Energy range - Carbohydrates

As you may know, your body uses two main sources of fuel to create energy for you to be able to run, bike, swim, or do any other kind of sport: fat and carbohydrates (in the form of glucose). With higher intensities, your body is more reliant on carbohydrates, and the relative contribution of fat decreases. This is because carbs can be turned into energy faster compared to fat, and therefore are a more efficient fuel for your body. Thus, if you want to go fast, your body really needs those carbohydrates! 

There is one problem: only a limited amount of carbs (in the form of glucose) can be stored in the body. This glucose is stored as glycogen in the liver (100 g) and the muscles (350 – 700 g), and is enough for only 45 – 90 min of moderate to high intensity exercise. Depleted glycogen stores can be experienced as ‘hitting the wall’ – the feeling of not having any energy left, which is definitely something you want to avoid!

Carbohydrate ingestion during exercise

To make sure that sufficient carbs are available to be used as energy and subsequently maintain high intensity performance (going fast!), it is important to consume carbohydrates duringexercise. How much? This depends on the duration of exercise. The table below gives an overview of the recommended carbohydrate intake for different exercise durations (these recommendations are for well-trained athletes. Less trained athletes may need to adjust these recommended values downwards). Here you can for example see that there is no need to take any carbs when exercising for less than 30 min, the glycogen stores in your body should be sufficient. However, when exercise takes longer than an hour you do want to take in some carbs, and higher carbohydrate intakes are needed with increasing exercise durations (up to 90 g/h for exercise than lasts longer than 2.5 h). 

Carbohydrate absorption 

Then there is another problem: your body can only take up ~60 g/h of glucose. When ingesting more, this will simply not be absorbed and the glucose will accumulate in the intestine. In the end this may result in gastrointestinal problems (something you definitely want to avoid, right?). The good news is that there is a way to bypass this problem and to increase the total carb absorption: adding a different type of carbohydrate that is absorbed in a different way in your intestine. This means that the combined ingestion of different types of carbohydrates can result in increased intestinal carbohydrate absorption (up to ~90 g/h). Thereby glucose + fructose in the ratio of 2:1has been shown to be one of the best combinations. 

Upcoming - Vifit Sport Energy Range!

This autumn, the Vifit Sport Energy Range will be launched. The complete Vifit Sport energy range contain the carbohydrates glucose + fructose in the ratio of 2:1 (or come very close to this ratio) in order to maximize carb absorption and minimize gastrointestinal problems. In addition, the energy gels and bars all contain 30 g of carbs per serving. This makes your nutrition planning a whole lot easier: you can just take 1, 2, or 3 servings per hour, depending on the duration of your exercise (see table).

Next to carbohydrates, other nutrients can be really useful as well, such as sodium and caffeine. 


Carbohydrate intake during exercise is important to make sure that your muscles have enough energy to maintain endurance performance, especially when exercise durations are more prolonged. Thereby it is optimal to include a combination of different types of carbohydrates. The combination of glucose + fructose in a ratio of 2:1 has been shown to be very effective

Author: Job van Leeuwen, on behalf of Vifit Sport

1.            Van Loon LJC, Greenhaff PL, Constantin-Teodosiu D, Saris WHM, Wagenmakers AJM. The effects of increasing exercise intensity on muscle fuel utilisation in humans. J Physiol. 2001;536(1):295–304. 
2.            Gonzalez JT, Fuchs CJ, Betts JA, van Loon LJC. Glucose plus fructose ingestion for post‐exercise recovery—greater than the sum of its parts? Nutrients. 2017;9(4):1–15. 
3.            Jeukendrup A. A step towards personalized sports nutrition: Carbohydrate intake during exercise. Sport Med. 2014;44(SUPPL.1). 
4.            Trommelen J, Fuchs CJ, Beelen M, Lenaerts K, Jeukendrup AE, Cermak NM, et al. Fructose and sucrose intake increase exogenous carbohydrate oxidation during exercise. Nutrients. 2017;9(2):1–12. 
5.            Cermak NM, Van Loon LJC. The use of carbohydrates during exercise as an ergogenic aid. Sport Med. 2013;43(11):1139–55. 
6.            Shirreffs SM, Sawka MN. Fluid and electrolyte needs for training, competition, and recovery. J Sports Sci. 2011;29(SUPPL. 1):37–41. 
7.            Coyle EF. Fluid and fuel intake during exercise. J Sports Sci. 2004;22(1):39–55. 
8.            Stachenfeld NS. Sodium ingestion, thirst and drinking during endurance exercise. Sport Sci Exch. 2014;27(122):1–5. 
9.            Spriet LL. Exercise and Sport Performance with Low Doses of Caffeine. Sport Med. 2014;44(Suppl 2):S175–84. 
10.         Burke LM. Practical Issues in Evidence-Based Use of Performance Supplements: Supplement Interactions, Repeated Use and Individual Responses. Sport Med. 2017;47(s1):79–100. 
11.         Maughan RJ, Burke LM, Dvorak J, Larson-Meyer DE, Peeling P, Phillips SM, et al. IOC consensus statement: Dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–55.