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Trial registered on ANZCTR


Registration number
ACTRN12625000323426
Ethics application status
Approved
Date submitted
20/02/2025
Date registered
17/04/2025
Date last updated
17/04/2025
Date data sharing statement initially provided
17/04/2025
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effect of artificial sweeteners on substrate utilisation at rest and during sub-maximal exercise in recreationally active adults (a Pilot Study)
Scientific title
The effect of artificial sweeteners on substrate utilisation at rest and during sub-maximal exercise in recreationally active adults (a Pilot Study)
Secondary ID [1] 314004 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Diabetes 336736 0
Condition category
Condition code
Metabolic and Endocrine 333265 333265 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study investigates the effect of artificial sweeteners (AS) on substrate utilisation at rest and during exercise. In a randomised, counter-balanced crossover design, each participant will complete three experimental trials following a VO2max test. Participants will consume one of three beverages across three sessions:

Artificially sweetened sports drink

Full-sugar sports drink

Water (control condition)

Each beverage will be consumed in a total volume of 1000mL, administered in three doses: 500mL prior to exercise, followed by 250mL at 15 minutes and 250mL at 25 minutes during the exercise protocol.

The artificially sweetened sports drink used is Gatorade Sports Drink Sugar Free Grape Electrolyte Hydration Bottle, containing sucralose (955) and acesulfame potassium (950) as sweeteners, with 0g carbohydrate.

The full-sugar drink is the standard Gatorade Grape Electrolyte Hydration Bottle, containing approximately 60g carbohydrate per 1000mL, derived from sucrose and glucose.

The water condition serves as the control, with no caloric content.

All beverages are administered one-on-one by a researcher (Exercise Physiologist Honours Student) in a laboratory setting. Adherence is monitored through direct observation of beverage intake and collection of empty bottles to ensure full consumption.

Exercise Component

Visit 1 – VO2max Test and Familiarisation
Participants complete an incremental VO2max test using a progressive ramp protocol on a cycle ergometer, with the aim of determining their maximal aerobic capacity and lactate threshold (LT).

Starting at 10% estimated Wmax, load increases by 10% per minute until volitional exhaustion. Continuous gas exchange analysis is performed using a COSMED metabolic cart. Heart rate, blood glucose, blood lactate, and blood pressure are assessed pre- and post-test. A 5-minute active recovery is followed by a 20-minute familiarisation ride at 50% Wmax to practise sampling procedures.

Visits 2–4 – Submaximal Trials (Beverage Conditions)
After the 7-day washout following Visit 1, participants complete three 90-minute experimental trials, each associated with one beverage condition. Exercise is performed on a cycle ergometer, with workload prescribed based on individual LT derived from Visit 1.

Pre-Exercise Phase
Participants consume 500mL of the assigned beverage upon arrival. This is followed by 10 minutes of resting data collection, and 20 minutes of post-beverage metabolic assessment, including gas exchange and finger-prick blood glucose and lactate.

Exercise Protocol

Warm-up: 10 minutes at 25% LT

Main trial: 40 minutes continuous cycling at 90% LT, with two additional beverage doses (250mL at minutes 15 and 25), and monitoring of gas exchange, heart rate, Borg RPE, and blood lactate/glucose every 10 minutes

Cool-down: 10 minutes at 20% LT, followed by final physiological measures

All sessions are supervised by no fewer than two trained researchers to ensure safety, consistency, and protocol fidelity.

A minimum 7-day washout period is observed between each beverage condition.
Intervention code [1] 330613 0
Treatment: Other
Comparator / control treatment
Participants will consume water as the control treatment. The study employs a counterbalanced, cross-over design, where each participant acts as their own control.
Control group
Placebo

Outcomes
Primary outcome [1] 340836 0
Fat oxidation during sub-maximal exercise
Timepoint [1] 340836 0
1. Pre-exercise final baseline (after warm-up, before exercise begins) 2. 10 min into exercise 3. 15 min into exercise (first 250mL beverage dose consumed) 4. 25 min into exercise (second 250mL beverage dose consumed) 5. 30 min into exercise 6. 40 min into exercise (end of exercise session) 7. Immediately post-exercise 8. 10 min into cooldown 9. Final post-exercise measurement (end of cooldown)
Primary outcome [2] 340961 0
Fat oxidation at rest
Timepoint [2] 340961 0
1. Baseline (pre-ingestion) 2. Post-ingestion resting period (20 minutes after consuming 500mL of the assigned beverage)
Secondary outcome [1] 445205 0
Blood glucose at rest
Timepoint [1] 445205 0
1.Baseline (pre-exercise, before beverage consumption) 2. 20 min post-beverage consumption
Secondary outcome [2] 445206 0
Blood glucose during exercise
Timepoint [2] 445206 0
1. Pre-exercise final baseline (after warm-up, before exercise begins) 2. 10 min into exercise 3. 15 min into exercise (first 250mL beverage dose consumed) 4. 25 min into exercise (second 250mL beverage dose consumed) 5. 30 min into exercise 6. 40 min into exercise (end of exercise session) 7. Immediately post-exercise 8. 10 min into cooldown 9. Final post-exercise measurement (end of cooldown)
Secondary outcome [3] 445207 0
Blood lactate at rest
Timepoint [3] 445207 0
1.Baseline (pre-exercise, before beverage consumption) 2. 20 min post-beverage consumption
Secondary outcome [4] 445606 0
Blood lactate during sub-maximal exercise
Timepoint [4] 445606 0
1. Pre-exercise final baseline (after warm-up, before exercise begins) 2. 10 min into exercise 3. 15 min into exercise (first 250mL beverage dose consumed) 4. 25 min into exercise (second 250mL beverage dose consumed) 5. 30 min into exercise 6. 40 min into exercise (end of exercise session) 7. Immediately post-exercise 8. 10 min into cooldown 9. Final post-exercise measurement (end of cooldown)

Eligibility
Key inclusion criteria
Key Inclusion Criteria
Aged 22–35 years
Healthy, recreationally active individuals (exercising at least 3 times per week)
Able to cycle for 40 minutes continuously
Willing to abstain from caffeine, alcohol, and strenuous exercise for 24 hours before testing sessions
Willing to undergo finger-prick blood sampling
Able to attend all four study visits at the University of Sydney
Minimum age
22 Years
Maximum age
35 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Medical conditions including:
Hypertension
Cardiovascular disease
Respiratory disorders (e.g., asthma)
Metabolic disorders (e.g., diabetes)
Clinically diagnosed thyroid conditions
Taking prescribed medications for hypertension, cholesterol, or insulin resistance
Pregnancy
Currently undergoing rehabilitation for a musculoskeletal or joint injury
Following dietary restrictions (e.g., ketogenic diet, intermittent fasting, low-carb diet)
Allergic or unwilling to consume the study beverages (water, artificially sweetened sports drinks, full-sugar sports drinks)
Haemophobic or averse to blood sampling

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation was concealed using sequentially numbered, sealed opaque envelopes prepared by a researcher not involved in participant recruitment or testing. The allocation schedule was generated prior to the commencement of the study using a computer-based randomisation tool. The envelopes were opened only after the participant was deemed eligible and had consented to participate
Randomisation list will be stored separately, and an independent researcher will prepare beverages in opaque bottles to ensure blinding.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A computer-generated randomisation sequence will be used to determine the order of beverage consumption for each participant.
A counterbalanced, crossover design will be implemented to minimise order effects.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
31/03/2025
Date of last participant enrolment
Anticipated
1/05/2025
Actual
Date of last data collection
Anticipated
16/05/2025
Actual
Sample size
Target
10
Accrual to date
8
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 318511 0
Self funded/Unfunded
Name [1] 318511 0
Country [1] 318511 0
Primary sponsor type
University
Name
University of Sydney
Address
Country
Australia
Secondary sponsor category [1] 321072 0
None
Name [1] 321072 0
Address [1] 321072 0
Country [1] 321072 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 317116 0
The University of Sydney Human Research Ethics Committee
Ethics committee address [1] 317116 0
Ethics committee country [1] 317116 0
Australia
Date submitted for ethics approval [1] 317116 0
11/11/2024
Approval date [1] 317116 0
12/02/2025
Ethics approval number [1] 317116 0
2024/HE001420

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 140046 0
A/Prof Kieron Rooney
Address 140046 0
University of Sydney, Susan Wakil Health Building Western Ave, Camperdown NSW 2050
Country 140046 0
Australia
Phone 140046 0
+61 402770759
Fax 140046 0
Email 140046 0
[email protected]
Contact person for public queries
Name 140047 0
Liam McQuinn
Address 140047 0
University of Sydney, Susan Wakil Health Building Western Ave, Camperdown NSW 2050
Country 140047 0
Australia
Phone 140047 0
+61 433512864
Fax 140047 0
Email 140047 0
[email protected]
Contact person for scientific queries
Name 140048 0
Liam McQuinn
Address 140048 0
University of Sydney, Susan Wakil Health Building Western Ave, Camperdown NSW 2050
Country 140048 0
Australia
Phone 140048 0
+61 433512864
Fax 140048 0
Email 140048 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
24567Ethical approvalN/A [email protected] Provided upon request Decision notification letter.pdf
24568Study protocolN/A [email protected] Provided upon request project-description-template-Final-V1.docx



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.