Trial Review

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
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.
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
Secondary ID [1] 288590 0
Nil known
Universal Trial Number (UTN)
N/A
Trial acronym
N/A
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Metabolic response to training 297733 0
Condition category
Condition code
Diet and Nutrition 297917 297917 0 0
Other diet and nutrition disorders
Metabolic and Endocrine 297918 297918 0 0
Normal metabolism and endocrine development and function

Intervention/exposure
Study type
Interventional
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.

Intervention code [1] 294191 0
Other interventions
Comparator / control treatment
The participants act as their own control and the high carbohydrate diet will act as the control.
Control group
Active

Outcomes
Primary outcome [1] 297668 0
Substrate utilisation during prolonged, submaximal cycling using expired gas collected during exercise via a Parvomedics online gas analysis system.
Timepoint [1] 297668 0
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.
Secondary outcome [1] 321762 0
Changes in mitochondrial respiration as a consequence of the dietary intervention from muscle biopsies collected.
Timepoint [1] 321762 0
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.
Secondary outcome [2] 321763 0
Plasma free fatty acid response
Timepoint [2] 321763 0
This will be measured every 20 min during the 100 min exercise trial on day 7.
Secondary outcome [3] 321764 0
Plasma insulin response
Timepoint [3] 321764 0
This will be measured every 20 min during the 100 min exercise trial on day 7.

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)
Minimum age
18 Years
Maximum age
45 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants will only be excluded if they are unable to follow the dietary intervention due to an allergy or intolerance.

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
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.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


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
Completed
Date of first participant enrolment
Anticipated
Actual
3/03/2016
Date of last participant enrolment
Anticipated
30/06/2016
Actual
21/04/2016
Date of last data collection
Anticipated
Actual
7/08/2016
Sample size
Target
8
Accrual to date
Final
8
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment postcode(s) [1] 12919 0
3065 - Fitzroy
Recruitment postcode(s) [2] 12920 0
3000 - Melbourne

Funding & Sponsors
Funding source category [1] 293113 0
Other
Name [1] 293113 0
Australian Institute of Sport
Country [1] 293113 0
Australia
Primary sponsor type
Individual
Name
Professor John Hawley
Address
Australian Catholic University
Level 1 Daniel Mannix Building
8-18 Brunswick Street
Mary MacKillop Institute for Health Research
Fitzroy, 3065.
Melbourne
Victoria
Country
Australia
Secondary sponsor category [1] 291903 0
Individual
Name [1] 291903 0
Professor Louise Burke
Address [1] 291903 0
Australian Institute of Sport
Leverrier St, Bruce ACT 2617
Country [1] 291903 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294612 0
Australian Catholic University Human Research Ethics comittee
Ethics committee address [1] 294612 0
Manager, Ethics
c/o Office of the Deputy Vice Chancellor (Research)
Australian Catholic University
North Sydney Campus
PO Box 968
North Sydney, NSW 2059
Ethics committee country [1] 294612 0
Australia
Date submitted for ethics approval [1] 294612 0
19/11/2015
Approval date [1] 294612 0
25/02/2016
Ethics approval number [1] 294612 0
2015-305H

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.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 63738 0
Prof John Hawley
Address 63738 0
Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
Country 63738 0
Australia
Phone 63738 0
+61399533552
Fax 63738 0
Email 63738 0
[email protected]
Contact person for public queries
Name 63739 0
Miss Jill Leckey
Address 63739 0
Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
Country 63739 0
Australia
Phone 63739 0
+61424701433
Fax 63739 0
Email 63739 0
[email protected]
Contact person for scientific queries
Name 63740 0
Prof John Hawley
Address 63740 0
Australian Catholic University
Level 1 Daniel Mannix Building
Australian Catholic University
8-18 Brunswick Street
Fitzroy, 3065
Melbourne
Victoria
Country 63740 0
Australia
Phone 63740 0
+61399533552
Fax 63740 0
Email 63740 0
[email protected]

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
SourceTitleYear of PublicationDOI
EmbaseHigh dietary fat intake increases fat oxidation and reduces skeletal muscle mitochondrial respiration in trained humans.2018https://dx.doi.org/10.1096/fj.201700993R
N.B. These documents automatically identified may not have been verified by the study sponsor.