Ethan BrooksBy Ethan Brooks

Updated November 2026

Energy gels cause stomach cramps mainly because they deliver a concentrated dose of carbohydrate into the gut faster than your body can absorb it, especially when they are taken without enough water or during hard effort. The fix is usually simple: change the timing, dilute the dose with fluid, and test your plan before race day.

Why Energy Gels Trigger Cramping

A typical gel packs a large amount of carbohydrate into a small, thick volume. Your small intestine absorbs glucose and fructose through specific transporters, and those transporters have a limited capacity per hour. When the load arrives faster than it can be absorbed, sugar stays in the gut, draws water into it, and ferments. The result is bloating, cramping, and sometimes urgency.

Blood flow matters too. During hard running, your body diverts blood toward working muscles and away from the digestive tract. A gel that would sit fine during an easy jog can feel heavy and crampy at tempo pace or on a steep climb.

Factors That Make Cramps Worse

  • Taking gels without fluid. Concentrated sugar needs water to move through the gut. Dry gel intake is a common cramp trigger.
  • Stacking gels too closely. Two gels back to back can overwhelm absorption even if each one is tolerable alone.
  • Unfamiliar brands or flavors. Some gels use higher fructose ratios or added fiber or caffeine, which can change how your stomach responds.
  • Going out too fast. Early race effort often pushes gut blood flow down just when you start fueling.
  • Low training exposure. Guts adapt. Runners who never practice fueling on long runs tend to have more problems on race day.

Most runners can cut cramping significantly by adjusting a few variables and rehearsing them in training. Manufacturers typically recommend taking gels with water, and many coaches suggest starting around 30 to 45 minutes into a long effort and repeating at intervals that fit the product’s carbohydrate content. Check the label for the intended dose, and do not exceed it.

  1. Take each gel with 4 to 6 ounces of water, not with a sports drink that adds more sugar to the same load.
  2. Space gels about 30 to 45 minutes apart rather than clustering them.
  3. Drop your effort slightly for 60 to 90 seconds while you take the gel, and walk through aid stations if needed.
  4. Test your plan on at least two long runs, including one at race pace, before committing to it.
  5. If cramps persist with a specific gel, switch to a lower-concentration option or a different carbohydrate blend.

For timing details, see When to Take Energy Gels: A Marathoner's Timing Guide. If you are weighing ingredient differences, Why Is There Maltodextrin in Energy Gels? Purpose and Trade-Offs explains how carbohydrate type affects absorption.

What We’d Use

If you are looking for a gel with a reputation for being easier on the stomach, a gentler formulation with a balanced carbohydrate blend is a reasonable place to start. Look for options marketed as low-fiber or single-serve, and compare them using the picks in Energy Gels Gentle on Stomach: 5 Best Picks Compared (2026).

  • Maurten Gel 100 – a carbohydrate gel many runners try when standard gels cause problems. View on Amazon
  • GU Energy Gel – a widely available option that is easy to test in training. View on Amazon

FAQ

Can I take energy gels on an empty stomach?

Most runners do better starting gels after the first 30 to 45 minutes of a long effort, once a light breakfast has settled. Taking one fasted right before the start often increases cramping risk.

Does drinking more water stop gel cramps?

Water helps the gut process concentrated sugar, but it will not fix a dose that is too large or too frequent. Pair water with appropriate spacing for the best results.

When should I see a doctor about stomach pain while running?

Severe or persistent pain, blood in stool, vomiting, or dizziness are reasons to stop and seek medical care. Consult a physician or sports medicine professional if symptoms keep recurring despite changes to your fueling.

Ready to choose one?

Ethan Brooks

About Ethan Brooks

Ethan Brooks is part of our editorial team and reviews and edits our marathon & half-marathon guides, checking product details against manufacturer specifications and owner feedback.