Ironman fueling strategy calculation

What has your strategy been on your long rides up to now?  Have you been well fueled at the end of a 6 hr ride or were you really flat?  That should give you some indication.

Good point. Actually I do not know really what to put.

I would like to be conservative, putting something higher than expected but maybe 85% is really too much.

What do you think?

My max heart rate is 183 on the run which is the highest and here probably I need to refer to that one and not to the bike.

85% of 183 is 147 which can be few beats above if I race properly on the IM.

A realistic one would be 80% for me and it will move down to 359 which is what I was thinking to (without this tool). 

Honestly I can't trust my feeling during my long rides only. Those long rides are very important (for my opinion) to EXCLUDE what should not be done.

About food and liquid quantity, I think experience on the races is more important and I will never reproduce the same feelings in the trainings.

Again, I am selecting the best bars, gels, sport drinks and whatever fits to my stomach in those long rides. Not the quantity. I am not eating 350kcal per hour on those rides! 

If you think you might eat that much during your race, you should.

Actually I opened this thread because I don't know and it is not a matter of feeling, it is a matter of theory. There should be a minimum and a maximum.

If you go below the minimum, you are going to stop on the run.

If you go above the maximum, you are going to have stomach problem.

Assuming of course that the food and drinks you are using are tested on you and work great 

The only way to put theory to practice is to test it out.  IMO, Nutrition is what you test in training.  If your body can't absorb 400 Kcal on the bike in training, it won't be able to during the race.  You can find that max/min if you want, but do it by testing it on your training rides.  The last place you want to find out it doesn't work is on race day.

For reference, I have athletes that range from up to 500 Kcal to 250 Kcal for the same intensity and body type.  The only way to find out is to test it and keep track.  Good luck!

Just remember the adage...."Nothing new on race day"

Theory is all well and good.  But practice is what matters.  Use the theory to establish some ranges.  Use practice to see how YOUR body handles those ranges--preferably under a variety of conditions.  (Again, note how many assumptions you have to make to arrive at your 'ideal' calories in that calculator.  Too many for it to be 'accurate'.)

The food and drinks you use may 'work great' for a few hours at a low-moderate intake.  For multiple hours, at a higher intake level, perhaps not so much.  There's only so much 'science' to this.  In the end, it's at least as much 'art'.

I used the calculator and set my targets for the race, based on my training and it came out almost spot on.  I've been training for 200cal/hr and that was the recommended value from the calculator. 

Nice sanity check.

Was it for the half ironman? 

As JK mentioned, there are several assumptions that are coming into play with this calculator including maxHR.  If I were you, I would forget the calculator and start experimenting on yourself since you will be racing, not the calculator.

People handle race day nutrition very differently and you need to see what is going to work for you.  So on your long workouts, you need to fuel as you plan on race day; I would start at 300cal/hr on the bike and 200cal/hr on the run and adjust from there.  Also, I would keep things as simple as possible as right now you are managing three different products to get your calories and this could easily be simplified to one or two.

Also, some of the best advice I've seen about IM nutrition was from RocketMan; basically he said, if it tastes great after six hours of training, it might be okay after ten hours of racing.

Good luck,

Shane

Ok maybe I need to experiment on the bike but for sure, I will not eat 200kcal/hr on the run!

Tipically, on standalone marathons, I eat max 2 gels and sometimes 1 only, with a couple of sips to water on the way. I do not tolerate anything more than that on the run.

It should not change on the IM run leg.

Your intensity on the IM run leg is going to be vastly different than what it is during a standalone marathon.  In addition to that, the time to run the two is probably going to be at least 30' different (at best) so you can't really approach your nutrition in the same way.

Also, keep in mind that you are fighting a losing battle when it comes to race day nutrition; you can't replace what you are expending so the goal is to keep putting enough fuel into your body to allow you to finish the race.  While it is definitely possible to overfuel, even planning on a gel an hour on the run is not going to be a bad place to start.

Shane

I agree with you and you should add that the type of fuel is different too!

I consider to run my IM marathon mostly taking energy from fats, at least much more than a standalone marathon.

If I can run the mary in 2h50' with 2 gels, if I run the IM marathon in 4h00, in theory, I can go ahead with nothing else than my body energy! For sure less than 2 gels!

Do you agree?

I think that, I can be 2 days without food and then run 26miles wih just water in 4hrs. Pretty sure on that.

The problem arises if I finish my glycogen on the bike (due to poor nutrition and due to too high intensity) and then I start running the marathon with a pace for 3h20' (for example). I will hit soon the wall because at 3h20 I need less fats for running and more carbs which are not there.

I think you should try that.  My guess is you won't be close to 4hrs.  And may not finish.

I don't think I could disagree more with the idea of running an IM marathon with zero nutrition.  Typically an athlete will have stored fuel for an hour and a half to two hours - after that some fuel will be required (hence the two gels for your marathon).  The longer the event takes, the more you have to consume - when you start the IM marathon, your stored glycogen is gone ad if you don't take is some carbs, you are at best setting up a long walk.

Shane

I consider to run my IM marathon mostly taking energy from fats, at least much more than a standalone marathon. >>> why? do you incorrectly think that by providing more fat as means of fuel for your body will use it to propel you through the race and conserving glycogen at the same time? sorry it doesn't work that way, still your body has enough fat to complete an IM without you ingesting any

If I can run the mary in 2h50' with 2 gels, if I run the IM marathon in 4h00, in theory, I can go ahead with nothing else than my body energy! For sure less than 2 gels! >>> I think you should try that at your IM and let us know how it works

Do you agree? >>> no

The problem arises if I finish my glycogen on the bike (due to poor nutrition and due to too high intensity) and then I start running the marathon with a pace for 3h20' (for example). I will hit soon the wall because at 3h20 I need less fats for running and more carbs which are not there. >>> if you go through all your glycogen at any point you won't be moving forward at all, in fact you might be death