Some will argue that you should do your long runs in marathon training on an empty stomach, to practice depleting your body of glycogen, not just to prepare for the experience of doing the same in the longest run itself but to also prime your glycogen stores to hyper-compensate and hopefully store more glycogen than before.
Some will argue that you should eat a good meal before long runs and stay completely fueled, in order to maximize your performance on these runs, avoid bonking, and maximize the potential physiological hypertrophy (growth) from these long runs.
Some will argue that you should practice doing it both ways, that both approaches have their respective benefits and that doing both will maximize your development prior to the taper and the longest run itself.
What is my point of view? I’ll be honest: My point of view has gone back and forth. I have trained with long runs on nothing more than a small meal beforehand, to push myself to the limit otherwise cold turkey. I have eaten a full breakfast, then brought 2 liters of Gatorade in a hydration pack and fueled religiously throughout the run, even stopping to eat or drink during the workout as needed.
But now, when it comes to the best way to do marathon training long runs, I come back to a semi-rhetorical question:
What is the primary goal of a marathon training long run?
To be non-rhetorical, the base answer is: To train to run the marathon. Let’s break down defining the key terms.
Train: Building and harnessing the ability to do the goal task at hand through defined, organized practice and repetition.
Ability to do the goal task: Capability to Run the Marathon.
Run the Marathon: Run 26.22 miles in one go in a designated place at a designated time without substantial breaks in action, under the circumstances unique to that particular situation, as fast as you reasonably can.
The Circumstances: You will be running along with several other individuals along a pre-determined 26.2 mile course of varying dimensions and elevations, a course that (with rare exceptions) will have stations interspersed every few miles with amenities such as water, electrolyte fluid, portable toilets, helpful people, and at times food, medical help, other amenities such as gels or food, etc.
A lot of people understand that you run long to prepare to run long. Some more experienced runners also realize that you may also plan to do the longest run at a faster pace than your typical training run, and therefore do at least part of their long runs at a faster pace consistent with the pacing they expect to utilize on race day.
People give less than rudimentary thought to the idea of practicing fueling on these long runs. At the very least, they understand that they may need fuel on these runs, so they figure they’re killing two birds with one stone. But really, they’re only killing 1.5 birds.
There’s rarely any organization or critical thinking to applying the practice fueling on the long runs. It’s just done in a workout or two to work on it. Or they fuel and hydrate when they think to do it or feel they need it. It’s a generally applied practice without much thought beyond that.
Is that a problem? Well, I wouldn’t say so, but I will say it’s a missed opportunity to maximize your preparation for the race.
Unless you’re carrying your own fluid and fuel and never bother with designated aid stations at the race, you will likely take fluid and fuel (maybe even use the toilet) at these stations. The spacing of these stations isn’t going to vary once the final course map is confirmed. They will always be at a specific point on the course.
If you’re taking fluid whenever you feel like it on training runs, it’s going to feel foreign and possibly unduly challenging on race day to have to run X miles or kilometers to get to your next opportunity to take fluid. The marathon is already hard enough without the potential to feel strained or dehydrated in the first half of the race.
Or, if you do your training runs dry (no fuel or fluid), but you take fluid and fuel at the stations on race day… your stomach may not be accustomed or otherwise ready to handle that while running, and that could negatively impact your performance.
What if on your training runs you practice taking fluid only after having run a distance or time equal to the amount of time it will take you to get to the next aid station?
For example, this May, I am running the 2020 Vancouver Marathon. They are using the same course they’ve used in previous years, so I know the distance between the start line, the 1st aid station, and every station thereafter.
I also know my planned goal pace, and thus can determine roughly how long it should take me to get to aid station 1, aid station 2, etc. I can really nitpick and factor in what elevation changes to expect between stations as well, but for this topic let’s stick to just knowing the distance between aid stations.
I figure it will take about 18 minutes at goal pace to get from the start line to the 1st station. From there, it will take about 15 minutes to get to the next station. For the most part, it should take 15 minutes between most stations, though I’ve noted a few closely placed stations where it should maybe take closer to 10 minutes.
I can actually take this information and apply it to my long runs. I can not only practice the run itself, but carry fluid/fuel and practice taking in fluid during each of the times I project to reach an aid station. For example, I can start the run, take fluid at 18 minutes (when I would expect to reach the 1st aid station), at 33 minutes (when I expect to reach the 2nd station), and so on. I can also work out when I plan to take my fuel (e.g. gels, food), and also practice taking it in during those times.
However much fluid or whatever fuel you plan to take… make sure to bring it with you on the run in a belt/pack. The average aid station cup contains about 4oz of fluid, so for example if you know your long run will last the amount of time needed to cover 5 aid stations, bring at least 20oz of fluid with you. If you know on race day you’ll probably take a gel within those 5 stations, bring a gel. If you know you’d take two gels within those 5 stations, bring two gels. Take fluid and fuel exactly in the order you would as you estimate “reaching” those “stations”.
You can also physically practice how you plan to go through the stations. Will you try to keep running while taking fluid? Will you slow down and walk? Will you take a gel every 3rd station or so? Use the toilet? Whatever you physically intend to do at the stations, go ahead and do it during these “stops”:
Walk through station 1 at 18:00 as you would on race day. Tear open your gel and wolf it down at 33:00 as you “reach” station 2. Stop and take a breath as you would at station 4 at 1:10:00 into the run. Use the toilet once you hit your 6th stop at 1:33:00. And so on.
This is akin to how theatre performers rehearse for their shows. Along with learning their lines and whatever find-your-emotional-place method acting they do in their minds… they just as importantly “block” the entire play, figuring out where physically they are going to go every moment of the play, and then they practice their every move. By show day, every bit of it flows into place as planned.
I don’t expect you to memorize every step of a 26 mile run. What’s the fun in that anyway, right? However, the longest run will be full of limit-testing challenges, and whatever else you can do to help mentally and physiologically prepare yourself to handle the challenge is only going to improve your race day experience. Practicing the mechanics and timing of your aid station stops will help eliminate a key race-day worry. Along with aerobically practicing to run the longer distances, the long run is also a chance to practice race day hydration and fueling.
Sure, you may not necessarily need the fuel or fluid to finish that particular training run, but you definitely do gain a lot from practicing the mechanics and physiological handling of that fueling and hydration. It becomes less of an adjustment on race day, if it’s any real adjustment at all. It’s one less (important) thing to worry about.
One key: I advise usually doing this by expected time between stations rather than actual distance. From my view, since I will run the marathon faster than I will run my training runs, it may not make sense to practice taking fluid by distance, as it will take longer in training to cover the physical distance equal to that between the start and aid station 1. It would throw me off on race day to get there faster, and my body may not be trained to handle the faster influx of fluid and fuel.
The only time I’d recommend doing these fuel/fluid station breaks by distance is when doing actual marathon pace or tempo runs, when you actually are covering distance in the expected goal time. And yes, I’d certainly recommend practicing this aid station “rehearsal” on your marathon pace runs, as well as longer runs.
You also don’t necessarily have to practice just from the start to whatever aid stations you can simulate covering in the time it takes to do your long run. You could “rehearse” any stage of the race this way. You could decide to simulate the last several aid stations on the run, to simulate what fueling at the finish will feel like.
If you did want to deplete your body for training purposes but still wanted to practice this, you could possibly do this fluid/fuel timing for part of the long run, and just do the rest of the run without any fuel. For example, practice 4-5 key stations (maybe your planned route matches a middle segment of the course), and then go without fuel or relax and fuel as needed the rest of the way.
It’s completely up to you how to apply these ideas. You can apply them verbatim, apply them loosely, or ignore them and not apply them much at all.
Either way, applying your knowledge of the course with some critical thinking can give you another opportunity to practice getting comfortable with an underrated key element on race day: The timing of fluids and fuel from the aid stations.