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The combination of maltodextrin and fructose is key to SiS Beta Fuel, which is leading a revolution in endurance fuelling. This combination allows enhanced carbohydrate delivery and utilisation during exercise, whilst minimising gastrointestinal issues.

In the first study of its kind, we tested feeding athletes 120g of Science in Sport Beta Fuel per hour, singularly, and combined across our patented range of gels, chews and drinks. The previously recommended intake for endurance fuelling was 90g per hour.

  • Even after 3 hours of sustained effort 50% of energy used was from SiS Beta Fuel, rather than the body’s own fuel stores, with no cross-over from carbohydrate to fat usage taking place
  • The 120g carbohydrate intake can be achieved from our drink, gel or jelly chew, or any combination of the three
  • Athletes were using 1.5gm of carbohydrate per minute, the highest rates of carbohydrate oxidation ever reported, and had no stomach upset
  • They were able to sustain high performance intensity, with lower perceived effort

For training and competition of 2 – 2.5 hours or more, the SiS Beta Fuel range is the next generation of endurance fuelling and provides a variety of performance solutions to choose from with powders, gels and chews available to build your ultimate nutrition strategy. Our new formula uses an optimised ratio of maltodextrin to fructose providing a science-based complete fuelling solution for triathletes.

By using a precise balance of maltodextrin and fructose, rather than a single form of carbohydrate, performance improved with Science in Sport Beta Fuel, whilst avoiding any digestion issues. This new range uses a ratio of maltodextrin to fructose at 1:0.8 (previous 2:1) has been proven to:

  1. Enhance total exogenous carbohydrate oxidation by 17%
  2. Enhance mean power output during 10 maximal sprint efforts by 3%
  3. Increase the percentage of ingested carbohydrate oxidised from 62% (2:1 ratio) to 74% (1:0.8 ratio)
  4. Reduce symptoms of stomach fullness and nausea when compared to the 2:1 ratio

In summary, the all-new SiS Beta Fuel range works by providing these two different forms of carbohydrate which can be simultaneously absorbed. This is key as the transportation of nutrients across the intestinal wall, which is a rate-limiting factor in carbohydrate oxidation during exercise.


Swimming, cycling and running in multiple distances to choose from. Triathlon can be a complex sport alone without considering its fourth discipline – nutrition.
If you eat a balanced diet, your body can only store enough carbohydrate for around 90-120 minutes of exercise. Standard (Olympic), middle (70.3) and full (140.6) distance triathlons will all take over this amount of time.

That means for all of these distances you need to consider your fuelling strategy. Before the event it might be worth considering carbohydrate loading strategies (purposely consuming more carbohydrate in the days running up to an event), but importantly you need to consider your carbohydrate consumption during exercise, both what you will be consuming and when.

It is suggested that during endurance exercise (more than 2.5 hours) 80–120 g of carbohydrate per hour should be consumed to maintain blood glucose levels and prevent fatigue.

If you’re not used to consuming this much carbohydrate during exercise it is a good idea to test it out to ensure the body is capable. You may have to build up the amount of carbohydrate gradually, as you would when building up your training.


The new enhanced SiS Beta Fuel formula allows you to increase your carbohydrate intake to around 80-120 g per hour, as a result of the 1:0.8 maltodextrin and fructose ratio, aiding your performance by minimising gastrointestinal distress and enabling faster absorption.

The combination of two different forms of carbohydrates, maltodextrin and fructose in SiS Beta Fuel is key, in running specifically using a combination of different carbohydrates in comparison to a single form of carbohydrates has been shown to improve running performance.

Importantly, as mentioned above the 1:0.8 ratio has been shown to reduce symptoms of stomach fullness and nausea when compared to the 2:1 ratio which is great when considering the gastrointestinal issues often reported during the run of a triathlon.

But how is best to take on nutrition during a triathlon? Well, the perk of triathlon is the three disciplines, and you can adapt your nutrition for each discipline.


During the swim, most will choose not to fuel for obvious reasons (no one’s nutrition tastes nice soggy!), but it is still doable. You can either take a gel just before starting the triathlon or, although most don’t, if you feel you need to consume nutrition during the swim, you can store an SiS Beta Fuel Gel down the sleeve of your wetsuit. You will have to stop and tread water to consume it, but it is an option if necessary.


The bike discipline is arguably the best opportunity to consume nutrition during a triathlon. Your bike allows you to carry your nutrition easily. It’s important to start fuelling before you start to feel fatigued, it’s common to start fuelling within the first 10 minutes of being on the bike.

Bike boxes/bags on the top tubes or pockets in trisuits are great places to store SiS Beta Fuel Gels and Chew Bars, giving you varied textures to consume. You can also store 2-3 bottles on your bike (depending on model and size) that can contain SiS Beta Fuel 80 Powder in a flavour of your choice. The powder also contains sodium which will aid with hydration throughout the triathlon.


You’ve made it to the run. Fuelling for running is a common challenge and is individual between athletes. Some can continue their nutrition strategies into their run, whilst other athletes (particularly during a standard distance triathlon) will have focused on consuming all their nutrition during the bike segment of the triathlon.

For those who want to consume gels, the SiS Beta Fuel Gel with Nootropics is a powerful addition for the last push to the finish. Nootropics are substances that can enhance cognitive performance giving you that mental lift you might need, especially at the latter phases of exercise.


During a standard distance triathlon taking approximately 2 hours and 30 minutes with the aim of consuming 80–120 g of carbohydrate per hour (200-300 grams in total), you could use the SiS Beta Fuel range in the following format:

Swim 1500m – 1 x SiS Beta Fuel Gel in Strawberry & Lime before getting in the water – 40 grams
Bike – 40km – 1 x 500ml bottle with SiS Beta Fuel Powder in Red Berry flavour – 80 grams
2 x SiS Beta Fuel Chew Bars, one of each of the Lemon and Orange flavours – 80 grams (40 g per bar – 7 g per chew)
Run -10km – 1 x SiS Beta Fuel Gel with Nootropics in Lemon & Lime flavour – 40 grams

This would give a total of 240 grams of carbohydrate over the standard distance triathlon. This provides a varied nutrition solution in different formats, flavours and textures whilst maintaining the quality of your nutrition so you can train or race at the best of your ability.

Practice makes perfect when it comes to nutrition strategies for triathlon. Use your training sessions to simulate race intensities and consuming fuel. Individual requirements will vary depending on body weight and it may take time to adapt to consuming this amount of carbohydrate.

We recommend you practice your nutrition during training to find the optimal amount that works for you.

For more information about the Science in Sport Beta Fuel range, visit here.


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O’Brien, W. J., & Rowlands, D. S. (2011). Fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance. American Journal of Physiology-Gastrointestinal and Liver Physiology, 300(1), G181-G189.

Rowlands, D. S., & Houltham, S. D. (2017). Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance. Medicine and science in sports and exercise, 49(8), 1734-1744.

Wallis, G.A., Rowlands, D.S., Shaw, C., Jentjens, R.L., Jeukendrup, A.E. (2005). Oxidation of combined ingestion of maltodextrins and fructose during exercise. Medicine & Science in Sports & Exercise. Mar;37(3):426-32.

Written By

Dr Emily Jevons - PhD in Exercise Physiology & Nutrition, Clean Sport Advisor

Emily has worked with Science in Sport since 2021. With a PhD in Exercise Physiology & Nutrition, she currently provides nutritional advice for endurance athletes. Emily not only understands the science behind performance nutrition solutions, but also the physiological and psychological demands of sport after competing competitively in swimming and triathlon for a number of years.