Sports People & Athletes

Fuel management is key
Those people training and competing for their best performance know about the relevance of nutrition and fuel management. Using the body’s fuel resources most efficiently is important to perform best and win the race.

Carbohydrate and fat fuel are the main energy sources, their interplay is important: Where an athlete engages in intense exercise, his body burns carbohydrates with preference because of their faster energy flux. His carbohydrate resources in form of glycogen in muscles and the liver are limited, though, and their depletion and subsequent drop in blood sugar levels will lead to his exhaustion. In case the exercise lasts longer, his body is keen to use fat fuel alongside. Energy resources from fat are essentially unlimited, and hence using fat fuel alongside helps the athlete to spare carbohydrate resources.

Optimizing fuel resources for endurance
Athletes have developed several strategies to manage their fuel resources and sustain carbohydrate energy for longer endurance: Firstly, regular endurance training helps them to increase the muscles’ capacity for fat utilization. During the days before an event, carbohydrate loading regimens are applied to fill glycogen stores to the maximum. Taking sports drinks and pouches before and during the event supplies additional carb fuel and delays carb depletion. And finally after the event or a strenuous exercise, a fast refill of glycogen stores supports their recovery for the next exercise.

Figure 1: Athletes’ strategies to optimise their fuel resources for endurance.

A wide range of sports nutrition products are available in the market for the different purposes. While a large number of those contains fast carbohydrates (as such or in blends with a 2:1 ratio of glucose and fructose), there are many occasions where the steady and sustained energy supply from isomaltulose can have advantages. One example is the use of sports drinks before and during sports:

Figure 2: Most common carbohydrates in sports nutrition are “fast carbs”. The novel carb isomaltulose offers new opportunities for energy management during sports.

Why choosing a sport drinks with isomaltulose
It is beyond doubt that additional carbohydrate intake before and during exercise can extend endurance performance (Thomas et al 2016). Both “high GI” and “low GI” carbohydrates have shown effective in this respect (see e.g. Earnest et al in 2004), while choosing low GI carbohydrate before and during exercise has the advantage to maintain fat oxidation rates (Earnest et al 2004; Achten et al 2007). The aim to increase fat oxidation rates for the purpose of glycogen sparing and endurance performance is not new (see e.g. Jeukendrup et al 1998). However, its implementation in practice was difficult for long because of the limited availability of suitable carbohydrates – delivering full carbohydrate energy and maintaining higher fat oxidation rates at the same time. Such a carbohydrate has become available with isomaltulose.

Sport drinks with isomaltulose – for steady and sustained energy
Isomaltulose has shown to provide carbohydrate energy in a steady and sustained energy, and thereby allows for higher fat burning rates in energy metabolism. Its influence on fuel use and endurance performance has been tested and confirmed in a series of studies with trained endurance athletes and physically active men. Isomaltulose was consumed before and during physical activity of different intensity levels. In all of these studies, the consumption of isomaltulose – instead of conventional high glycemic carbohydrates such as maltodextrin or sucrose – before and during physical activity was linked with a higher contribution of fat oxidation in energy metabolism (König et al 2007, König et al 2016). Isomaltulose was tolerated well, even when consumed in high amounts common in sports (e.g. up to 125 g), and it has shown to give sufficient carbohydrate energy for endurance exercise at high intensity levels.

Figure 3. The advantage of higher fat burning with isomaltulose in fuel management and endurance (König et al 2016).


Whether the improved energy supply from isomaltulose –  its steady energy release and higher fat burning – would result in advantages for endurance performance was specifically addressed in the study of König et al (2016). In this randomized controlled trial, the 20 endurance athletes showed more stable and sustained blood glucose profiles and higher fat oxidation rates during the 60 minutes endurance exercise after consuming isomaltulose in comparison with maltodextrin. In a subsequent time trial, the athletes tended to perform better after isomaltulose intake, finishing the time trial about 1 minute faster and with a higher power output.

While research findings are assuring, it is even more relevant that it works to the needs of an athletes. Many athletes and sports people have  tried and discovered advantages of isomaltulose in their training and competition. One example is the story of Stefan Schlegel, who mastered the RAAM with isomaltulose.

A Personal Success Story – the RAAM
Stefan Schlegel, a German cyclist participating in The Race Across America (RAAM), one of the toughest cycling races in the world, completed his training and the race itself on a nutrition plan including isomaltulose as the principle carbohydrate consumed with sport drinks and soups. His consumption of isomaltulose amounted to approximately 800 g/day and represented 53-59% of the total carbohydrate intake and about 32- 35% of the total energy intake. Competing with isomaltulose, rather than on a combination of fast carbohydrates, might seem “crazy” to others. However, Stefan finish the race in 10th place of 42 solo racers. When asked about his experience with isomaltulose, he said that he experienced no hunger pangs during the complete race. He further went on to say:

“Especially during heavy training periods, isomaltulose helped to keep my energy level constant – which is crucial for endurance races such as the RAAM.”


Endurance training with isomaltulose
When athletes conduct long units of endurance training, they commonly avoid the intake of “fast carbs”. Isomaltulose can serve as alternative because it does not suppress fat oxidation like fast carbohydrates do. “Isomaltulose is a big help during these long endurance rides to train maximize the fat oxidation.” (Matthias Knossalla, Profi Triathlete)

Carbohydrate loading with isomaltulose
The carb loading procedure before an event commonly starts with an initial glycogen-depleting exercise that is followed by three to four days of re-filling with super compensation. During those days, athletes reduce their training and consume daily 10-12 g carbohydrate per kilogram body weight. For a man of 70 kg, this means an intake of 700 g respective 2800 kcal or more of carbs only. Athletes report that the more steady glucose supply from isomaltulose helps them to feel better and be more focused during this phase. The triathletes Marc Rink and Matthias Knossalla described this as follows: “You need drinks to get the 700g of carbohydrates. Years ago we tried with cola, lemonade, high GI carb drinks, but you feel dizzy, you feel lazy, your blood sugar level goes up and down. And this is not how you want to feel 48 hours before the main competition of the year… We tried isomaltulose because of the stable blood sugar levels and it helped us a lot.”

Recovery and bed time drink with isomaltulose
When training sessions last into late evening hours, a fast recovery and speedy refueling of glycogen stores is needed to be prepared for the next morning session. Besides a recovery drink after exercise, and a late evening meal, many athletes take a bed time drink before sleeping. However, taking “fast carbs” with the bed time drink can pose a challenge to a night’s recovery sleep. Using isomaltulose instead for its steady and sustained energy supply can have advantages. The triathlete Matthias Knossalla described:  “When you finish the last training session at 10 pm and start the next day session at 7 or 8 am, it really is a problem to regenerate overnight. I woke up in the night feeling empty, and I needed some calories or I woke up the next morning still felling exhausted. Now I use isomaltulose for recovery during the night in combination with some protein and I feel much fresher the next morning ”


Achten J, Jentjens RL, Brouns F, Jeukendrup AE (20017) Exogenous oxidation of isomaltulose is lower than that of sucrose during exercise in men. J Nutr 137(5):1143-8. Link:

Earnest CP, Lancaster SL, Rasmussen CJ, Kerksick CM, Lucia A, Greenwood MC, Almada AL, Cowan PA, Kreider RB (2004) Low vs high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. J Strength Cond Res 18(3):466-72. Link:

Jeukendrup AE, Saris WH, Wagenmakers AJ (1998) Fat metabolism during exercise: a review. Part I: fatty acid mobilization and muscle metabolism. Int J Sports Med 19(4):231-44. DOI: 10.1055/s-2007-971911

König D, Zdzieblik D, Holz A, Theis S, Gollhofer A (2016) Substrate Utilization and Cycling Performance Following Palatinose™ Ingestion: A Randomized, Double-Blind, Controlled Trial. Nutrients 8(7):390.

König D, Luther W, Polland V, Berg A (2007) Carbohydrates in sports nutrition impact of the glycemic index. AgroFood Anno 18(No. 5):9–10.

Thomas DT, Erdman KA, Burke LM (2016) American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc 48(3):543-68. doi: 10.1249/MSS.0000000000000852