Caffeine Strategies and Fat Oxidation
Effects of Different Caffeine Ingestion Forms on Fat Oxidation During Cycle Ergometer Exercise
1 other identifier
interventional
10
1 country
1
Brief Summary
The goal of this clinical trial is to learn if different forms of caffeine ingestion can influence fat oxidation during submaximal cycling exercise. The study will recruit healthy adults, both men and women, aged 18 to 50, who regularly perform aerobic exercise. The main questions it aims to answer are:
- Does caffeine increase fat oxidation during one hour of cycling at the Fatmax intensity?
- Do different forms of caffeine ingestion (capsule, coffee, chewing gum, or mouth rinse) differ in their effect on fat oxidation?
- Do these caffeine forms alter total energy expenditure, cardiorespiratory response, or perceived exertion during exercise?
- Are there differences in the occurrence or severity of side effects between caffeine administration methods? Researchers will compare each caffeine form to its corresponding placebo to determine their effects on fat oxidation and other physiological outcomes. Participants will:
- Attend a pre-experimental session to determine their Fatmax intensity and VO₂max using an incremental cycling test
- Perform eight experimental sessions, each consisting of one hour of cycling at Fatmax intensity
- Receive caffeine or placebo via capsules, coffee, chewing gum, or mouth rinse according to a randomized, double-blind, crossover design
- Be monitored for fat and carbohydrate oxidation, total energy expenditure, heart rate, and perceived exertion during exercise
- Report any side effects immediately after the session and 24 hours later using a structured questionnaire All sessions will be conducted under controlled laboratory conditions with standardized protocols to ensure safety and reliable measurements.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at below P25 for not_applicable
Started Mar 2026
Shorter than P25 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
January 13, 2026
CompletedFirst Posted
Study publicly available on registry
February 11, 2026
CompletedStudy Start
First participant enrolled
March 15, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
July 31, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
September 30, 2026
April 29, 2026
February 1, 2026
5 months
January 13, 2026
April 28, 2026
Conditions
Outcome Measures
Primary Outcomes (1)
Rate of fat oxidation during submaximal cycling exercise at Fatmax intensity
Continuous measurement of fat oxidation using indirect calorimetry during 1-hour cycling at Fatmax intensity. Calculated from respiratory gas exchange (VO₂ and VCO₂) using Frayn's equations. Unit of Measure: grams per minute (g/min).
1 hour per experimental session
Secondary Outcomes (8)
Rate of carbohydrate oxidation during submaximal cycling exercise at Fatmax intensity
1 hour per experimental session
Total energy expenditure during exercise
1 hour per experimental session
Mean Exercise Heart Rate
1 hour per experimental session
Oxygen consumption
1 hour per experimental session
Carbon Dioxide Production
1 hour per experimental session
- +3 more secondary outcomes
Study Arms (8)
Caffeine capsule
EXPERIMENTALParticipants will ingest 3 mg/kg of anhydrous caffeine powder in an opaque capsule 60 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Placebo capsule
PLACEBO COMPARATORParticipants will ingest an opaque capsule filled with cellulose (placebo) 60 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Caffeine coffee
EXPERIMENTALParticipants will consume 3 mg/kg of caffeine via soluble coffee (Nescafé Classic) in 250 mL of hot water 60 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Placebo coffee
PLACEBO COMPARATORParticipants will consume decaffeinated soluble coffee (Nescafé Descafeinado) in 250 mL of hot water 60 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Caffeine chewing gum
EXPERIMENTALParticipants will chew caffeinated gum (Kafewake) containing 3 mg/kg of caffeine for 10 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Placebo chewing gum
PLACEBO COMPARATORParticipants will chew non-caffeinated gum (Kafewake) with identical flavor and texture for 10 minutes before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Caffeine mouth rinse
EXPERIMENTALParticipants will perform a 20-second mouth rinse with 25 mL of water containing 3 mg/kg of caffeine from soluble coffee (Nescafé Classic) before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Placebo mouth rinse
PLACEBO COMPARATORParticipants will perform a 20-second mouth rinse with 25 mL of water containing decaffeinated soluble coffee (Nescafé descafeinado) before performing 60 minutes of cycling on a cycle ergometer at Fatmax intensity.
Interventions
3 mg/kg of anhydrous caffeine powder (Guinama, Spain) administered in an opaque capsule 60 min before exercise.
3 mg/kg of caffeine via Nescafé Classic (Nestlé, Switzerland) dissolved in 250 mL of water 60 min before exercise.
3 mg/kg of caffeine via Kafewake gum (Arafarma group, Spain), chewed for 10 min before exercise.
3 mg/kg of caffeine (Nescafé Classic) dissolved in 25 mL of water for a 20-second rinse before exercise.
Opaque capsule containing cellulose powder, matching caffeine capsules, taken 60 min before exercise.
Decaffeinated Nescafé (Nestlé, Switzerland) in 250 mL of water, matching caffeinated coffee, taken 60 min before.
Kafewake Non-caffeinated gum (Arafarma group, Spain) with identical taste and texture, chewed for 10 min before.
Decaffeinated Nescafé in 25 mL of water for a 20-second rinse immediately before exercise.
Eligibility Criteria
You may qualify if:
- Healthy men and women aged 18-50 years
- Regular aerobic exercise at least 1 hour per day, 2 days per week
- Provide written informed consent
You may not qualify if:
- Smoking
- Use of medication or ergogenic supplements during the study period
- Caffeine intolerance or allergy
- Cardiopulmonary or musculoskeletal disorders
- Use of oral contraceptives in female participants
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Estadio Raúl González Blanco, Camino del Molino 5
Fuenlabrada, Madrid, 28942, Spain
Related Publications (2)
Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021 Jan 2;18(1):1. doi: 10.1186/s12970-020-00383-4.
PMID: 33388079RESULTRuiz-Moreno C, Gutierrez-Hellin J, Amaro-Gahete FJ, Gonzalez-Garcia J, Giraldez-Costas V, Perez-Garcia V, Del Coso J. Caffeine increases whole-body fat oxidation during 1 h of cycling at Fatmax. Eur J Nutr. 2021 Jun;60(4):2077-2085. doi: 10.1007/s00394-020-02393-z. Epub 2020 Oct 6.
PMID: 33025051RESULT
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Juan Del Coso, PhD
Universidad Rey Juan Carlos
- PRINCIPAL INVESTIGATOR
Arturo Casado, PhD
Universidad Rey Juan Carlos
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- DOUBLE
- Who Masked
- PARTICIPANT, INVESTIGATOR
- Purpose
- BASIC SCIENCE
- Intervention Model
- CROSSOVER
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Principal Investigator
Study Record Dates
First Submitted
January 13, 2026
First Posted
February 11, 2026
Study Start
March 15, 2026
Primary Completion (Estimated)
July 31, 2026
Study Completion (Estimated)
September 30, 2026
Last Updated
April 29, 2026
Record last verified: 2026-02
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL, SAP, ICF
- Time Frame
- De-identified individual participant data may be shared after the publication of the main study findings and will remain available for up to three years following publication.
- Access Criteria
- Access to any de-identified individual participant data will be considered on a case-by-case basis. Requests will require a scientifically sound proposal and may be subject to additional ethical review and data use agreements, in accordance with institutional and legal requirements. The study investigators reserve the right to decline requests.
De-identified individual participant data underlying the results reported in publications may be made available upon reasonable request. These data may include anonymized metabolic, ventilatory, cardiovascular and perceptual variables collected during the study (e.g., fat oxidation rate, energy expenditure, VO₂, VCO₂, heart rate, capillary blood lactate concentration, and ratings of perceived exertion). Any data sharing will be subject to ethical approval, compliance with applicable data protection regulations, and approval by the study investigators.