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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Microbiome in highly trained athletes and response to dietary change
Scientific title
Microbiome in highly trained athletes and response to dietary change
Secondary ID [1] 295915 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gut microbiome community profiling 309403 0
Condition category
Condition code
Diet and Nutrition 308250 308250 0 0
Other diet and nutrition disorders
Oral and Gastrointestinal 308251 308251 0 0
Normal oral and gastrointestinal development and function

Study type
Description of intervention(s) / exposure
21 d physical training intervention where participants will receive one of three separate dietary interventions, involving: 1) High carbohydrate availability ~ 65% carbohydrate, 15% protein, 20% fat; 2) High-fat low carbohydrate diet (LCHF) : 70-80% fat, 15-25% protein, <50g/d CHO; or 3) Periodised diet, involving the same macronutrient composition as the HCHO diet (~ 65% carbohydrate, 15% protein, 20% fat) that will involve a careful integration of sessions with high CHO availability (high muscle glycogen, CHO feeding during session), low CHO availability (low pre-exercise glycogen or overnight fasted or delayed refuelling) and well-timed protein intake (post exercise and around meal times).
The physical training involves a 21 d training program, including endurance sessions, interval training, sustained high-intensity sessions, resistance training and a weekly performance monitoring session. Training sessions will be undertaken as a group and will be monitored by the research team as well as recorded by the participants in a daily online log. The template for the weekly training programme has been developed in collaboration with a world-class race walker and several coaches to blend the typical intensified training practices of competitive race walkers with opportunities to implement the desired dietary intervention. The weekly training program will involve six mandatory sessions (key sessions include: Monday - high intensity interval session, 10 x 1 km repititions on 6 mins; Wednesday and Saturday - long walk, =<40 km; Friday - Hill session, 16 km) conducted under standardised conditions with external monitoring, while the remaining sessions will be undertaken according to the preference of individuals and noted in the participants training log. As such, sessions will be completed under instruction of the head coach, to achieve the intended training outcome and confirmed by physiological monitoring by the research team.
Adherence to the dietary intervention - All foods and fluids consumed will be provided by the research team and recorded. Menu construction and the preparation of meals/snacks will be undertaken by professional chefs, food service dietitians and sports dietitians. Meal plans will be individually developed for each athlete to integrate personal food preferences and nutrition requirements within the allocated dietary treatment. Meals will be eaten in a separate dining area in a group setting with individual meals being served for each athlete and according to their meal plans. During each meal service, the weight of each food item will be recorded using calibrated scales (accurate to 2 g). Individualised snacks will be provided for intake between meals and before or during training sessions, with the requirement for their consumption to be cross-checked at the next meal. A range of 'free foods and drinks' (foods with low energy) will be provided in the participants living area with a check list to allow each participant to report on their daily intake at the first meal of the following day. Nutrition support during longer training sessions and after key training sessions will be provided at the training site by members of the research team and intake will be recorded. Compliance to the dietary prescription and reporting requirements will be checked on a daily basis. Substitutions of foods will be considered if individuals cannot consume the volume of foods prescribed with alternatives to achieve macronutrient targets.
Intervention code [1] 312241 0
Comparator / control treatment
Parallel group design, non-placebo controlled. Due to the inability to blind entire diet, each group will be educated about the potential benefits of their intervention so that participants in each group feel they are receiving a positive dietary intervention.
Control group

Primary outcome [1] 307226 0
The effects of the dietary pattern during intensified training on the stool microbiomes of elite race walkers. Outcome assessed via 16S rRNA sequencing of the stool samples collected at baseline and post dietary interventions. (In detail, DNA extraction from stool samples, then 16S rRNA library preparation and sequencing, followed by bioinformatics analysis).
Timepoint [1] 307226 0
Pre and post 21 d dietary intervention.
Secondary outcome [1] 351172 0
The effects of the dietary pattern during intensified training on the oral microbiomes of elite race walkers. Outcome assessed via 16S rRNA sequencing of the oral saliva samples collected at baseline and post dietary interventions. (In detail, DNA extraction from oral saliva samples, then 16S rRNA library preparation and sequencing, followed by bioinformatics analysis).
Timepoint [1] 351172 0
Both baseline saliva samples and post-intervention samples were used to study the shifts in oral microbiome following dietary interventions.

Key inclusion criteria
Participants in the training study 'Dietary Periodisation to support training outcomes in elite distance athletes'
Minimum age
18 Years
Maximum age
35 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
None known, apart for unease with collection of faecal samples

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
The study intervention involved three different approaches to dietary support for the intensified training programme: high CHO availability (HCHO), periodised CHO availability (PCHO) and low CHO, high fat (LCHF). Our goal was to ensure that participants perceived they would receive benefits for their race preparation, while matching groups for key characteristics (age, current aerobic capacity, personal best times for the 20 km race walk event and training history and intended training load). Given the potential for a placebo effect, the departure of at least one of the treatments from current sports nutrition guidelines and the pragmatism required to work with world class athletes in preparation for key events, we devised a method for allocating participants to the treatments in this study. Prior to their arrival to the study camps, participants were educated about the benefits and limitations of the different dietary treatments and asked to nominate their preference(s) for, or non-acceptance of, each of these interventions. We were able to allocate the race walkers to a preferred treatment for each of the study camps, including the preferred order of treatment for those who participated in two camps, while achieving suitable matching of groups based on age, body mass, aerobic capacity and personal best for the 20 km race walking event, and matching of diet allocations between the two camps. Residual differences between groups and camps, and the involvement of both single and dual participation were included in the statistical analyses.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment outside Australia
Country [1] 20804 0
New Zealand
State/province [1] 20804 0
Country [2] 20805 0
State/province [2] 20805 0
Country [3] 20806 0
State/province [3] 20806 0
Country [4] 20807 0
State/province [4] 20807 0
Country [5] 20808 0
State/province [5] 20808 0
Country [6] 20809 0
State/province [6] 20809 0
Country [7] 20810 0
State/province [7] 20810 0

Funding & Sponsors
Funding source category [1] 300513 0
Name [1] 300513 0
Bond University
Address [1] 300513 0
14 University Drive
Queensland 4226 Australia
Country [1] 300513 0
Primary sponsor type
Government body
Australian Institute of Sport
Leverrier Cres
Australian Capital Territory, 2617 AUSTRALIA
Secondary sponsor category [1] 299987 0
Name [1] 299987 0
Australian Catholic University
Address [1] 299987 0
115 Victoria Parade
Fitzroy Victoria 3065
Country [1] 299987 0

Ethics approval
Ethics application status
Ethics committee name [1] 301303 0
Australian Institute of Sport Human Research Ethics Committee
Ethics committee address [1] 301303 0
Leverrier Cres
Bruce, ACT 2617
Ethics committee country [1] 301303 0
Date submitted for ethics approval [1] 301303 0
Approval date [1] 301303 0
Ethics approval number [1] 301303 0

Brief summary
This study will profile the gut and the oral microbiome of highly trained athletes before and after a 21-d block of intensified training to determine if changes in the community profile occur with highly controlled exposure to three different training diets (high-carbohydrate [CHO], high-fat low-CHO, and a periodised diet combining high- and low-CHO). The aim of this study is to profile the normal gut and oral microbiome of highly-trained athletes and determine if changes in diet result in concomitant change in gut microbiome community in this population, dependant on the type of diet followed. We hypothesise that the change in dietary pattern along with intensified training will have a pronounced impact on the oral and stool microbial communities.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 86562 0
Prof Louise Mary Burke
Address 86562 0
AIS Sports Nutrition
Leverrier Crescent
Bruce ACT 2617
Country 86562 0
Phone 86562 0
+61 (0) 2 6214 1351
Fax 86562 0
Email 86562 0
Contact person for public queries
Name 86563 0
Prof Louise Mary Burke
Address 86563 0
AIS Sports Nutrition
Leverrier Crescent
Bruce ACT 2617
Country 86563 0
Phone 86563 0
+61 (0) 2 6214 1351
Fax 86563 0
Email 86563 0
Contact person for scientific queries
Name 86564 0
Prof Louise Mary Burke
Address 86564 0
AIS Sports Nutrition
Leverrier Crescent
Bruce ACT 2617
Country 86564 0
Phone 86564 0
+61 (0) 2 6214 1351
Fax 86564 0
Email 86564 0

No data has been provided for results reporting
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary