At SFuels, we’ve been advising a unique approach to fuel athletes in training and racing, since the day we opened our doors. More specifically, we formulated products for changing physiology from rest, to long-slow training, to high-intensity training and racing.

So what’s the rationale?

Well, much changes in our energy-processing physiology between sitting on a couch and after an hour or so of aerobic exercise.  It’s commonly assumed, that how our body moves glucose out of the blood and into the muscle cells, is a singular and fixed process at rest, and during exercise. But it’s not at all true. In high-level concepts, here’s what actually happens.

At rest, when we drink some juice, or any form of carbohydrate, (particularly simple sugars, like sucrose, glucose, fructose, maltodextrin) sugars are rapidly absorbed into the bloodstream, and then move through the liver.  These sugars (glucose), then trigger our pancreas to produce and push insulin into the bloodstream.  By design, insulin will interface with muscle cells and trigger them to open up glucose channels, allowing glucose to flow into the muscle cell. Conversely, insulin also informs fat cells NOT to oxidize or breakdown fat for energy.

Now, let’s look at what happens after an hour or so, of aerobic exercise.

Repeated muscle contractions over an extended period release chemicals like Calcium, nitric oxide, and free-radicals. While still being researched, it’s thought that these chemicals are responsible for triggering the movement of cell-transporters (namely, Glut-4) inside the cell, to move to the edge of the muscle cell, and open up glucose channels, allowing glucose to flow into the cell – without insulin.

At this point, you now have an optimized physiology for endurance exercise, whereby the physiology is optimized to simultaneously oxidize both carbohydrate and fat (fatty acids) substrates inside muscle cells for fuel. 

But, here’s the issue –

For the past 30 years of carbohydrate-led fueling guidance, athletes have been asked to start taking carbs, the night before, the morning of, at the start of the race, and through the race.  As underlined above, any intake of carbohydrate, particularly the refined types pre-training, or pre-race, will instruct the fat-oxidation machinery to switch off.  This effectively blunts your physiology, making the athlete far more dependent on carbohydrate stores and intakes to perform best in their training, or racing goals.

Furthermore, research papers have highlighted that fructose and maltodextrin consumption (in many energy drinks, gels, and bars) suppresses Glut-4, the very muscle transporter you need to bring glucose into the muscle cell. So stay way clear of those two ingredients in your fueling, and diet.

So what to do,

In our QuickStart Guide (download here), in the racing and high-intensity page, you will find a chart (like below) that highlights the need to shift from a NO-Carb Fat+Electrolyte fuel, to a Carb+Fat+Electrolyte fuel – as you move from pre-training/pre-racing, the 1st hour, and then onto the 2nd hour and beyond.  By doing this, you’re training the body to switch on simultaneous carb-fat substrate oxidation for fueling.

ProductChoice2You will see in this chart, that as length and/or intensity of your training increases – your fueling will shift from our SFuels Train Fuels (No Carb. Only Fat, Electrolytes), to our SFuels Race+ Fuels (Carb+Fat+Electrolytes).  This is highly relevant for athletes to perform at their best in both shorter high-intensity training sessions (like smashing your virtual personal record, or VPR – check that out here.), or during racing.

Hope this helps understand a little of the science, and how to optimize your performances and well-being.

Thanks for reading – Go Longer.  Team SFuels.