Sugar Based vs Sugar Free Energy Gels: Which Works Better for Endurance?

If you've ever bonked at the 30k mark, or felt your stomach turn somewhere around halfway, you already know the gel question matters. Most endurance athletes have a story about a gel that worked beautifully in training and then sat heavy on race day. Or one that gave them a quick lift followed by a nasty crash twenty minutes later.

The energy gel market in Australia has split into two camps. Sugar based gels, which have been around for decades and dominate most race aid stations. And a newer wave of sugar free gels built around slow release carbohydrates. Both work. But they work differently, and they suit different athletes and different sessions.

Here's what the science actually says, what Australian athletes report, and how to choose what fits your gut and your goal.

How sugar based energy gels work

The classic energy gel formula is a concentrated mix of simple sugars, usually glucose plus fructose in a 2:1 ratio. The reasoning is sound. Glucose gets absorbed via the SGLT1 pathway in your gut, fructose through GLUT5. By using both, manufacturers can push more carbs through your system per hour than glucose alone allows.

For a short, hard effort this works well. You take a gel, your blood sugar rises within ten to fifteen minutes, and you get a quick energy boost. For a 10k or a sprint distance triathlon, that's often all you need.

The problem starts on longer days.

Concentrated sugar gels sit in your stomach as a thick syrup. Your gut has to dilute them before absorption, which is why most brands tell you to chase a gel with water. If you're already dehydrated, or if the effort has shunted blood away from your digestive system, that dilution doesn't happen efficiently. The result is the bloating, nausea and worse that something like 30 to 50 percent of endurance athletes report experiencing at some point.

The second issue is the spike and crash. A fast rise in blood sugar triggers a fast insulin response. Twenty to thirty minutes after the gel, you can find yourself lower than where you started, which is why race nutrition advice usually involves taking another gel before the first one wears off. You're chasing the curve instead of riding it.

Brands like Maurten, SIS, GU and PowerBar all use variations of this approach. Some, like Maurten, encapsulate the sugar in a hydrogel to slow stomach absorption. It's a smart innovation that helps with GI tolerance, but the underlying fuel source is still glucose and fructose, with the same spike and crash dynamic.

How sugar free, slow release gels work

The alternative approach, which UCAN built its product line around, swaps simple sugars for a slow release smart carbohydrate called LIVSTEADY. Instead of dumping glucose into your bloodstream all at once, LIVSTEADY releases steadily over 60 to 90 minutes.

The practical difference is significant. One gel covers a longer window. You don't get the spike, so you don't get the crash. And because there's no concentrated sugar load, your stomach handles it more easily, even when you're running hard or hot.

This is the formula UCAN Edge is built on. Same technology that's used by Olympic marathoners like Sara Hall and Meb Keflezighi, and by Ironman athletes who can't afford to gamble on their gut at km 35 of the marathon leg.

The trade off is honest. If you need a fast burst of energy for a final sprint finish, a sugar gel will hit faster. LIVSTEADY isn't designed for that. It's designed for steady, sustained fuel across hours, not minutes.

Side by side comparison

Which one should you choose?

It depends on what you're training for, how your gut responds under stress, and what kind of athlete you are. Here's how the choice usually breaks down.

Sugar based gels work best when

• You're racing under 90 minutes and need rapid fuel
• You need a quick lift for the final push of a race
• You've trained your gut to handle concentrated glucose and fructose
• You prefer the candy like flavour profile

Sugar free, slow release gels work best when

• You've experienced GI distress with traditional gels
• You're training for a marathon, an ultra or an Ironman
• You hate the crash that follows sugar gels
• You want a gel that fits into daily training, not just race day
• You fuel multiple sessions per week and want consistency
• You train in Australian summer heat where GI issues get worse

Many athletes use both

The best fuelers we know aren't loyal to one camp. They use sugar free gels for long training blocks and the bulk of a race, and keep a sugar gel in their kit for the final kilometres when they need a quick lift. It's a strategy that works particularly well for Ironman athletes managing the marathon leg, where a steady fuel approach for the first 30k and a sugar gel for the final push covers both needs.

What Australian endurance athletes are switching to

Talk to any running coach in Sydney or Melbourne and you'll hear the same shift. Athletes who spent years on traditional gels are moving to sugar free options, particularly for longer events. The reasons are usually personal. A bad GI day at an A race. The realisation that the post long run sugar crash was wrecking the rest of their day. The discovery that they'd been masking poor metabolic conditioning with sugar all along.

UCAN's adoption among elite Australian and international endurance athletes reflects this. Meb Keflezighi, four time US Olympian and Boston Marathon champion, fuels with UCAN. So does Sara Hall, American marathon record holder. Closer to home, Ironman athletes across the Gold Coast and Cairns are increasingly building UCAN into their long course nutrition.

If you're curious whether the switch makes sense for you, the easiest way to test is with a sample. Single serve sachets let you try Edge on a long run before committing to a full box.

Frequently asked questions