Scientists reviewed 35 studies about a simple trick athletes use: swishing a sugary drink in their mouth for a few seconds without swallowing it. They found that when athletes do this after eating a meal, it actually helps them exercise better and think more clearly. The sugar doesn’t need to be digested—just touching the taste buds in your mouth sends signals to your brain that improve focus and physical performance. This discovery could help athletes perform better without needing to eat more food right before competition.

The Quick Take

  • What they studied: Does swishing a sugary drink in your mouth for a few seconds help athletes perform better when they’ve already eaten a meal?
  • Who participated: Researchers combined results from 35 different studies involving healthy adults who did exercise or thinking tasks after eating food. Most studies focused on athletes and active people.
  • Key finding: Swishing sugar water in your mouth improved exercise performance by a small but real amount (about 18% improvement). The effect was stronger when athletes had recently eaten a high-carbohydrate meal and used specific types of sugar solutions.
  • What it means for you: If you’re an athlete, swishing a sugary drink for 10 seconds or less after eating might give you a small performance boost during aerobic exercise like running or cycling. However, the improvement is modest, and more research is needed to confirm these findings work for everyone.

The Research Details

Scientists searched six major research databases for studies comparing sugar mouth rinsing to fake treatments (placebos) in people who had already eaten. They found 35 studies that met their strict requirements—all had to be well-designed experiments with healthy adults doing either exercise or mental tasks. Two studies looked at thinking and memory, while 33 focused on physical exercise performance.

The researchers used advanced statistical methods to combine results from all these studies together. This approach, called a three-level meta-analysis, is like combining puzzle pieces from many different experiments to see the bigger picture. They also looked at what factors made the sugar rinsing work better or worse, such as the type of sugar used, how long people rinsed, and what they had eaten beforehand.

This type of study is considered very strong evidence because it combines many individual experiments rather than relying on just one study.

Previous research on sugar mouth rinsing mostly studied people who hadn’t eaten anything (fasting). This new review specifically looks at what happens when athletes have already eaten a meal, which is more realistic for real-world sports. Understanding how this trick works in fed conditions helps coaches and athletes know when and how to use it effectively.

The overall certainty of evidence is low to moderate. While 35 studies is a good number, many individual studies had small numbers of participants. The researchers were careful to only include high-quality, controlled experiments, which strengthens their conclusions. However, more large-scale studies are needed to be completely confident in these findings.

What the Results Show

When athletes swished sugar water in their mouth after eating a meal, their exercise performance improved by a small but measurable amount. The improvement was about 18% better than when they used a fake sugar solution (placebo). This effect was consistent across the studies reviewed.

The sugar rinsing worked best during aerobic exercise—activities like running, cycling, or swimming where your heart rate goes up. It was less effective for strength training or short, intense bursts of activity. The type of sugar mattered too: maltodextrin (a specific type of processed sugar) worked better than other sugar types.

Timing and technique were important. Rinsing for 10 seconds or less was more effective than longer rinses. Also, the sugar rinsing worked better when athletes had eaten a meal high in carbohydrates (like pasta, bread, or rice) before exercising, rather than a low-carb meal.

For thinking and memory tasks, the sugar rinsing also appeared to help, but the evidence was much weaker because only two studies looked at this. Scientists need more research to be confident about mental performance benefits.

The research showed that the benefits of sugar mouth rinsing don’t depend on the sugar actually being digested or absorbed into the bloodstream. Instead, taste receptors in your mouth send signals directly to your brain that improve motivation and focus. This is important because it means the effect happens immediately, without waiting for digestion. The studies also found that the effect was similar for both men and women, and for both trained athletes and less experienced exercisers, though more research is needed to confirm this.

Earlier studies mostly tested sugar mouth rinsing in people who hadn’t eaten anything (fasting state), and found it helped performance. This new review shows that the trick still works even after eating—and might actually work better. This is important because athletes often eat before competing, so knowing it works in fed conditions makes it more practical for real sports situations.

The studies reviewed had relatively small numbers of participants, which means the results might not apply perfectly to everyone. The certainty of evidence for cognitive (thinking) benefits is very low because only two studies examined this. Different studies used slightly different methods and measured performance in different ways, which can make combining results tricky. More research with larger groups of people is needed to confirm these findings and understand exactly how the effect works in the brain.

The Bottom Line

For aerobic athletes (runners, cyclists, swimmers): Swishing a maltodextrin-based sugar solution for 10 seconds or less after eating a high-carbohydrate meal may provide a small performance boost. Confidence level: Low to Moderate. For strength athletes or those doing short, intense activities: The evidence is weaker, so this trick may not help as much. Confidence level: Low. For cognitive performance: The evidence is too limited to recommend this practice. Confidence level: Very Low.

Competitive aerobic athletes might benefit most from trying this technique. Recreational exercisers probably won’t notice much difference. People with diabetes or blood sugar concerns should talk to their doctor before trying this. This is not a replacement for proper nutrition and training—it’s just a small potential boost.

The performance improvement happens immediately—within minutes of rinsing. You won’t see long-term fitness improvements from this trick alone. It’s meant as a quick performance boost for specific workouts or competitions, not as a daily practice.

Want to Apply This Research?

  • Log pre-exercise meals (especially carbohydrate content), sugar rinse timing and type, and exercise performance metrics (distance, time, or perceived effort) to track whether this technique works for your individual performance.
  • Before your next aerobic workout, try swishing a maltodextrin solution (sports drink or specialized product) for 10 seconds after eating a carb-rich meal. Note your performance and how you felt compared to normal workouts.
  • Track performance over 4-6 weeks of using this technique during similar workouts. Compare your times, distances, or effort levels on days you use the sugar rinse versus days you don’t. Keep notes on what you ate beforehand and the type of sugar solution used.

This research summary is for educational purposes only and should not replace professional medical or sports nutrition advice. The findings represent current scientific evidence but have low to moderate certainty. Athletes with diabetes, blood sugar disorders, or other health conditions should consult their healthcare provider or sports dietitian before using carbohydrate mouth rinsing. Individual results may vary, and this technique is not a substitute for proper training, nutrition, and recovery. Always follow your sport’s rules regarding allowed performance aids.