A sharp pain under the ribs just a few kilometres after a gel, gummies, banana, or sports drink can make long-run fueling feel impossible. If running fuel gels cause a side stitch for you, the gel itself may be only part of the problem. The usual trigger is a mismatch between how much you take, how concentrated it is, how much water is available, and how hard you are running when you swallow it.
You do not need to choose between under-fueling and cramping. A simpler fueling plan, practiced at easy effort, usually reveals whether the issue is portion size, fluid timing, product ingredients, or pacing.
Quick Answer
A side stitch after taking running fuel is often exercise-related transient abdominal pain (ETAP), not proof that your body “cannot handle” gels. A full or irritated stomach, concentrated carbohydrate sitting in the gut, gulped fluid, and a sudden increase in running intensity can all make it more likely.
Start by reducing the dose and simplifying the conditions. Take a small amount of fuel every 15 to 20 minutes rather than a full gel at once, use water with gels that require it, and test the plan during easy long runs before race day.
If a particular product repeatedly causes nausea, bloating, diarrhoea, or cramps even at an easy pace with sufficient water, change the product or carbohydrate type. Persistent or severe abdominal pain deserves medical advice rather than more fueling experiments.
Why This Happens
During a run, blood flow is directed toward working muscles and skin for cooling. Digestion still happens, but it is less comfortable and less efficient than it is while resting. Large servings, very sweet drinks, or unfamiliar ingredients can remain in the stomach longer and create a heavy, sloshing sensation.
Many gels are concentrated carbohydrate. That concentration is useful because it packs energy into a small packet, but it can pull water into the intestine if you take it without enough fluid. This may contribute to cramping, urgency, or stomach discomfort. It does not mean every gel must be chased with a huge bottle; it means the product’s instructions and your overall fluid plan matter.
A classic side stitch is commonly felt along the right or left lower rib area. Researchers do not have one complete explanation for every case, but likely contributors include irritation around the abdominal lining, a distended stomach, shallow breathing, posture, and abrupt effort changes. Fuel can be the timing trigger because it adds volume to the stomach just before a hill, surge, or faster kilometre.
Bananas, gummies, and sports drinks can create the same issue for different reasons. A banana adds bulk and fibre. Gummies are easy to overeat because each piece seems small. Sports drink can become overly concentrated if mixed too strongly or used alongside gels without adjusting the plan. The useful question is not “Which fuel is bad?” It is “What total carbohydrate, fluid, and intensity did my gut receive at that moment?”
Step-by-Step Method
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Rule out the obvious timing problem. Avoid taking a full gel immediately before a hill, speed segment, or hard climb. Take fuel on a flatter, easier section, then keep your pace steady for several minutes.
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Start with a conservative carbohydrate target. For runs lasting more than about 75 to 90 minutes, many runners begin around 30 to 45 grams of carbohydrate per hour. That can be enough for a long easy run while you train your gut. Higher targets can work, especially in marathon racing, but should be built gradually.
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Split each serving. Instead of swallowing one 20- to 30-gram gel in seconds, take half over a minute or two and the remainder a few minutes later. Alternatively, choose smaller chews and eat one or two at a time. Smaller doses reduce sudden stomach volume and make it easier to identify your tolerance.
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Match gels to water. Check the packet. Standard gels are generally intended to be taken with water, while isotonic gels contain more fluid but still count toward your carbohydrate intake. Do not wash a gel down with a large volume all at once unless you are also genuinely thirsty. Take normal sips across the next few minutes.
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Use one main carbohydrate source for the test. On a troubleshooting run, do not combine a gel, concentrated sports drink, gummies, and a banana. Pick one product, keep the rest of your intake simple, and record the amount, time, water, weather, and symptoms.
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Practice at easy effort first. Your gut needs training just as your legs do. Test a planned intake on several easy long runs. Once it is comfortable, repeat it during a controlled marathon-pace segment. Race effort, heat, and nerves can lower tolerance, so an easy-run success is the first step, not the final test.
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Change one variable at a time. If symptoms continue, first adjust serving size and water. Next test another flavour or product. Then consider a formula with a different carbohydrate blend, fewer sweeteners, or no caffeine. Changing everything at once leaves you without a useful answer.
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Respond calmly if a stitch starts. Slow slightly, lengthen your exhale, and press gently into the painful area while bending forward a little if that feels relieving. Do not force another gel while your stomach feels tight. Resume small sips and small fuel portions once the pain settles.
Common Mistakes
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Saving all fuel until you feel empty. Hunger or a late-run energy crash often leads to taking a large amount quickly. Instead, begin a steady schedule before you are depleted, usually early in a long run.
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Treating every product as interchangeable. A 25-gram gel, a handful of chews, a banana, and several mouthfuls of sports drink can add up fast. Instead, count approximate carbohydrate per hour from every source.
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Taking fuel just before intensity rises. A gel may seem responsible when the actual trigger is a hill or pace increase moments later. Instead, fuel on easier terrain and delay hard effort briefly.
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Using race-day products for the first time. Different flavours, caffeine levels, and sweeteners can affect tolerance. Instead, use the exact product, flavour, and mixing strength in training.
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Overdrinking to “dilute” a gel. Excess fluid can also create stomach sloshing and discomfort. Instead, drink according to thirst, weather, sweat loss, and the product directions, using regular small sips.
Checklist or Decision Table
| What you notice | Likely issue to test | Practical adjustment |
|---|---|---|
| Stitch appears within minutes of a full gel | Large, fast stomach load | Split the gel into two smaller portions |
| Cramping after gel plus sports drink | Total carbohydrate concentration is too high | Use water with the gel or reduce drink strength |
| Pain starts on hills after fueling | Effort and breathing change | Fuel before the hill on flat terrain |
| Bloating or sloshing | Too much fluid or food volume at once | Take smaller sips and avoid solid fuel close to hard running |
| Symptoms only occur with one brand or flavour | Ingredient or formula intolerance | Test a different formula, lower sweetness, or caffeine-free option |
| Problems only happen in heat | Heat stress and dehydration are reducing gut tolerance | Slow effort, cool down, and use a heat-practiced fluid plan |
When This Advice Does Not Apply
This approach is for common fueling-related discomfort and occasional side stitches during otherwise normal training. It is not a way to push through severe symptoms.
Stop running and seek urgent assessment for chest pain, fainting, severe or worsening abdominal pain, vomiting that will not stop, blood in stool, or pain that does not behave like your usual stitch. Speak with a clinician or sports dietitian if cramps, diarrhoea, reflux, or abdominal pain happen repeatedly even on easy runs with modest fueling. Conditions such as reflux, food intolerances, medication effects, and gastrointestinal disorders need individual guidance.
Also avoid copying high carbohydrate targets from elite marathon plans before your training volume and gut tolerance support them. More fuel is not automatically better; the effective dose is the one you can absorb comfortably while meeting the demands of your run.
Realistic Example
A marathon trainee takes a 25-gram gel at the 30-minute mark of a 16-kilometre long run, washes it down with several large gulps of sports drink, then climbs a bridge at planned marathon pace. At about 3 kilometres after the gel, a sharp right-sided stitch appears. The runner concludes that gels are the problem.
On the next easy long run, the trainee uses the same gel but takes half at 25 minutes and half at 30 minutes, with small sips of water instead of sports drink. The route stays flat for ten minutes after fueling. No stitch occurs. A later test confirms that the previous combination of a full gel, concentrated drink, and uphill effort was the likely trigger. The runner can now build toward a repeatable schedule rather than abandoning fuel entirely.
Final Takeaway
If fuel gels give you a side stitch, first reduce the size and speed of each dose, take the product with an appropriate amount of water, and avoid swallowing it immediately before hard running. Keep total carbohydrate from gels, drinks, and snacks realistic for your current gut tolerance.
Train your fueling plan on ordinary long runs, changing one variable at a time. The best marathon fuel is not the most popular product; it is the one that provides enough carbohydrate without making your stomach a problem.
FAQs
Why do I get a side stitch after taking a running gel?
A side stitch after a running gel is usually linked to stomach distension, concentrated carbohydrate, fluid timing, or a pace increase rather than the gel alone. Taking a full packet quickly can leave a dense bolus in the stomach, particularly if you immediately climb a hill or accelerate. Try taking smaller portions over several minutes and use water if the product directions recommend it. Track whether the stitch occurs with the same dose, route, and effort level before deciding that all gels are unsuitable.
Should I take running gels with water to prevent cramps?
Yes, standard running gels are generally best taken with water, because they are concentrated sources of carbohydrate. Water helps avoid making the contents of your stomach and intestine excessively concentrated, which may reduce the risk of cramps or urgency. You do not need to chug a whole bottle at once; a few normal sips around the gel, followed by regular drinking, is often more comfortable. Check the label, because isotonic gels are formulated differently, although they still need to fit your overall hydration plan.
Can sports drink and gels together cause stomach cramps while running?
Yes, sports drink and gels together can cause cramps when their combined carbohydrate load is higher than your gut can absorb. This is especially common when a runner uses a strong drink mix, takes a full gel, and drinks quickly during warm conditions or hard effort. Count carbohydrates from both products rather than treating the drink as hydration only. For a test run, use water with your gel or lower the drink concentration, then assess comfort before increasing carbohydrate intake again.
How many grams of carbohydrate per hour should a beginner marathon runner use?
A beginner marathon runner can often start with 30 to 45 grams of carbohydrate per hour on long runs lasting more than 75 to 90 minutes. That target is a starting point, not a requirement to force. It may look like one 20- to 25-gram gel every 30 to 40 minutes, adjusted for any carbohydrate in sports drink. Practice the schedule at easy effort for several runs. If it feels comfortable and your training demands more, increase gradually rather than doubling your intake overnight.
Are bananas better than gels for avoiding side stitches on long runs?
No, bananas are not automatically better than gels for avoiding side stitches. They are less concentrated and may feel gentler for some runners, but they also add bulk and fibre, which can be uncomfortable at faster paces. Gels are easier to carry and dose precisely, especially during a marathon, but usually require thoughtful water timing. Test whichever option you prefer under realistic conditions. If bananas work for easy runs but not marathon pace, try smaller gel portions instead of assuming solid food is safer.
What should I do if I get a sharp stitch during a marathon race?
If you get a sharp stitch during a marathon, ease your pace briefly and focus on slow, deep breathing with a long exhale. Gentle pressure on the painful area and a slight forward bend can help some runners. Do not take another large fuel dose while the pain is acute; let your breathing and stomach settle, then resume with small sips and smaller carbohydrate portions. If the pain is severe, unusual, persistent, or accompanied by dizziness, chest pain, or vomiting, stop and seek medical help.