Both Nuun Endurance and e-Fuel do an excellent job of hydrating without causing stomach issues. However, Nuun Endurance uses nearly 100% simple sugars compared to e-Fuel that uses complex carbohydrates. This is a big difference as complex carbs allow for increased energy uptake (discussed below). e-Fuel also uses a bit of fructose that further increases performance (read carb sources below). e-Fuel is all natural with NO artificial flavors, colors, sweeteners, sugar substitutes or stimulants – it’s just clean energy! If you truly want a drink for “endurance” purposes, e-Fuel has several advantages. Read on for the complete comparison:
calories (8 oz)
e-Fuel provides more than twice as much energy (calories) as Nuun Endurance, and we are able to do this through the use of complex carbs instead of the sugars used in Nuun.
If you plan on using Nuun and getting the rest calories from food (energy bars, fruit, etc.), this is a bad idea for several reasons.
Problem # 1 It all ends up in the same place
Once you start eating and drinking it all ends up in your stomach …. the Nuun, the banana, the PowerBar and what ever else you decide to eat. Guess what, the osmolality of the fluid in your stomach just went up and the absorption rate slowed or even came to a halt. Not a good thing.
Problem #2 Digestion
Most foods that you eat contain proteins, fats and/or fibers. Once one or more of these are introduced to your stomach they have to go through a digestive process. When you are doing aerobic activity the blood supply to your stomach gets shut down in order to maximize blood flow (and oxygen) to the working muscles for the oxidation process. More oxygen = increased performance (just ask Lance). Digestion of those foods you just ate requires blood flow back to the stomach and away from the working muscles … and that sound you just heard was your performance dropping.
Problem #3 Delayed Energy
We all know that bananas are one of the most common foods consumed by endurance athletes, but do you know how long it takes a banana to leave your stomach? Try 3 hours and 15 minutes! Eating solid foods during typical workouts or competitions might taste good and satisfy your craving for food, but it does little if anything for your performance.
Note about Ultra Endurance Athletes
If your an ultra athlete competing for 20+ hours the normal rules don’t apply to you. You are going at a slower pace so you can afford some blood to go back to the stomach to work on digestion. And if it takes 4+ hours for the banana to kick in that’s okay!
By far the biggest difference between e-Fuel and Nuun Hydration is that e-Fuel uses primarily complex carbohydrates and Nuun Endurance is virtually all simple sugar. This is critical because your body can uptake more energy when you use complex carbs instead of simple sugars.
This isn’t something we’ve invented, it’s proven science. If you’re interested in the details here’s how it works:
The carbs/energy in a sports drink are transported into your cellular system through osmosis. If you recall learning about osmosis in science class, it’s the way a fluid crosses a membrane. In order for the fluid to cross, it has to be an equal or lower concentration than the fluid on the other side of the membrane. In this case you’re trying to get the sports drink across your cellular membrane so you can use the energy. Ideally you want the drink to be isotonic, which means it’s the same concentration as your cellular fluids. At this point the drink can be rapidly absorbed and carry the carbs and electrolytes along with it via osmosis.
What’s interesting is that the concentration of a fluid (also called the osmolality) is largely dependent on the NUMBER of particles in the fluid, and less dependent on the size of the particles. Complex carbs by definition have a larger molecular structure than simple sugars, basically they have more glucose molecules stuck together. But remember, it’s the number of particles, not the size that matters most. What that means is that at the point of absorption (isotonic), a fluid with complex carbs can transport nearly twice as much energy into the cellular system compared to one with simple sugars.
Many drinks (including e-Fuel) use at least some maltodextrin for this reason. Maltodextrin is a complex carbohydrate with an extremely large molecular structure. Where e-Fuel sets itself apart from other products is that we use much more complex carb and less sugar. In the case of Nuun Endurance they use virtually all sugar. This allows you to get more energy when you use e-Fuel compared to our competitors. If you’re doing any type of endurance sport, then maximizing energy uptake should be important to you.
If you’re doing short workouts sugar can provide adequate fueling. But if you’re doing any kind of endurance event then you will perform better using complex carbohydrates instead of simple sugars. See our complex carb discussion for more details.
The cane sugar and dextrose in Nuun Endurance are both forms of simple sugars. Maltodextrin is a long chain complex carbohydrate. As we explained in the complex carb discussion, the advantages of complex carbs are significant.
Fructose is also a sugar, but it’s very different than all other forms of sugar and we use it in all of our products for a very good reason.
Fructose sometimes gets a bad rap for endurance athletes because it is thought to cause stomach and GI discomfort. Like anything else, if you take too much fructose it can be a problem. But if you use it properly it can actually significantly improve performance … without stomach issues. Here’s why:
Most of the energy that we use during endurance sports comes from consumed carbohydrates that are converted into glycogen and stored in our muscles. Glycogen can then be quickly broken down into glucose and used to fuel the muscles. The liver also stores glycogen which has been converted from fructose and serves as an additional “fuel tank” to power your muscles.
Here’s where it gets interesting …
The main route for glucose absorption from the gut is through a transporter called SGLT1 – a protein that acts like a door, helping glucose go from the gut to the bloodstream. SGLT1 has a maximum capacity and can only transport around one gram of glucose per minute (240 calories/hour). Fructose, however, is absorbed with a different transporter, called GLUT5. By using both transporters you can increase the amount of carbohydrate the body can use during exercise up to approximately 300 calories/hour.
GLUT5’s sole job in life is to transport fructose, so if you’re not consuming fructose then you’re not using the GLUT5 transporter … it’s like having an additional fuel line and not using it, why would you do that? In addition, your secondary fuel tank (your liver) will be under utilized as well.
The rapid absorption of fructose mixtures and special handling of fructose in the liver are the two main reasons that fructose can also also help to speed up recovery after exercise. A recent study found that when athletes drank sports drinks containing both fructose and complex carbohydrates after exercise, they accelerated the recovery of their liver glycogen stores. It almost doubled this rate of recovery compared with drinks that didn’t have fructose, when the same total amount of carbohydrate was consumed.
Bottom line … if you want to “be your best”, incorporate some fructose into your training and competition nutrition program.
In developing e-Fuel we relied heavily on the decades of independent research performed by the American College of Sports Medicine. They are a non-profit with no “skin in the game”, they just try to figure out how to make athletes better, stronger and faster. Electrolyte replacement is an area that they have studied extensively, and e-Fuel’s electrolyte levels are designed to meet their recommendations.
Potassium is the other electrolyte that is important to replace during your training and competition, along with sodium. The level of potassium in e-Fuel is designed to meet the American College of Sports Medicine’s recommendation for replacement during athletic activity.