Not All Sugars Are Created Equal
We’ve all been there, thinking, this sandwich should cover me for the next 5 hours on my bike. 3 hours later you’re sat outside a cafe shivering on a hot day wondering where it all went wrong. This article should help you better understand a vital fuel source of cycling and how your body processes it.
Types of sugars
There are two main types of sugars: simple sugars and complex sugars. Simple sugars, also known as monosaccharides, are quickly broken down by the body and absorbed into the bloodstream. They include glucose, fructose, and galactose. Complex sugars, also known as disaccharides and polysaccharides, take longer to break down and are absorbed more slowly by the body. They include lactose, sucrose, and starch.
Glucose is the most important sugar for energy production in the body. It is the primary source of fuel for the brain and muscles during exercise. Fructose and galactose can also be converted to glucose in the liver for energy production.
When simple sugars are consumed, they are quickly broken down and absorbed into the bloodstream. This causes a rapid increase in blood sugar levels, which triggers the release of insulin from the pancreas. Insulin helps to move glucose from the bloodstream into cells for energy production or storage. Complex sugars take longer to break down and are absorbed more slowly into the bloodstream, causing a more gradual increase in blood sugar levels.
The Big 3: Fructose, Glucose and Maltodextrin
Fructose, glucose, and maltodextrin are all types of carbohydrates that can be used as energy sources during exercise. However, they differ in their chemical structure, how quickly they are absorbed, and how they are metabolized by the body.
Fructose is a simple sugar that is found naturally in fruits, vegetables, and honey. It is absorbed more slowly than glucose and is metabolized primarily in the liver. While fructose can be used as an energy source during exercise, it may not be as effective as glucose because it is metabolized more slowly and is not as readily available to working muscles (1).
Glucose is a simple sugar that is the primary source of energy for the body. It is found in many foods, including fruits, vegetables, grains, and dairy products. Glucose is absorbed quickly into the bloodstream and is metabolized by the muscles for energy. It is an important energy source during exercise, particularly during high-intensity activities (1).
Maltodextrin is a complex carbohydrate that is made up of chains of glucose molecules. It is derived from starch and is commonly used as an ingredient in sports drinks and energy gels. Maltodextrin is rapidly absorbed into the bloodstream and is metabolized by the muscles for energy. It is a popular carbohydrate source for cyclists and endurance athletes because it provides a sustained release of energy without causing gastrointestinal distress (2).
Fructose, glucose, and maltodextrin all have different characteristics and can be used as energy sources during exercise. Sports fuels such as mix and gels usually have a combination of these sources to provide the optimum absorption for your body.
What’s in my mix?
Most sports fuels use a combination of maltodextrin and fructose, rather than glucose alone, because this combination has been shown to optimize the absorption and utilization of carbohydrates during exercise.
Glucose is a simple sugar that is rapidly absorbed into the bloodstream and used for energy, but the rate of absorption can be limited by the availability of transport proteins that carry glucose across the intestinal wall. Fructose, on the other hand, is transported more slowly than glucose and is not as readily absorbed by the body, which means that too much fructose at once may not be fully absorbed and utilized for energy production.
Maltodextrin, on the other hand, is a complex carbohydrate that is more easily digested and absorbed than other complex carbohydrates like starch. It is rapidly absorbed into the bloodstream, providing a quick source of energy, and is tasteless, making it easy to use in sports fuels.
Combining maltodextrin and fructose in a 2:1 or 1:0.8 ratio has been shown to optimize the absorption and utilization of carbohydrates during exercise. Maltodextrin provides a quick source of energy, while the addition of fructose helps to increase the overall amount of carbohydrates that can be absorbed and utilized by the muscles. This combination has been shown to provide sustained energy during prolonged exercise, while also reducing gastrointestinal distress compared to other carbohydrate combinations.
Overall, the combination of maltodextrin and fructose has become popular in sports fuels because it has been shown to optimize the absorption and utilization of carbohydrates during exercise, providing athletes with a sustained source of energy and reducing gastrointestinal distress.
2:1 or 1:08, which is best?
Recent research has indeed suggested that a 1:0.8 maltodextrin to fructose ratio may be more effective than other carbohydrate ratios for athletes, particularly endurance athletes.
The reason for this is related to the way that carbohydrates are absorbed and metabolized by the body during exercise. When carbohydrates are consumed, they are broken down into their component sugars, such as glucose and fructose, which are then absorbed into the bloodstream and transported to the muscles for energy production.
However, the rate at which carbohydrates are absorbed can be limited by the transport proteins that carry them across the intestinal wall. Fructose, in particular, is transported more slowly than glucose due to the limited availability of transport proteins. This means that if too much fructose is consumed at once, it may not be fully absorbed and utilized by the muscles for energy production.
By combining maltodextrin with fructose in a 1:0.8 ratio, recent research has shown that the absorption and utilization of carbohydrates can be optimized during exercise (3). Maltodextrin is rapidly absorbed and metabolized, providing a quick source of energy, while the addition of fructose helps to increase the overall amount of carbohydrates that can be absorbed and utilized by the muscles.
In addition, the 1:0.8 maltodextrin to fructose ratio has been shown to reduce gastrointestinal distress compared to other carbohydrate ratios, which can be particularly important for athletes during long-duration events (4).
Like our holidays, this has got to be tailored to you
Ultimately, the most important thing to note here is that individual tolerance and preference for different carbohydrate ratios can vary. You should experiment with different ratios during training to determine what works best for you as some people tolerate different sources of carbohydrates more effectively.
This also goes for the quantity of carbohydrates that one can stomach while exercising. You hear of friends and teammates with stomachs of steel that can hold down just about anything, but that might not work for you and if you have gastric distress then that nutrition plan hasn’t worked for you. 2:1 ratios may be fine for some however a ratio of 1:0.8 maltodextrin to fructose may be more effective than other carbohydrate ratios for athletes with more sensitive stomachs.
Getting your fueling strategy right is key for the enjoyment of social, training, or competitive rides. Now go and find another reason why you have to go into that cafe.
References:
Jeukendrup, A. E. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), 25-33.
Jentjens, R. L., & Jeukendrup, A. E. (2005). High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. British Journal of Nutrition, 93(4), 485-492.
Wallis, G. A., Rowlands, D. S., Shaw, C., Jentjens, R. L., & Jeukendrup, A. E. (2005). Oxidation of combined ingestion of maltodextrins and fructose during exercise. Medicine and Science in Sports and Exercise, 37(3), 426-432.
Baur, D. A., Schroer, A. B., Luden, N. D., Womack, C. J., Smyth, S. A., & Saunders, M. J. (2018). Glucose-fructose ingestion and exercise performance: the gastrointestinal tract and beyond. Journal of sport and health science, 7(1), 1-9.
Disclaimer: I am not endorsed by any products here nor is this professional health advice. If you currrently have gastro issues, you may want to see a professional dietitian.
