How to Avoid Stomach Issues When Consuming Energy Gels?
Reading time: 8 min

How to Avoid Stomach Issues When Consuming Energy Gels?

Reading time: 8 min
Learn all you need to know to avoid stomach issues during exercise!
How to Avoid Stomach Issues When Consuming Energy Gels?

Energy gels are an essential fueling supplement for endurance athletes that provide carbohydrates and electrolytes during intense exercise, but they often have an unwanted side effect – stomach issues.

The best way to avoid stomach issues when consuming energy gels is to choose an energy gel that contains both fructose and glucose. Additionally, it is important to train your gut and follow a sensible fueling strategy. Finally, be sure to consume the appropriate foods before exercising. 

In this blog, we'll discuss stomach issues caused by energy gel consumption and how to avoid them.

Why energy gels cause stomach issues?

You have sufficiently trained your gut and consume the prescribed amount of energy gels per hour, but you still experience stomach issues during intense exercise.

Why is that?

It comes down to ingredients.

The two main ingredients of any energy gel are carbohydrates and minerals, and both may cause digestive issues.

Why do carbohydrates cause digestive issues?

It is well established that during intense exercise your body needs a fast-acting sugar as its preferred source of energy due to the fact that at high intensity, your digestion is impaired and your body tends to consume its glycogen stores instead of food in the stomach.

A fast-acting sugar, such as glucose, has a very high absorption rate and will, at least in part, replace glycogen as the source of energy. But keep in mind that even glucose will only slow down glycogen consumption and not completely prevent it, so no energy gel will keep you going forever.

While most energy gels are well aware of this fact and provide glucose, or its fancy cousin maltodextrin, as the source of energy, most of them neglect the limits of the carbohydrate transporters in your body. 

Carbohydrate transporters?

In simple terms, it's proteins that transport carbohydrates across your body. Basically, if you want your muscles to get the energy from the food you consume, you need to take it there. That's the role of carbohydrate transporters.

There are two carbohydrate transporters involved in the process. SGLT1 and GLUT5. What's the difference between the two? It's simple, one transports glucose and the other transports fructose.

And here lies the answer. Both of these transporters have their limits. SGLT1 can transport up to 60 grams of glucose per hour, and GLUT5 can transport up to 30 grams of fructose per hour. The trick is that while both have their limits, they don't get in each other's way. In other words, when working together, they can transport up to 90 grams of carbohydrates per hour.

Since many fueling guides instruct you to consume up to 90 grams of carbohydrates per hour, you will run into problems, i.e. stomach issues, if the only source of carbs in your energy gel is glucose.

And since most energy gels only contain glucose (or maltodextrin), you can see why stomach issues are so common when using energy gels.

Why do minerals cause digestive issues?

This is a funny one. It all comes down to magnesium, really.

Wait, what?

Yes, you read that correctly. One of the common offenders in terms of stomach issues is this pesky little mineral called magnesium.

I don't get it, isn't magnesium the miracle mineral that prevents muscle cramps and every athlete is happy to load up on?

Well, yes it is. And no, it is not. Magnesium has been marketed for decades as the best way to prevent muscle cramps during intense exercise. The truth is that the occurrence of muscle cramps is far more complex and magnesium alone will hardly accomplish that task, if at all, but that can't change the mind of the athletes, who often worship magnesium as the holy grail of supplements.

Don't get us wrong, magnesium is in fact an extremely important mineral, and it may be one of the factors that prevent muscle cramps, but the reality is that you lose very little magnesium in your sweat, so supplementing it in large quantities provides no benefits.

On the other hand, magnesium is also known for and often used for its laxative effect. And now, if you combine laxative effect with large quantities, you probably get the same result as we did. Yup, stomach issues.

Energy gels may cause stomach issues because they only contain glucose or because they contain too much magnesium.

How to train the gut?

Training your gut means that you gradually train your body to absorb carbohydrates during exercise.

Start training without any carbohydrates or a low quantity of carbohydrates, then gradually increase your intake until you reach the desired amount. Be mindful of how you feel and have patience. As with all things, consistent training will yield the desired results.

While training your gut, it is especially important to eat the right foods before exercise, which fundamentally means avoiding dietary fiber and fat, as the food in your stomach will greatly impact the occurrence of stomach issues during exercise.

It also makes sense to stick to a specific brand of supplements when training your gut, as different supplements might have different concentrations of nutrients, which leads to unexpected results.

And a word of wisdom, never try a new brand of supplements on race day! Always test your supplements during training to make sure your body tolerates them well.

Training your gut means gradually training your body to absorb carbohydrates.

What to eat during exercise?

During exercise you should primarily eat carbohydrates. This is called fueling. While fueling is not essential for exercise that lasts less than 2 hours, it becomes increasingly important as the length of your exercise increases.

While the aim of fueling is to get energy to fuel your performance, avoiding stomach issues is an important part of it. In this regard, fueling can get a little tricky, as failing to provide enough carbohydrates will deplete your energy levels too soon, while exceeding your intake will inevitably lead to stomach issues.

The optimal intake for you depends on many factors, such as exercise length and intensity, how trained you are to absorb carbohydrates, the specific supplements you use, and your diet before exercise.

Top-level athletes consume 90 grams of carbohydrates per hour, and many professional athletes have started to up the intake to even 120 grams per hour. But such an intake is extremely high. For most athletes, consuming 60 grams of carbohydrates per hour may be well enough.

If your goal is to be the best, then you should always aim to increase your carbohydrate intake as much as possible. But if you wish to train or race as a recreational athlete, getting enough energy while avoiding stomach issues is all it takes.

If you want to avoid stomach issues, you must follow an appropriate fueling strategy.

What should I eat before exercise?

As with all things related to nutrition, different athletes respond differently. One athlete may be able to eat an hour before a race and feel great, while another might need several hours to digest the food they eat.

But the rule of thumb is to avoid dietary fiber and fat, as they will both burden your digestive system and provide no benefit to your performance.

On the other hand, loading up on carbs is a nutritional strategy used by athletes of all levels to fill their glycogen stores as much as possible before a training session or race.

There is no need to get too fancy here. Try to eat as many simple carbs as you can tolerate before a race. This process is called carb-loading. While many athletes begin their carb-loading days before the event, you might get by simply with a carbohydrate-rich breakfast hours before the race.

In the end, it all depends on your goals and circumstance. The shorter the exercise, the less important it is what you eat beforehand. But if you are planning to run a marathon, nutrition becomes very important. And if that's your plan, we have the guide for you.

It is advisable to avoid dietary fiber and fat before a hard training session or race.

What energy gel doesn't cause stomach issues?

As said, any energy gel may cause stomach issues if your gut is not sufficiently trained or if you consume excessive amounts of energy gels.

But with that in mind, the energy gel that is likely to not cause stomach issues contains a combination of glucose and fructose and the correct concentration of minerals, especially low quantities of magnesium.

Ok, that's great in theory, but does such an energy gel exist?

Well, of course it does. Actually, we will give you two.

4Energy Gel

The main reason why we praise this energy gel is because we have made it ourselves!

Yes, we are a little biased here.

But we are athletes ourselves and we know what stomach issues during a race feel like. Especially with your mom and girlfriend watching. Not ideal, that's for sure.

So we set out to create an energy gel that will never cause us stomach issues again. The result is 4Energy Gel. And since this is one of the most popular supplements in our store, we believe we've done our job well.

Why do athletes love 4Energy Gel?

Because it doesn't cause stomach issues, duh. It is also sweetened with freshly-squeezed fruit juice, doesn't need any water to be consumed, and has a uniquely refreshing taste.

And in case you wonder, it contains a combination of glucose and fructose and a low quantity of magnesium.

It is also reasonably priced and sports a stylish look. Sure to impress!

Nrgy Unit Gel

Another brand that we like and is dedicated to avoid stomach issues at all cost is Nduranz, which creates supplements for top-level and professional athletes.

One of their flagship products is Nrgy Unit Gel, an energy gel that packs an astounding 45 grams of maltodextrin and fructose per gel. If you want to sustain the extremely high intake of carbs required by intense endurance exercise at the highest level, this bad boy is a great way to do it.

Nrgy Unit Gel also contains Nduranz Electrolyte Mix, which aims to replace exactly the minerals you lose in your sweat during exercise. This way you can sustain optimal hydration throughout your exercise and avoid stomach issues. Great stuff.

This energy gel is not the cheapest gel on the market, but if you're looking for top performance, it's definitely worth the price tag.


Energy gels are a great source of energy during intense endurance exercise, but they often cause stomach issues.

To avoid stomach issues, choose the right energy gel, train your gut, eat the correct foods before the event, and follow an appropriate nutritional strategy.

The correct energy gel contains a combination of glucose (maltodextrin) and fructose and the correct concentration of minerals, namely low quantities of magnesium.

The energy gels we recommend to avoid stomach issues during exercise are 4Energy Gel and Nrgy Unit Gel.

Nrgy Unit Gel BoxNrgy Unit Gel Box

16 x 75 g

45 g CHO per gel with electrolytes

Regular price€39,99 Sale price€16,00
- 60%
4Energy Gel Box4Energy Gel Box

24 x 60 ml

Natural, no water needed

Regular price€48,00 Sale price€24,00
- 50%
GO Isotonic Energy Gel BoxGO Isotonic Energy Gel Box
SIS - Science in Sport

30 x 60 ml

No water needed

Regular price€66,00 Sale priceFrom €29,70
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Energy Gel with L-Carnitine BoxEnergy Gel with L-Carnitine Box
4Endurance Pro

24 x 60 ml

Get energy, boost fat metabolism

Sale price€54,99