20-25 minutes. As your body gets better at processing carbs on the run, increase the amount of fuel you are taking first by taking fuel more frequently rather than in larger quantities.
Boston Pro Tip #1
As you practice taking gels in training, vary the timing and also practice taking gels on different grades. If you have trouble getting a gel down while going uphill, you don't want to try to take a gel halfway up Heartbreak Hill just because it's exactly 30 minutes since your last. You might want to take that gel before you hit the hill, or wait until you're over the top!
START BY AIMING FOR 60G OF CARBS / HOUR
If each gel has 30g of carbs, then 1 gel every 30 minutes is 60g per hour. If your gel is only 20g of carbs, then you can start with a gel every 30 minutes but should work towards a gel every 20 minutes.
INCREASE TO UP TO 100G / HOUR
As your stomach gets stronger, begin to increase your carbs first by taking gels more frequently. Eventually, you will be able to process more carbs at one time so something with more carbs per gel will be easier to do and even taking additional carbs in your drink.
CAFFEINE
Try taking caffeine in different intervals as well. Start with 1-2 gels during your long run toward the middle/end and work towards taking caffeine earlier to see how it affects your stomach and performance. Be careful not to take a pre-workout supplement AND a caffeine gel to start your run!
Boston Pro Tip #2
When you are released from the staging area to go to the start line, corrals are a great time to take your 2Before & Nitric Oxide Pro! This allows just enough time for it to be absorbed and give you that extra boost right from the start!
PRE-WORKOUT
2BEFORE
A good pre-workout supplement can help you have better, more consistent workouts and races.
I've been taking 2Before for years now. It's the perfect boost for consistent performance!
NITRIC OXIDE PRO
For more of a boost on race day and key workout sessions, nitric oxide increases blood flow to muscles, enhancing endurance and faster recovery. This is a great supplement to save for special occasions to see a big difference!
I've had my best half marathons in 18 months, even after some time off and minimal training!
HYDRATE
You MUST be hydrated in order for your body to absorb the carbs. Generally, you need about 12 ounces of water per 30g of carbs. You don't have to chug all your water right as you take your gel, but you should be drinking that much in between each gel.
Boston Pro Tip #3
Gatorade & water will be served on course at every mile mark. Know that Gatorade has electrolytes, but it also has CARBS and should be factored into your total carb consumption! Water obviously doesn't have carbs, but it also doesn't have electrolytes, so if you're only going to drink water on course, then you need to be getting your electrolytes somewhere else, like from your gels.
PRACTICE
Perfecting your fueling plan for race day takes a lot of practice, honestly, a lot of trial and error. You have to discover what types of fuel your body digests well, how much you can take, and which ones make you feel the strongest, especially later in the run.
As you practice in training, take note of what you are doing and make adjustments until you find a pattern of fuel source, quantity, and timing that allows you to get in the most fuel without causing GI distress.
What time did you take them? (i.e., 45 minutes into the run, 60 minutes into the run, 45 and 90 minutes?)
What mile did you take them? (3 miles into an easy run won't be the same amount of time as 3 miles into a faster-paced run)
How many grams of carbs did you take each time?
How much fluid were you taking in as well?
Did you drink or take a gel before your run? How long before?
Did you notice any differences in performance before or after?
Did you notice anything with your stomach? Good or bad?
Did you take caffeine? How much? And when?
Did you take other ingredients like BCAAs? How much? And when?
What brand/ ingredients did you take?
My Favorites
I've been really diligent about practicing my fueling in the last year, more than I have before, and have been able to dial in what works best for me, and I can feel the difference! These are my personal preferences for fueling, and while these might not all work perfectly for you, they'll provide a starting point for you to find what does work.
GELS
I prefer “high carb” gels. Gels with fewer carbs you'll have to take more often, which is fine if you want to take smaller quantities at a time, but I don't want my effort to be interrupted by fueling so often, so the more carbs I can get with a single gel, the better.
My favorite gels recently are SantaMadre (the mint is so refreshing!) and Victus. There are plenty more to try, but I've been able to take in a lot more carbs with these gels and no stomach issues!
My favorite feature when I'm shopping for gels on The Feed is the "high carb" filter so I can see all the gels with 40+ grams of carbs per gel in one place and eliminate all others.
Boston Pro Tip #4:
Maurten will be served on the race course at miles 12, 17 & 21. It's a good idea to try Maurten at least a few times in training to see how it works for your body. You could plan to carry a few fewer gels if you know you want to take Maurten from the aid stations. Even if Plan A is to only use your own gels, you'll know if it's an option as a backup plan (or definitely NOT an option) if you've tested it in training.
CARB DRINKS
I also drink high-carb drinks at the start of a workout or race, and also during when possible. I've really liked Precision Fuel Carb Only Drink Mix and The Feed Lab High-Carb Drink Mix.
ELECTROLYTES
You can get electrolytes in your gels and/or your carb drink mix, or you can drink them separately. On race day, when relying on the fluids on course, it's much easier to get electrolytes from gels and just drink water.
I've been loving the Cadence 500! During the Sevilla Marathon, I was feeling some cramping coming on and was able to drink a cadence which completely saved my race!!
Boston Pro Tip #5:
Boston can be very exciting and even overwhelming at many different points on the course. Don't let the excitement stop you from executing your race, especially your fueling plan. Enjoy all the cheers and the energy, but also stay focused on your race plan!
