The Study
Carbohydrate mouth-rinsing does not rescue simulated time trial performance in trained endurance cyclists following a 5-day ketogenic diet
This study is like a fair test where cyclists were randomly given either a sugary or fake mouthwash during a bike ride after eating different diets. It shows that the sugary mouthwash didn’t help them go faster after 5 days of a keto diet, even though it might help in other situations.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Some athletes use a sugar mouthwash to feel more energy while biking. This study tested if it helps when they eat no carbs for 5 days.
Where does this study sit?
Systematic Reviews & Meta-analyses
Max 100Randomized Trials
Max 90Cohort Studies
Max 72Case-Control
Max 58Cross-Sectional
Max 44Case Reports & Series
Max 30Expert Opinion
Max 560 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. Considered the gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The slower time is meaningful—almost 3 minutes over 33.6 km—and could affect race outcomes.
- 2No help from mouthwash means brain signals alone can't fix low fuel.
- 3Biking time got 188 seconds slower on no-carb diet.
- 4Sugar mouthwash did not help go faster.
- 5Blood sugar after biking was lower on no-carb diet.
- 6Ketone levels didn't predict how fast they biked.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of the International Society of Sports Nutrition
Year
2025
Authors
Guy Guppy, James Brouner, O. Spendiff
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.