A Study to See if an Energy Drink With Caffeine and Green Tea Increases Fat Burning When Exercising

Influence of Caffeine and Green Tea Extracts Consumption on Basal, Peri- and Post-exercise Fat Oxidation

The goal of this study is to evaluate the influence of consuming a drink containing a combination of caffeine and green tea extracts on fat oxidation responses at rest, during and after a period of endurance type exercise.

Study Overview

• Status: Recruiting
• Conditions: Exercise
• Intervention / Treatment: Dietary supplement: Active (Green tea and caffeine); Other: Placebo

Detailed Description

This study investigates whether consuming an energy drink containing caffeine and green tea extract before exercise increases fat burning (oxidation) compared with a placebo drink. Healthy, moderately active adults will attend three visits at clinic over 3-5 weeks. The first visit determines each participant's individual exercise intensity that maximises fat use during cycling. At two subsequent visits, participants will consume either the active drink or a placebo before completing a 30-minute cycling session at their personalised intensity. Fat and carbohydrate use, heart rate, blood pressure, and subjective responses will be measured at rest, during exercise, and after exercise using a double-blind, crossover design.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Llion Roberts, PhD; Phone Number: +61755528451; Email: Llion.Roberts@Griffith.edu.au

Study Locations

• Australia
  • Queensland
    • Southport, Queensland, Australia, 4222
      • Recruiting
      • Griffith University, Gold Coast Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Passing the Exercise and Sport Science Australia adult pre-exercise screening system (APSS) stage 1 & 2 (see appendix 4).
• Between the ages of 18 and 45,
• Not sedentary, and not completing more than 150 minutes of low and/or moderate and/or or vigorous intensity endurance exercise a week,
• Ability to commit to in principle fulfilment of all 3 trial visits,
• No history of coagulopathy e.g., DVT, stroke,
• No known heart disease,
• No known pancreatic insufficiency,
• No known inflammatory bowel disease, or prior bowel resection or bypass surgery (excluding gastric banding and sleeve),
• BMI of 22.0 to 34.9 kg/m2,
• No known allergies to caffeine or green tea extract,
• No known type I or II diabetes,
• No uncontrolled concurrent illness,
• No known current pregnancy or breastfeeding women
• No current regular consumption of supplements (>2 times a week) or foods and drinks containing caffeine and/or green tea extracts (>2 times per day, weekly).
• Agree not to consume caffeine for 12-hours prior to the clinic visit.

Exclusion Criteria:

• Triggering any of the exclusion screening criteria as outlined below, and in compliment with the Exercise and Sport Science Australia adult pre-exercise screening system (APSS).
• Under the age of 18 or over the age of 45,
• Sedentary, or completing over 150 minutes of low and/or moderate and/or or vigorous intensity endurance exercise a week,
• Inability to commit to in principle fulfilment of all 3 trial visits,
• History of coagulopathy e.g., DVT, stroke,
• Known heart disease,
• Known pancreatic insufficiency,
• Known inflammatory bowel disease, or prior bowel resection or bypass surgery (excluding gastric banding and sleeve),
• BMI < 22.0 or > 34.9 kg/m2,
• Known allergies to caffeine or green tea extract,
• Known type I or II diabetes,
• Uncontrolled concurrent illness,
• Taking GLP-1 agonists, caffeine, or any other medication known to affect metabolism.
• Known current pregnancy or breastfeeding women.
• Currently regularly consuming supplements, foods or drinks containing a caffeine and green tea extract blend, or not willing to abstain for the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active; Two 355 mL cans of "XS Energy + BURN" drink containing caffeine and green tea extract.	Dietary supplement: Active (Green tea and caffeine); Two 355 mL cans of "XS Energy + BURN" drink containing caffeine and green tea extract.; Other Names: XS Energy + BURN
Other: Placebo; Two 355 mL cans of placebo drink but without the active ingredients (caffeine and green tea extract).	Other: Placebo; Two 355 mL cans of placebo drink but without the active ingredients (caffeine and green tea extract).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fat oxidation as measured by indirect calorimetry	Change from baseline to the end of the study period in Fat oxidation as measured by indirect calorimetry (metabolic cart); baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise. Change from baseline & total. Fat oxidation will be measured continuously throughout the exercise and the 30-min post-exercise window, to facilitate total, and any other temporal fat oxidation timepoints.	Baseline to 30 mins post exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carbohydrate oxidation; indirect calorimetry	Change from baseline to the end of the study period in Carbohydrate oxidation; indirect calorimetry; same timing as fat oxidation (baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise.). Change from baseline & total.	Baseline to 30 mins post exercise
Respiratory exchange ratio; indirect calorimetry	Change from baseline to the end of the study period in Respiratory exchange ratio; indirect calorimetry; same timing as fat oxidation (baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise). Change from baseline & total	Baseline to 30 mins post exercise
Exercise efficiency; indirect calorimetry	Change from baseline to the end of the study period in Exercise efficiency; indirect calorimetry; time sequence during exercise e.g., every 5-min. Change from the beginning of exercise & average	Baseline to 30 mins post exercise

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tertiary: Compliance monitoring	Compliance monitoring for adherence to clinical trial components e.g. consumed volume of investigational product; ability to complete the necessary duration (30 mins) and intensity (at fat max) of exercise; adherence to immediate pre-trial control procedures of no caffeine or green tea extract in the 12 hours leading up to the experimental, arrival at the laboratory after an overnight fast	Baseline to end of study period (week 5)
Tertiary: Adverse Event monitoring	Adverse events will be monitored throughout the study across the study periods.	Baseline to end of study period (week 5)
Tertiary: Perceived gastrointestinal (dis)comfort questionnaire	Change from baseline to the end of the study period in Perceived gastrointestinal (dis)comfort; measured via a questionnaire.	Baseline to end of study (week 5)
Tertiary: Perceived satiety / hunger	Change from baseline to the end of the study period in Perceived satiety / hunger; measured via questionnaire.	Baseline to end of study period (week 5)
Tertiary: Perceived exercising exertion	Change from baseline to the end of the study period in Perceived exercising exertion; measured via questionnaire.	Baseline to end of study period (week 5)
Tertiary: heart rate	Change from baseline to the end of the study period in heart rate. Pre, during and post exercise heart rate.	Baseline to end of study period (week 5)
Tertiary: blood pressure	Change from baseline to the end of the study period in blood pressure. Pre, during and post exercise blood pressure.	Baseline to end of study period (week 5)
Tertiary: Safety via AE monitoring	Change from baseline to the end of the study period in safety via AE monitoring.	Baseline to end of study period (week 5)
Tertiary: Anthropometry - BMI	Change from baseline to the end of the study period in BMI.	Baseline to end of study period (week 5)
Tertiary: Anthropometry - weight	Change from baseline to the end of the study period in weight.	Baseline to end of study period (week 5)
Tertiary: Anthropometry - waist circumference	Change from baseline to the end of the study period in waist circumference.	Baseline to end of study period (week 5)

Collaborators and Investigators

• Sponsor: RDC Clinical Pty Ltd
• Collaborators: Amway Corp

Study record dates

Study Major Dates

• Study Start (Actual): March 26, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: January 5, 2026
• First Submitted That Met QC Criteria: February 19, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): April 16, 2026
• Last Update Submitted That Met QC Criteria: April 13, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: metabolism
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Alkaloids; Purinones; Purines; Beverages; Plant Preparations; Biological Products; Complex Mixtures; Xanthines; Caffeine; Exercise; Tea
• Other Study ID Numbers: GRIFEX

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No