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Is white sugar that much of a performance booster?

Following the recent publication of a scientific study conducted among cyclists, some media network have come to allege that sucrose (table sugar) is better than glucose (found namely in sports gels and drinks) to delay the onset of fatigue during endurance events. But be wary of such hasty conclusions! Table sugar is not always your best option. Actually, in several cases, the latter is not even more beneficial than glucose.

First, glucose is one of the simplest types of carbohydrates that exists. It constitutes, among others, the basic molecule of starch and is also part of the chemical composition of several types of sugar, including sucrose. Indeed, sucrose is made in equal measure from glucose and fructose. When found in its most basic form, glucose is a type of sugar that is easily absorbed by the digestive system. Its maximum absorption rate is approximately 1 g/min, or 60 g/h. Subjecting your body to levels that go beyond this threshold may cause you to experience gastrointestinal discomfort as any excess glucose will not be assimilated by the body. In order to reach carbohydrate intakes that exceed 60 g/h, various sources of carbohydrates are required. Studies carried out over recent years have shown that ingestion of products providing multiple transportable carbohydrates allows increasing the rate at which carbohydrates are absorbed beyond 1 g/min. It is at this level that the addition of fructose really becomes beneficial. Indeed, it is being absorbed differently than glucose is, which allows the body to assimilate carbohydrates at a rate exceeding 1.5 g/min while minimizing gastrointestinal discomfort.

 

What are the recommendations?

 

The American College of Sports Medicine (ACSM) recommends 30 to 60 g of carbohydrates per hour as an optimal intake over the course of an endurance event. For instance, an energy gel will deliver between 20 and 30 g of carbohydrates. Several studies support this recommendation with the same conclusion that a 30-60 g intake is appropriate in endurance events that last from one to two and a half hours. How about ultra-endurance events? Is a 60 g carbohydrate intake per hour sufficient to support high performance over five to six hours? Probably not! Actually, when an event goes beyond three hours, it seems that ACSM recommendations are no longer adequate to maintain such level of performance. This is namely what Burke and coll. are questioning by rather proposing a targeted carbohydrate intake of 90 g/h for this type of event. A recent case study carried out with three elite, ultra-marathon runners notably showed that their average carbohydrate intake during a 100-mile (162-km) event reached 71 g/h.

 

 

What about table sugar then?

 

If you are participating in an endurance event less than three hours long, the choice of any glucose or sucrose intake will not make much of a difference in how you perform. Indeed, you won’t reach the physiological limit imposed by your body in terms of glucose absorption (60 g/h). So whether you choose sucrose over glucose will not allow you to draw any additional benefits. However, the intake of only one type of carbohydrates, such as glucose, won’t be sufficient for athletes who wish to reach high levels of performance during ultra-endurance events. At this level, the absorption capacity of the body constitutes a limiting factor, which can lead to a lower carbohydrate utilization rate. It is thus essential to use products providing multiple transportable carbohydrates if you wish to optimize the absorption capacities of your digestive system. That’s when the intake of several types of carbohydrates becomes extremely beneficial.

However, table sugar is not perfect though! First and foremost, it is recommended to saturate your body with glucose prior to adding some fructose. Consequently, the ideal glucose to fructose ratio would be around 2:1. The ratio for table sugar for its part is 1:1. There is thus no need to turn all of your current eating habits around. Most energy gels available on the market are designed for an optimal balance between the various types of carbohydrates in order to promote better assimilation. However, table sugar can seem like an easy and cheap way to fill up on carbs. Also keep in mind that you need to get started slowly when it comes to finding the appropriate recipe. And now, beyond these theories based on studies that involve individuals who are used to performing on a rich carbohydrate diet, what about people who are used to performing on a low-carb diet? The answer in yet another blog article.  :)

 

The Running Clinic's

Nutritionist