Carbohydrate Innovations over the Decades
Published at 29 May 2019

Carbohydrate is the body’s 5-star fuel.

 

Assuming you have a healthy water intake and daily diet it can mean the difference between adequate and excellent endurance performance. We’ve taken a look at how  the understanding of carbohydrate nutrition has changed over the last few decades and what this means for athletes seeking maximum performance. 

The 1980's

Until the 1980’s, any nutritional advice available to athletes was pretty basic. Many endurance athletes believed high-protein meals such as steak and eggs were ideal pre-race nutrition. However, towards the end of the 80’s a small number of studies on endurance performance started to demonstrate the importance of carbohydrates in relation to endurance performance.

The 1990's

By the early 90’s the number of studies was increasing rapidly and a breakthrough in our understanding of the importance of carbohydrate nutrition had been made. The key finding at this time was that  consuming carbohydrate during exercise helps offset the effects of glycogen depletion by providing working muscles with another source of carbohydrate. As a result millions of endurance athletes in the 90’s found that by applying the above knowledge to their training they were able to go further and faster. They also began to understand the importance of pre-race fuelling with carbohydrate and post-race carbohydrate for recovery. 

The studies performed in the 90’s were mainly focussed on glucose drinks and while they produced significant performance improvements, these types of drinks are only able to provide around 60g per hour, which is a fairly modest replenishment for an athletes who can expend almost four times this amount during competition. Around this time drinks containing a combination of glucose and fructose started to be studied inn rode to see how well these were absorbed into the body during exercise and how they were oxidised for energy. The key finding across these studies were that when athletes who drank a 50/50 glucose/fructose mix he amount of ingested carbohydrate the they were able to use for energy production increased by over a fifth. The study, along with many others at this time, showed that glucose/fructose mixtures (so-called multiple transportable carbohydrates) do result in higher oxidation rates of ingested carbohydrates. This is because glucose and fructose are absorbed from the intestine by a different type of transporter. Subsequent studies of 2:1 glucose/fructose drinks showed results such as preserved muscle glycogen stores, better hydration due to increased blunts of water from the stomach, reduced perception of stomach fullness after consumption and lower perceived rates of exertion in latter stages of exercise. Even more importantly this research showed that  glucose/fructose combination does indeed translate to better performance. 

And now?

Putting together the early carbohydrate research of the 80’s and 90’s with the recent findings the following general recommendations can be made:

Exercise up to 30min - no necessary on-the-go supplementation, recovery drink when finished.

Exercise for 30-60 min - small amounts or mouth rinsing of carbohydrates, recovery drink.

Exercise for 1 to 2hours - 30g of carbohydrates per hour, hydration, recovery drink.

Exercise for 2 to 3 hours - 60g of carbohydrates per hour, hydration, recovery drink.

Exercise for 3 hours+ - 90g carbohydrates per hour, hydration, recovery drink.

Do we gel?

Why choose drinks over gels?

A key consideration with gels is that tolerance can vary widely from person to person. In a 2009 Peak Performance study 7 out of 9 triathletes reported gastrointestinal discomfort (tummy cramps, bloating etc.) when using gels. In contrast not one of the 9 reported any of these effects when using a carbohydrate drink. One possible explanation for this is that whereas carbohydrate drinks provide a constant concentration of carbohydrates when consumed, consuming gels plus water can result in different (and at times higher) carbohydrate concentrations, depending on the timing of water consumption. If you have a particularly sensitive tummy it is probably best to rely on pre-mixed carbohydrate drinks over gels. Also, at very high rates of carbohydrate intake (above 80g per hour) carbohydrate drinks are easier on the tummy regardless of whether you are sensitive to gels or not.

Carbohydrate drinks take all of the guess work out of water intake for you, when mixed as directed they will provide the correct ratio of carbohydrates to water for your chosen sport.

 

 

 

 

 
 
 
 
 



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