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Trial registered on ANZCTR


Registration number
ACTRN12618000035224
Ethics application status
Approved
Date submitted
14/12/2017
Date registered
12/01/2018
Date last updated
12/01/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
Keto-lifting: the effect of a ketogenic diet on strength performance
Scientific title
The effect of a ketogenic diet on body composition and strength performance in Olympic weighting and Powerlifting athletes: a 6-month randomised controlled, crossover trial
Secondary ID [1] 293601 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Body Composition 305861 0
Condition category
Condition code
Diet and Nutrition 305064 305064 0 0
Other diet and nutrition disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants were aged between 20 – 60 years, had at least 6-months experience in Powerlifting / Weightlifting / Crossfit and were free of limiting musculoskeletal injuries at the time of recruitment. Body composition, strength and power, blood analysis and resting metabolic rate were measured at baseline testing. This crossover study design randomly allocated participants to commence the study with either their usual control diet (>250g daily intake of carbohydrates) or a Ketogenic diet (<10% daily intake of carbohydrates) for 3-months. All measures were re-tested after 3-months, and a 2-week ‘washout’ period was imposed where participants were instructed to halve their exercise intensity and volume and continue (or return) to their usual diet. Participants then crossed over to the alternate intervention diet for a period of 3-months, followed by the final data collection. All participants were advised to consume ad libitum and to use kitchen scales to measure food portions.

Testing Procedures
Baseline, mid and final testing sessions were conducted at Australian Catholic University, Strathfield campus. Measurements were obtained following a 12-hour fast, requiring participants to refrain from consuming any food or beverages, including stimulants such as coffee, for at least 12 hours prior. Participants were instructed not to perform any exercise on the morning of testing. Testing sessions were conducted by accredited exercise scientists.

Body composition: Body fat and lean tissue mass were measured by dual-energy X-ray absorptiometry (Medilink Medix DR, 2D-Fan beam, Montpellier, France) from a whole body scan. Measurements were performed at the predetermined scan mode (speed 180 mm/s, resolution 2mm x 2mm, 256 Channel Digital Detector: 72mm x 8mm Collimation) with the analysis software provided by the manufacturer (Medilink – Eazix Software). Participants were required to wear light clothing without zippers or buttons and removed all jewellery for the scanning procedures. The same technologist conducted and analyse all DXA scans.

Strength and power assessment: Participants were assessed in the squat, bench press and deadlift exercises or equivalent exercises relevant to their sport (eg: snatch, clean and jerk). Participants were provided with a light warm-up period (2 – 3 minutes walking on a treadmill or stationary bicycle at a self-selected speed). The 1RM protocol commenced with one set of 10 repetitions at approximately 50% of a participant’s known previous maximum strength. Participants then increased resistance over 3 – 6 attempts to reach 1RM with a rest period of 2 mins between sets. The weight lifted for 1RM was recorded when a participant fully executes an exercise correctly with maximal effort. Participants were provided with 20 minutes rest between exercises.

Electrolyte balance and blood glucose: Electrolyte balance (Sodium, Potassium and Chloride) and blood glucose were obtained from finger-prick blood samples and measured using a hand-held analyser (iSTAT handheld portable blood analyser, Abbott).

Resting metabolic rate: Resting metabolic rate (RMR) was determined using indirect calorimetry (analysis of expired air to determine oxygen consumption and carbon dioxide production). Participants attended the laboratory to undertake RMR testing. The gold standard RMR method was used and involved resting subjects lying supine with a canopy installed over their head. The canopy is designed to regulate air in and out while permitting gas analysis of expired air. Food, ethanol, caffeine, and nicotine affect RMR and their consumption before each test was controlled. Physical activity prior to RMR testing was also controlled. Measurements were approximately 15 minutes in duration with the first 5 minutes deleted and the remaining 10 minutes having a coefficient of variation <10% to be considered valid.

Self-reported measures: Throughout each 3-month period, participants were required to record self-reported information about their food/fluid intake, blood glucose/ketone and training data. Participants were instructed on how on to perform these measures at baseline testing sessions. These measures were required 3 times per week but only every 4 weeks. Self-reported measures were collected using online survey software (Qualtrics, Provo, Utah, USA). Access to the online survey were distributed to each participant via email.

Macronutrient Composition: Participants were instructed to record their daily food and fluid intake using a smartphone app (MyFitnessPal). Prior to the commencement of the Ketogenic diet intervention, participants received education about what foods were suitable via a list of foods categorised as “green”, “orange” or “red”. During the ketogenic diet, participants were encouraged to eat ad libitum from the green list. The orange list contained foods that can be occasionally consumed and included suggested quantity limits. The red list contained foods that should be avoided in order to maintain nutritional ketosis. Each participant received 30mins of face-to-face education at baseline testing with the primary investigator. Participants were also invited to join an online private social media group to relay instructional videos and menu plans and facilitate on-going communication between participants and the research team. The primary researcher had secure access to user accounts and provided feedback on adherence to the prescribed dietary interventions.

Blood ketones and glucose: Participants were instructed on how to self-measure their blood ketones and glucose. Participants were provided with a monitoring kit (Freestyle Optium Neo) which contained a monitor, test strips, alcohol swabs, lancets, a sharps container and latex glove (optional). The test involved one finger prick to obtain a drop of blood for analysis and results were provided within 5 seconds.

Training data: Participants recorded information about the number of weekly training sessions, average session length and percent contributions of aerobic exercise, strength training and pre-hab/rehabilitation. Average sessional intensity was also reported, using a 10-point scale.
Intervention code [1] 299860 0
Treatment: Other
Intervention code [2] 299935 0
Lifestyle
Comparator / control treatment
Participants served as their own control, e.g., their usual diet (>250g daily intake of carbohydrates), as this study was a cross-over design.
Control group
Active

Outcomes
Primary outcome [1] 304234 0
Body composition (Body fat and lean tissue mass) measured by dual-energy X-ray absorptiometry (Medilink Medix DR, 2D-Fan beam, Montpellier, France) from a whole body scan.
Timepoint [1] 304234 0
Baseline, after 3 months (mid) and after another 3 months (primary endpoint).
Primary outcome [2] 304235 0
Maximal strength/power measured by 1 rep maximum (1RM) strength test, measured in Kilograms. Participants were assessed in the squat, bench press and deadlift exercises or equivalent exercises relevant to their sport (eg: snatch, clean and jerk).
Timepoint [2] 304235 0
Baseline, after 3 months (mid) and after another 3 months (primary endpoint).
Secondary outcome [1] 341325 0
Energy expenditure via measurement of resting metabolic rate (RMR), estimated by indirect calorimetry using breath-by-breath gas analysis with a ventilated hood canopy (QUARK CPET, COSMED, Rome, Italy).
Timepoint [1] 341325 0
Baseline, after 3 months (mid) and after another 3 months (final).
Secondary outcome [2] 341326 0
Respiratory quotient estimated by indirect calorimetry using breath-by-breath gas analysis with a ventilated hood canopy (QUARK CPET, COSMED, Rome, Italy).
Timepoint [2] 341326 0
Baseline, after 3 months (mid) and after another 3 months (final).
Secondary outcome [3] 341327 0
Blood analysis (composite). Blood glucose, sodium, potassium and chloride measured from finger-prick blood samples (I-STAT Chem 8+ cartridge and I-STAT1-300, Abbott Australasia)
Timepoint [3] 341327 0
Baseline, after 3 months (mid) and after another 3 months (final).

Eligibility
Key inclusion criteria
-Minimum 6 months lifting experience
-Free from musculoskeletal injuries
Minimum age
20 Years
Maximum age
60 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
-Novice lifters

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)
Sealed, opaque sequentially numbered envelopes.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer generation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
All statistical analysis was performed using IBM SPSS Statistics (V.24.0 for Windows). A priori power analyses using G*Power (V.3.1.9.1) indicated that a total sample size of 12 participants would be required to detect large effects (d=.8) with power (1 - ß) set at 0.80 and a = 0.5 using repeated measures, within factors ANOVA. All data were checked for normal distribution and outliers at each time point by Shapiro-Wilk tests (p > 0.05) and boxplots, respectively. Descriptive continuous data as mean ± SD with paired-sample t-tests were used to explore differences between groups. A one-way repeated measures ANOVA was used to determine whether there was a significant difference in primary outcome variables: (i) body mass, (ii) fat mass, (iii) lean mass (iv) 1RM strength performance and secondary outcomes: (i) resting metabolic rate and (ii) respiratory quotient over 3 time points (baseline, mid, and final) for treatment and control conditions. The assumption of sphericity was assessed by Mauchly's test of sphericity and post hoc analyses with Bonferroni adjustment were conducted on significant main effects. A p-value <0.05 was considered statistically significant and partial-eta was used to report effect size with .01 considered small, .06 medium, and .14 large effects.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
28/10/2016
Date of last participant enrolment
Anticipated
Actual
22/01/2017
Date of last data collection
Anticipated
Actual
11/08/2017
Sample size
Target
18
Accrual to date
Final
14
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 298218 0
University
Name [1] 298218 0
Australian Catholic University
Country [1] 298218 0
Australia
Primary sponsor type
University
Name
Australian Catholic University
Address
163-167 Albert Road, Strathfield, NSW, 2135
Country
Australia
Secondary sponsor category [1] 297324 0
None
Name [1] 297324 0
Address [1] 297324 0
Country [1] 297324 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 299226 0
Australian Catholic University Human Research Ethics Committee
Ethics committee address [1] 299226 0
Ethics committee country [1] 299226 0
Australia
Date submitted for ethics approval [1] 299226 0
23/03/2016
Approval date [1] 299226 0
04/08/2016
Ethics approval number [1] 299226 0
2016-76H

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

Contacts
Principal investigator
Name 79722 0
A/Prof David Greene
Address 79722 0
Australian Catholic University,
School of Exercise Science
Locked Bag 2002
Strathfield NSW 2135
Country 79722 0
Australia
Phone 79722 0
+61 2 9701 4377
Fax 79722 0
Email 79722 0
[email protected]
Contact person for public queries
Name 79723 0
David Greene
Address 79723 0
Australian Catholic University,
School of Exercise Science
Locked Bag 2002
Strathfield NSW 2135
Country 79723 0
Australia
Phone 79723 0
+61 2 9701 4377
Fax 79723 0
Email 79723 0
[email protected]
Contact person for scientific queries
Name 79724 0
David Greene
Address 79724 0
Australian Catholic University,
School of Exercise Science
Locked Bag 2002
Strathfield NSW 2135
Country 79724 0
Australia
Phone 79724 0
+61 2 9701 4377
Fax 79724 0
Email 79724 0
[email protected]

No information has been provided regarding IPD availability


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No Supporting Document Provided



Results publications and other study-related documents

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