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Trial registered on ANZCTR
Registration number
ACTRN12616000433404
Ethics application status
Approved
Date submitted
14/03/2016
Date registered
5/04/2016
Date last updated
16/02/2017
Type of registration
Retrospectively registered
Titles & IDs
Public title
Effects of low carbohydrate availability with high protein or high fat on the response to training and performance.
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Scientific title
Effects of low carbohydrate availability with high protein or high fat intake on the response to cycling training and performance in well trained cyclists
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Secondary ID [1]
288590
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Nil known
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Universal Trial Number (UTN)
N/A
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Trial acronym
N/A
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Linked study record
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Health condition
Health condition(s) or problem(s) studied:
Metabolic response to training
297733
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Condition category
Condition code
Diet and Nutrition
297917
297917
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0
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Other diet and nutrition disorders
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Metabolic and Endocrine
297918
297918
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0
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Normal metabolism and endocrine development and function
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Intervention/exposure
Study type
Interventional
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Description of intervention(s) / exposure
Participants will complete 2 x 12 day interventions.
In both trials, participants will follow a high carbohydrate diet for 5 days and all food and drink is provided by the researchers,. During this time participants will follow their own training program. They will then enter the lab on day 5 for a short exercise test (20 min at 70% VO2max) and a blood sample via venepuncture will be collected pre and post exercise. Expired gas and rate of perceived exertion will be collected during the last 5 min of the exercise.
Participants will then enter the lab on day 6 and have their body composition measured using a DEXA scan (dual- energy x-ray absorptiometry), a muscle biopsy will be taken from the quadricep muscle by a certified doctor and an indwelling cannula will be inserted into an anticubital vein in the arm. This will allow for serial blood sample during the exercise protocol. Participants will complete 20 min of exercise at 70% VO2max followed by a high intensity interval session (8 x 5 min exercise with 1 min rests between reps). During the exercise expired gas and rate of perceived exertion will be collected at regular intervals. Participants will then start either a high fat or high protein diet for the next 5 days. During this time participants will complete prescribed training, equating to up to 300 km cycling. Following 5 days of this diet, participants enter the lab and complete another DEXA scan and have another muscle biopsy in the quadriceps and a blood sample via venepuncture (pre and post) before completing 20 min of exercise at 70% VO2max. Expired gas and rate of perceived exertion is collected during the final 5 min of exercise. Participants then follow a high carbohydrate diet for 24 h.
Following the 5 days either high fat or protein and the 1 day carbohydrate diet participants will enter the lab and have another muscle biopsy taken and an indwelling cannula will be inserted into one of the anticubital veins. Participants will also
be infused with a bolus of 0.37 MBq of U-14C-labelled glucose to measure blood glucose oxidation. Participants will then complete 100 min of cycling at 70% VO2max following by a time trial lasting approximately 30 mins. During the 100 min ride blood samples, expired gas and rate of perceived exertion will be collected every 20 min. Participants have a last biopsy following the 100 min ride.
The 12 day interventions will be separated by at least 10 days.
The composition of the diets is:
High carb diet: 75% energy, carbohydrate, 15 % energy protein, 10 % energy fat.
High fat diet: 20% energy, carbohydrate, 15 % energy protein, 65 % energy fat.
High protein diet: 20% energy, carbohydrate, 65 % energy protein, 15 % energy fat.
Participants will be closely monitored by all staff during their time in the lab. Outside the lab participants will be able to contact the dietitian regarding diet and are required to complete a daily food checklist. They can also contact the student researcher regarding any questions about the rest of the study.
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Intervention code [1]
294191
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Other interventions
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Comparator / control treatment
The participants act as their own control and the high carbohydrate diet will act as the control.
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Control group
Active
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Outcomes
Primary outcome [1]
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Substrate utilisation during prolonged, submaximal cycling using expired gas collected during exercise via a Parvomedics online gas analysis system.
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Assessment method [1]
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Timepoint [1]
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Pre to post the high fat or high protein dietary intervention- They will be compared from day 1 of the high fat or high protein diet to day 6 which is 1 day following the high fat or protein diet.
Also day 5 of the carbohydrate diet will be compared to day 7 which is the large testing day when participants cycle for 100 minutes plus complete the time trial.
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Secondary outcome [1]
321762
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Changes in mitochondrial respiration as a consequence of the dietary intervention from muscle biopsies collected.
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Assessment method [1]
321762
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Timepoint [1]
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Pre to post the high fat or high protein dietary intervention. They will be compared from day 1 of the high fat or high protein diet to day 6 which is 1 day following the high fat or protein diet and also day 7 which is the large testing day when participants cycle for 100 minutes plus complete the time trial.
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Secondary outcome [2]
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Plasma free fatty acid response
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Assessment method [2]
321763
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Timepoint [2]
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This will be measured every 20 min during the 100 min exercise trial on day 7.
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Secondary outcome [3]
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Plasma insulin response
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Assessment method [3]
321764
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Timepoint [3]
321764
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This will be measured every 20 min during the 100 min exercise trial on day 7.
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Eligibility
Key inclusion criteria
Well trained cyclists riding more than 200 km per week.
A VO2max of > 60 ml/kg/min (this is tested in the lab via a short incremental exercise test on the bike)
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Minimum age
18
Years
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Maximum age
45
Years
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Sex
Males
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Can healthy volunteers participate?
Yes
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Key exclusion criteria
Participants will only be excluded if they are unable to follow the dietary intervention due to an allergy or intolerance.
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Study design
Purpose of the study
Educational / counselling / training
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Allocation to intervention
Randomised controlled trial
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Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
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Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple block randomisation using computer generated, randomised sequence. An independent third part will prepare the computer generated order of trials and seal these in envelopes. Once informed consent is obtained, the sealed envelope will be opened by the dietitian revealing the trial order.
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Masking / blinding
Blinded (masking used)
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Who is / are masked / blinded?
The people assessing the outcomes
The people analysing the results/data
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Intervention assignment
Crossover
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Other design features
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Phase
Not Applicable
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Type of endpoint/s
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Statistical methods / analysis
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Recruitment
Recruitment status
Completed
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Date of first participant enrolment
Anticipated
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Actual
3/03/2016
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Date of last participant enrolment
Anticipated
30/06/2016
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Actual
21/04/2016
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Date of last data collection
Anticipated
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Actual
7/08/2016
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Sample size
Target
8
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Accrual to date
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Final
8
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Recruitment in Australia
Recruitment state(s)
VIC
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Recruitment postcode(s) [1]
12919
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3065 - Fitzroy
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Recruitment postcode(s) [2]
12920
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3000 - Melbourne
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Funding & Sponsors
Funding source category [1]
293113
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Other
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Name [1]
293113
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Australian Institute of Sport
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Address [1]
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Leverrier St, Bruce ACT 2617
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Country [1]
293113
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Australia
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Primary sponsor type
Individual
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Name
Professor John Hawley
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Address
Australian Catholic University
Level 1 Daniel Mannix Building
8-18 Brunswick Street
Mary MacKillop Institute for Health Research
Fitzroy, 3065.
Melbourne
Victoria
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Country
Australia
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Secondary sponsor category [1]
291903
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Individual
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Name [1]
291903
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Professor Louise Burke
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Address [1]
291903
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Australian Institute of Sport
Leverrier St, Bruce ACT 2617
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Country [1]
291903
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Australia
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Ethics approval
Ethics application status
Approved
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Ethics committee name [1]
294612
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Australian Catholic University Human Research Ethics comittee
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Ethics committee address [1]
294612
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Manager, Ethics c/o Office of the Deputy Vice Chancellor (Research) Australian Catholic University North Sydney Campus PO Box 968 North Sydney, NSW 2059
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Ethics committee country [1]
294612
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Australia
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Date submitted for ethics approval [1]
294612
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19/11/2015
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Approval date [1]
294612
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25/02/2016
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Ethics approval number [1]
294612
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2015-305H
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Summary
Brief summary
Endurance performance lasting >90 min is limited by carbohydrate stores. Therefore for the past few decades’ researchers have proposed ways to increase the use of fat as a fuel source, reducing reliance on carbohydrate sources during endurance events and ‘sparing’ muscle glycogen. Recent studies have focused on high fat, low carbohydrate diets, which have become increasingly popular amongst athletes, with the expectation of a greater response to training and improved performance. High fat, low carbohydrate diets (~ 65% energy intake from fat) for up to 2 weeks have been shown to increase the use of fat as a fuel source during low to moderate intensity cycling however an improvement in cycling performance is yet to be reported. Another nutritional strategy prescribed to increase the use of fat during training is a high protein, low carbohydrate diet, otherwise known as ‘train low’ (i.e. with low carbohydrate stores). Although both strategies increase the use of fat stores, the complex muscular responses and mechanisms behind these adaptations have yet to be reported. The aim of this study is to determine whether low carbohydrate availability in the presence of high fat or high protein is the driver of the increased fat oxidation and reduced glycogenolysis reported following a 5 day high fat diet.
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Trial website
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Trial related presentations / publications
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Public notes
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Contacts
Principal investigator
Name
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Prof John Hawley
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Address
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Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
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Country
63738
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Australia
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Phone
63738
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+61399533552
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Fax
63738
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Email
63738
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[email protected]
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Contact person for public queries
Name
63739
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Jill Leckey
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Address
63739
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Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
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Country
63739
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Australia
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Phone
63739
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+61424701433
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Fax
63739
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Email
63739
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[email protected]
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Contact person for scientific queries
Name
63740
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John Hawley
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Address
63740
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Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
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Country
63740
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Australia
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Phone
63740
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+61399533552
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Fax
63740
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Email
63740
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[email protected]
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No information has been provided regarding IPD availability
What supporting documents are/will be available?
No Supporting Document Provided
Results publications and other study-related documents
Documents added manually
No documents have been uploaded by study researchers.
Documents added automatically
Source
Title
Year of Publication
DOI
Embase
High dietary fat intake increases fat oxidation and reduces skeletal muscle mitochondrial respiration in trained humans.
2018
https://dx.doi.org/10.1096/fj.201700993R
N.B. These documents automatically identified may not have been verified by the study sponsor.
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