Glucose vs. fructose in energy gels and drinks – why a "one-size-fits-all" ratio doesn't work

 

1. Why the classic mixing ratio can be problematic

• Many recommendations cite 2:1 to 1:0.8 (glucose:fructose) as optimal. These serve the purpose of enabling maximum carbohydrate intake (up to 100–120 g/h).

• For some athletes, even moderate exercise can mean 25–30 g of fructose per hour —enough to cause flatulence, abdominal pain, or diarrhea.

• Studies show that with 25 g of fructose, well over a third of test subjects experience incomplete absorption, and around a third of those experience significant discomfort. This usually applies under resting conditions—under stress, the symptoms can be significantly worse.

Conclusion: A fixed mix helps many not — it ignores individual differences and physiological stress.

 

2. Why individual differences are crucial

GLUT5 and SGLT1 – our transporters are highly individual

• Fructose is absorbed into the intestinal epithelium via the GLUT5 transporter, glucose via SGLT1. The number and activity of these transporters varies greatly from person to person. 

• Through targeted "good training, " the intestine can learn to absorb larger amounts—especially glucose/maltodextrin via SGLT1. 

This means that for many people—especially those with fructose sensitivity—glucose (or maltodextrin) + low additives are often more tolerable and efficient than gels with a high fructose content.

 

3. Osmolarity – the often underestimated factor for tolerability

• Highly concentrated gels with lots of sugar and additives create high osmolarity → the stomach empties more slowly, water is drawn into the intestines → risk of cramps, nausea, and diarrhea increases.

• Incidentally, simple and double sugars such as glucose, fructose, and sucrose have a significantly higher osmolarity than maltodextrin.

• Conversely, hypo- or iso-osmolar formulations relieve the stomach and intestines—carbs reach the small intestine faster, absorption is more efficient, and there is less strain on the digestive tract.

Therefore, when formulating a "compatible gel," it is not only the type of sugar that counts, but above all osmolarity and minimalism in terms of ingredients.

 

4. Our 30 years of experience – Why SQUEEZY thinks differently

• At SQUEEZY, we don't start with fixed mixing ratios, but with compatibility and individual adaptation.

• In over three decades of working with amateur and professional athletes, we have empirically determined that > 100 g of carbohydrates per hour are possible even without fructose — with maltodextrin + a clean formulation, without stomach problems. 

• Because every body and every microbiome is different, we recommend testing different carbohydrate mixtures. This is the only way to find your personal "fuel zone."

• That's why we now use up to seven different carbohydrate sources in our recipes—many without fructose, some with low or optimal fructose levels for tolerant athletes.

 

5. What you can do as an athlete if you often suffer from stomach/intestinal problems during exercise – 5 practical recommendations

1. Start with fructose-free or low-fructose gels (e.g., maltodextrin, isomaltulose, cyclic dextrin).

2. Look for low osmolarity: as few additives as possible, no unnecessary frills.

3. Test your stomach during training — never for the first time in competition.

4. Increase carbohydrate intake slowly (e.g., 60 → 90 → 120 g/h) while your digestive system adjusts.

5. Observe your reaction: flatulence, cramps, or nausea are signs of intolerance—then make a change instead of gritting your teeth and carrying on.

 

Conclusion: No "one-size-fits-all" solution—instead, individually controllable gels/drinks

A fixed glucose:fructose ratio is no longer appropriate.

The reality is complex: transporter variability, osmolarity, micro- and macro-conditions in the intestine, and individual tolerance make all the difference.

With the right approach—low fructose or fructose-free, well-balanced mixtures, few additives, gradual training—many athletes can achieve high carbohydrate rates without stomach problems.

SQUEEZY offers you exactly this option — a scientifically proven alternative to traditional energy gels.

Here you can find more information about our Basic Formula product range:https://www.squeezy.de/basic-formula/

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