Jeukendup has served as an immense figure in affecting the guidelines surrounding carbohydrate consumption for endurance athletes. Interested in exercise science, sports science, and physiology due to his background as a professional athlete. he served many roles.
It was as the Director of Human Performance Laboratory and Research at University of Birmingham where he dove into how to change and optimize the guidelines of nutrition. These developments are what impacted his work with elite athletes and his investment into the brand NeverSecond.
Carbohydrates and Exercise: Where We Stand
- 1-2hr, 30g/hr
- 2-3hr, 60g/hr
- 3hr+, 90g/hr
How did we come to this protocol/recommendation?
- Blood glucose decreases with time as we exercise, without the addition of energy substrates.
- With carbohydrate (CHO) feeding, we know it helps us maintain blood glucose levels necessary for endurance performance. Studies had shown improved performance in cycling TTs (1min faster vs placebo). Additionally, they performed studies where a CHO solution was just swished and not even swallowed; still, a 1min improvement in TT performance.
- Mouth has receptors that “engage” the central effect on the brain to expect fuel coming on board as support, and delays it’s desire to slow your effort down.
- We store CHO in the muscle, liver (small amount). and we can deliver it (ingesting).
- Thus, we know that if you take CHO during exercise, and you can increase the amount your can deliver, your performance will improve.
So how do we deliver CHO effectively?
- Brief CHO lesson: Glucose, Galactose, and Fructose are monosaccharides (simple/single)
- Roughly 60g/hr was expected to be the upper limit of CHO oxidation (utilization). However, theoretically we know we should be able to utilize WAY more.
- Absorption: transporters are used to move glucose (though GLUT4) into the cell. However, when one targeted transporter gets saturated then that door becomes blocked up. Heres the catch: we have another door (GLUT5). This moves fructose into the cell independently of glucose.
- Combining glucose + fructose unlocks more doors, allowing us to increase total CHO ingestion significantly (75% in lab setting). This also showed roughly a %17 improvement in performance in a 40k TT over standard sports drink(s).
Does this work outside the lab, can it be done?
- Chrissie Wellington took in ~775g during her ~9hr Ironman World Champs in ‘07.
- Ironman Hawaii ‘09: Winning times plotted with CHO intake correlated indirectly (more CHO was related to lower times)
Other benefits of this Glucose:Fructose protocol:
- Delays onset of fatigue
- Improves performance
- Improve gastric emptying
- Increases fluid delivery
- Their products are designed to be combined with one-another without impairing CHO delivery. So, they work together vs. becoming affected by other food/products in the gut.
- C30: their way of simplifying your strategy. Each product is based around one ‘O’ symbol which equals a 30g serving of CHO.
- Combine ‘O’s as needed across the products (drink mix, gel) to reach your goal.
- Example: two gels ‘OO’ + a drink mix ‘O’ = ‘OOO’ (or 90g of CHO)