Ironman Triathletes and Carbohydrate Loading

Carbohydrate loading is not necessarily the answer when it comes to increasing endurance for a marathon, half-ironman, or for an Ironman Triathlon.

Carbohydrate loading was in vogue back in the late 70’s and early 80’s when the running boom enveloped North America.

Triathlon followed closely on the heels of running when the Ironman hit the world stage of endurance sports in about the same time frame.

I remember in 1984 at Ironman Hawaii in Kona when Dave Scott was seen frequenting the local eateries and putting back huge portions of high carbohydrate salads and pasta.


In the early years of my running career there was this bizarre carbohydrate depletion-loading diet that was supposed to produce dramatic results on Marathon race-day.

If you race was on a Sunday for example, the idea was to do a 2-hour run the Sunday before the race and then not eat any carbohydrates until the following Thursday. I tried this once and by Thursday morning I barely had the energy to walk let alone run a marathon in three days.

On the Thursday morning the idea is to start putting back the carbohydrates like there is no tomorrow. You can actually feel your energy come back by the minute. The whole idea was to deplete your carbohydrates completely to better prepare yourself for late in the marathon when you run out of glycogen and hit the wall.

It is a dangerous diet and I don’t recommend it and the results really are not worth it.


You can carbo-load all you want the week before an Ironman, but there is a limit to the amount of glycogen your body will store so more is not necessarily better.

The average person has enough glycogen stores to last for a few hours of intense physical exertion and if you are not at the finish line when you run out you will hit the proverbial wall.

Read about the Ironman Triathlon Death March for more about what will be in store for you.

Few marathoners or Ironman triathletes comprehend the value of utilizing fat for fuel. In reality, our bodies store enough fuel to last for an entire Ironman Triathlon and then some. The trick is to train your body to burn fat as opposed to fuel.


The advent of the heart-rate monitor for endurance training was a Godsend and it’s almost startling how few triathletes make use of this amazing tool that has the potential to take their endurance levels to new heights and in the process dramatically effect their triathlon training and racing.

Basically a heart-rate monitor used to full potential in training will teach your body to burn fat for fuel as opposed to glycogen.

triathlon training with a heart rate monitor

A heart-rate monitor will teach your body to burn fat for fuel.

Proper use of a heart-rate monitor will also prevent you from over-extending yourself in training and will help prevent over-use injuries.

Have a look at this page on Heart Monitor Training that will walk you through the best way to make use of a heart-rate monitor if you want to dramatically increase your endurance.

Yes, of course you should still eat enough carbohydrates to top off your glycogen stores in the days before a major endurance race like an Ironman Triathlon, but balance that with burning fat for fuel and you might just have your best possible result by the end of the day.

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