While carbohydrates are still often misunderstood by the general public, serious athletes know they are crucial. Without carbohydrates for fuel, performance will suffer.
Marketing companies know this too, which is why there are now hundreds of endurance fueling products. Which leads us to the question: What is the best fuel?
Let’s sift through all the marketing ploys and focus on the science of what really makes an optimal fuel.
1. Must Contain Glucose and Fructose
For a very long time, endurance athletes consumed only glucose as their fuel. Glucose is a simple sugar, so it is readily absorbed by the body so it can be used quickly for energy.
The problem is that the body’s carbohydrate transporters can only absorb a limited amount of glucose per hour. For most people, this amount is around 60 grams per hour. If you consume higher amounts of glucose, it may not be absorbed. Even worse, it can stay in the gut and cause digestive issues.
Considering the very high energy demands of endurance athletes, 60 grams of glucose is not adequate.
However, the body uses separate transporters for fructose. By combining glucose and fructose, the body can absorb approximately 90 grams of carbohydrates per hour (and possibly more).
Surprisingly, a lot of fueling products still don’t contain fructose, even though the research is well-established. So, make sure you are choosing a fuel that has both of these carbohydrates.
2. Right Carbohydrate Ratio
It isn’t just the type of carbohydrates that matter when it comes to fuel: the amounts also matter.
Research shows that a 1:0.8 ratio of glucose to fructose provides the best results when it comes to absorption and avoiding gastrointestinal issues.
3. Maltodextrin as Glucose Source
Making sense of fuel nutrition labels can be confusing because there are many different forms of glucose.
For fuel, you want to choose a product that uses maltodextrin. Compared to other forms of glucose, maltodextrin has many benefits—including a lower osmolality and thus better absorption rate.
One of the other key benefits of maltodextrin is that it isn’t sweet. Fructose is very sweet, so fuel products that contain sweet forms of glucose can end up disgustingly sweet. The flavorless characteristic of maltodextrin means your fuel actually tastes good instead of making you want to gag after your 10th one in the final leg of a race.
Read more about maltodextrin here.
4. Electrolyte Formula to Match Needs
Most fuel products also contain electrolytes. This allows endurance athletes to take care of their fueling and hydration needs simultaneously.
However, electrolyte formulas are one of the areas where many fueling products get the science wrong. They typically contain very high amounts of magnesium based on the myth that it prevents cramps (there is no evidence that low magnesium causes cramps; cramps are typically due to inadequate fueling).
Instead, you should look for electrolyte formulas that match the salts lost in sweat.
If you are consuming electrolytes from another source, are not a “salty sweater”, or conditions are very cold, then you may not want much or any electrolytes in your fuel. So, pay attention to the amounts to see if they match up to your needs.
Learn more in our Hydration Guide.
5. Gel or Drink Form
For endurance athletes, the best fuel is a gel or drink. Neither is necessarily better than the other: it depends on personal preference, and most athletes will use a combination of both gels and drinks for fueling.
While some athletes do get some of their fuel from solids (such as fuel bars), solids can be hard to digest—especially during high-impact activities like running. These types of fuel are usually best left for low-to-mid intensity workouts.
6. No BS Ingredients
Here’s where things can get tricky: A lot of manufacturers add “magic” ingredients to their fuel formulas. On paper, these ingredients sound great—but often provide no actual value and may even cause digestive side effects.
Menthol is a good example of this. It was hyped up in the sports world for a while because it supposedly boosted performance. But the evidence shows that adding this to fuel provides no actual value.
So, which added ingredients actually are beneficial? Caffeine is one that has many proven benefits. Sodium bicarbonate is another. However, for these to be effective, they have to be used properly and in the right doses.
Follow the Science
Science is an ongoing process, and what is considered the optimal fuel today may change in the future. However, there is already ample research into sports fueling. And, while some results are inconclusive, we have knowledge that’s been proven both in the lab and in practice by top-level athletes.
At Nduranz, our goal is to follow the science. All of our products are based on the latest research, and not what happens to be trendy at the moment.
When it comes to science and quality, we never compromise.
Check out our fueling products here, or read our guide to learn more about the Science of Fueling.