Found a mention of a low carb option called Spike-Free (not currently avaiable as they’re researching new recipes) that included a document that has some interesting information in it. As always take anything you read on the Internet (including this site) with a very large grain of salt.
The purpose of the document is to obviously support their theories and coincidentally their products on the best option for fueling. It’s the same thing that eFuel and [insert your favorite fuel company] does. Note that pre-low carb my favorite fuel was the eFuel gels and drink mixes. They worked very well for me, better than anything I’ve tried and I’ve tried a lot (most commercial and DIY options).
But now that we’re doing low-carb, me primarily as it’s the easiest way for me to lose weight which I’m trying to drop lbs for our 50’s, sugar based options are off the table.
But the interesting thing in their proposed science for me was that after 2-3 hours of training/racing your body will have consumed all free glycogen in the system which makes sense even for people who are carb loaders. There’s only so much storage room in the human body and 3 hours of running burns through that for the average person. This is the source of the 20 mile wall/bonk (for the average elite). For me I burn through glycogen stores a fair bit earlier, it takes a lot more energy to push a Semi Tractor up a hill than a Porsche.
But your body needs carbs/glycogen. This is why if you were to cut out every carb down to 0 intake your body has a mechanism to start turning protein into a carb substitute, even consuming itself if it has to. So you do need to intake ‘some’ carbs when you burn them all out because during extreme exertion your body has a hard time doing everything at once. There’s only so many resources to allocate to keeping you moving, your organs functioning properly, your brain working right, processing nutrition and water, cleaning your blood of toxins.
Long story not very short, the folks at Spike Free allege that once you’ve run the tank dry then you can consume carbs to some degree, need to in fact. And most importantly they allege that at this point certain carbs are processed directly into energy and bypass the insulin reaction with all the bad things that brings to a low carb running on fats and ketones type runner.
And this is what I find interesting as we’ve discussed how we’re going to fuel low carb on our long runs/races. The Spike Free’s folks thoughts that we should be able to add some basic carbs like potatoes or a banana an hour, need to in fact, could prove pretty important in our abilities to do these ultra runs with some measure of enjoyment.
We’re already at the the 3-5 hour long run point in our training and those are just going to keep getting longer so we have plenty of opportunity to test it out.
If it works we’ll let you know. And if it doesn’t work we’ll let you know that as well.