1:0.8 – Carbohydrate ratio

1:0.8 – carbohydrate ratio – the ultimate performance formula in sports? 

It is undisputed that carbohydrate intake for performance is an essential component of sports nutrition. However, there is an important scientific fact in this context: sugar and carbohydrate sources are characterized by different metabolisms. On this basis, it has been shown that the "right" combination of different carbohydrate sources can significantly improve athletic performance. 

But let's go into a little more detail: 

About 20 years ago, scientists discovered that certain carbohydrate combinations can be absorbed (transport from the small intestine into the blood) at different rates. Up to that point, it was assumed that the maximum amount of carbohydrates that could be absorbed was about 60 grams per hour (or 240 kcal per hour). Given the sometimes high energy demand of over 1000 kcal/h in ultra-endurance sports, the goal was set to find out how the intake and utilization of carbohydrates can be increased. 

After years of meticulous research, it was discovered that neither gastric emptying or carbohydrate absorption in the muscles nor muscle metabolism are the limiting factors of utilization. Focus was therefore placed on the absorption of carbohydrate sources, leading to the following findings: 

• Carbohydrate intake is generally regulated by transport proteins.  

• Glucose (grape sugar) as a fast-acting sugar is transported by a sodium-dependent glucose transporter 1 (SGLT1). The saturation limit of the transport medium is 60 g of glucose per hour. 

• Fructose (fruit sugar) as a slow-acting sugar is transported by the GLUT5 protein. The saturation limit is 30 g of fructose per hour.  

• It was discovered that the simultaneous use of both transporters increases carbohydrate intake. Many studies showed that the combination of glucose and fructose increases oxidation rates (burning rates) by 50%! This opened up many possibilities: Different carbohydrate combinations could be tested, and the absorbed amounts were increased to up to 140 g/h.

• The highest oxidation rates with a simultaneously low residual volume of carbohydrates in the intestine were observed at an intake of approx. 100 g/h. The reason is as follows: ideally, when we consume 100 grams of carbohydrates, we want the highest possible utilization or virtually no residual volume in the intestine. The more carbohydrates remain in the stomach, the greater the likelihood of digestive problems. The highest oxidation efficiency was observed with the intake of 100 g/h as glucose and fructose in a 2:1 ratio. 

• Later, the carbohydrate ratio of 1:0.8 (glucose: fructose) was investigated, which on the one hand further increased the oxidation capacity and on the other hand significantly reduced potential digestive problems.

• The results of all these studies indicated that 60-90 grams per hour is a safe amount for intake, as only very few athletes showed gastrointestinal problems. 

What is the optimal ratio – 2:1 or 1:0.8 – and what conclusions can we draw from NO CARBS, NO GLORY!? 

• The "optimal ratio" changes depending on the amount of carbohydrates consumed. For now, we can conclude that intake must be individualized based on tolerance. This tolerance can be trained by training the gut ("train the gut"), but the intake should be based on what is easily tolerated. Especially at the elite level, higher intake amounts should be aimed for. It is the target intake that then determines the optimal ratio. 

• A distinction is made between fast and slow carbohydrate sources. Glucose and maltodextrin cause a sharp increase in blood sugar levels, which is expressed by the glycemic index (GI). These so-called "fast" sugars are digested, absorbed, stored in the muscles, and utilized more quickly. While both glucose and maltodextrin have a high glycemic index (the GI of glucose is 100 and that of maltodextrin is even higher, at about 105-185), fructose is a "slow" carbohydrate with a low GI of about 23. Fructose must be digested, absorbed, and then processed by the liver before it can be used by our muscles for energy production. 

• Maltodextrin as a component of sports products is a good choice. Simple sugars have a higher risk of causing gastrointestinal discomfort because intestinal bacteria feed on simple sugars, which can lead to bloating and a feeling of fullness. In contrast to longer-chain molecules like maltodextrin, simple sugars like glucose and fructose have a higher risk of stomach discomfort because they bind water and transport it with gastric emptying. 

• Strictly speaking, there is therefore no optimal ratio for carbohydrate combinations. However, reviewing all studies suggests that the carbohydrate matrix 1.0,8 – maltodextrin (glucose): fructose brings slight advantages regarding absorption rate, oxidation (burning), and the avoidance of digestive problems. That is why this ratio of 1.0,8 is the basis of NCNG sports products. 

Table 1: Recommended basic carbohydrate intake / training duration in g/hour (more at high intensity) 

Literature: 

Jeukendrup, A. E. (2011). Nutrition in endurance sports: Marathon, triathlon and road cycling. Food, Nutrition and Sports Performance III, 29, 91-99. 

O’Brien, W. J., Stannard, S. R., Clarke, J. A., & Rowlands, D. S. (2013). Fructose-maltodextrin ratio controls exogenous and other CHO oxidation and performance. Medicine and Science in Sports and Exercise, 45(9), 1814-1824. 

Stellingwerff, T., & Cox, G. R. (2014). Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations. Applied Physiology, Nutrition and Metabolism, 39(9), 9