I always scratch my head when people give the above justification (I’ll run out of glycogen anyway) for not carbohydrate loading for ultramarathons. But, to me, the fact that you WILL run out of glycogen is even MORE of a reason to come into the race topped off, not less of one. On the other hand, in a 100-miler, you will bonk at some point IF you’re trying to run at a relatively challenging pace. True, in a “shorter” event like a marathon, you should be able to prevent total depletion (bonking) by carb-loading and taking in an easily manageable amount of carbs during the race. For this reason, some people ask, is carbohydrate loading even necessary since I’m going to totally deplete myself of glycogen anyway? My answer would be yes, of course. That is, even IF you fuel appropriately during that event AND carb-load prior. If you’re running an ultramarathon, there’s a good chance you will completely deplete your glycogen at some time during the event. Carbohydrate Loading for Ultramarathons – Common Questions and Best Practices Is carbohydrate loading for ultramarathons necessary? In addition, we will shed some light on the best practices an ultra-runner can utilize to make sure they are “topped off” come race day. The purpose of this blog is to answer some of these common questions surrounding carbohydrate loading for ultramarathons. Is carbohydrate loading for ultramarathons (like a 100-miler) even necessary since most ultra-runners will totally deplete glycogen at some point during the race anyway? Is carbohydrate loading for ultramarathons the same as for shorter events, like, say, a marathon? I have heard several questions regarding carbohydrate loading for ultramarathons.

Carbohydrate loading, also called glycogen supercompensation, tops off glycogen stores so an endurance athlete can enter an event with as much fuel for their effort as possible.

If you are an ultra-runner, you likely already know the premise behind carb-loading and why endurance athletes do so.

Carb loading