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Trial registered on ANZCTR


Registration number
ACTRN12616001579482
Ethics application status
Approved
Date submitted
11/11/2016
Date registered
16/11/2016
Date last updated
16/11/2016
Type of registration
Retrospectively registered

Titles & IDs
Public title
An investigation into the effect of a 12-week RCT comparing a low carbohydrate, high fat diet vs mainstream nutrition guidelines on metabolic health outcomes in overweight New Zealand Defence Force personnel.
Scientific title
Efficacy of a 12-week RCT comparing a low carbohydrate, high fat diet vs mainstream nutrition guidelines on metabolic health outcomes (body composition, lipids and glycaemic control) in a sample of 41 overweight New Zealand navy personnel.
Secondary ID [1] 290522 0
None
Universal Trial Number (UTN)
U1111-1189-7311
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Overweight / obesity 300938 0
Condition category
Condition code
Cardiovascular 300738 300738 0 0
Other cardiovascular diseases
Metabolic and Endocrine 300755 300755 0 0
Diabetes
Diet and Nutrition 300764 300764 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Title: A 12-week RCT to assess the efficacy of a low carbohydrate, high fat diet compared with mainstream nutrition guided diet (i.e. high carbohydrate, low fat) on weight loss and metabolic health outcomes (glycaemic control; lipid markers) in a group of 41 overweight New Zealand defence force personnel.

Once assessed for eligibility, participants were randomly assigned to the two dietary groups. They attended a 90 minute face-to-face workshop delivered by a Registered Nutritionist who was part of the research team) detailing the dietary approach (or both styles of eating. They were also provided with supporting resources. For the mainstream group, this included the Ministry of Health website on food & Nutrition guidelines as well as the associated hard copy guidelines booklets. The LCHF group were directed to a designated website the team created specifically for this research project as well as a hard copy booklet, again created for the purpose of this research work.

Participants were not prescribed with a personalised set of a energy and macronutrient requirements, but rather they were provided will general guidelines about concepts and foods to consume and to avoid on their respective diet. It was anticipated that the mainstream style of eating (Usual Care) reflected a macronutrient profile that aligned with the New Zealand Food & Nutrition Guidelines (i.e. Carbohydrate: 45-60% of total energy; Protein 15-25% of total energy; Fat 30-33% of total energy). It was anticipated that the LCHF style of eating reflected a carbohydrate intake approximating less than the lower range of Usual Care recommendation i.e., <45% of total energy; a higher fat intake, approximating more than 33% of total energy, and a moderate protein intake, approximating 15-25% of total energy.

A telephone support line was available throughout the 12 weeks for the participants to access should they have needed to. All measurements were conducted at the naval base during work hours. A full set of outcomes (i.e. weight, waist circumference and a blood assay to assess lipids and glycaemic control) were measured at weeks 0 (prior to the start of the intervention) and at week 12. At weeks 4 and 8, a weight and waist measure were recorded for monitoring and support purposes. To assess adherence, participants were asked to complete a 4-day food diary to be discussed at these meetings for discussion. At the meetings themselves, they were asked to rate their level of adherence on a 10-point scale. This was used as a monitoring and discussion point at these sessions. During this time, participants had the opportunity to discuss their progress or queries they have with the team.
Intervention code [1] 296371 0
Lifestyle
Intervention code [2] 296384 0
Treatment: Other
Comparator / control treatment
The control group was considered "Usual care" for weight loss. i.e., participants were provided with nutrition guidelines that align with 'best practice" mainstream Ministry of Health guidelines for weight loss. This reflects a way of eating that is moderate-to-high in carbohydrate and low in fat and that incorporates the specific principles of calorie reduction through portion control.). It was anticipated that this style of eating reflected a macronutrient profile that aligned with the New Zealand Food & Nutrition Guidelines (i.e. Carbohydrate: 45-60% of total energy; Protein 15-25% of total energy; Fat 30-33% of total energy).
Control group
Active

Outcomes
Primary outcome [1] 300154 0
Weight loss
Timepoint [1] 300154 0
Weeks 0, 4, 8, and 12
Secondary outcome [1] 329198 0
Glycaemic control as determined by venepuncture technique using laboratory serum assays.
Timepoint [1] 329198 0
Weeks 0, 12
Secondary outcome [2] 329200 0
Lipid profile as determined by venepuncture technique using laboratory serum assays.
Timepoint [2] 329200 0
Weeks 0, 12
Secondary outcome [3] 329276 0
Waist circumference
Timepoint [3] 329276 0
Weeks 0, 4, 8, 12

Eligibility
Key inclusion criteria
All participants were NZ navy personnel.

All participants needed to have a BMI>25

Participants had to have been consuming a diet that contained 250g or more of carbohydrate (was assessed via screening).
Minimum age
18 Years
Maximum age
60 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
All participants with a BMI<25

Participants were to be consuming a diet that contained less than 250g carbohydrate (to be assessed via screening).

Participants that were on a "weight-loss" diet at the time.

Pregnant or breastfeeding females.


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)
Central randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table from a statistic book
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
The sample size calculation was conducted using a statistical package called G*Force. The size of the sample to provide 80% power to detect a difference of 5kg of weight loss between the low carbohydrate, high fat and the usual care groups at a 2-sided a level of significance of 5%, was estimated to be 40.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 8386 0
New Zealand
State/province [1] 8386 0
Auckland

Funding & Sponsors
Funding source category [1] 294938 0
University
Name [1] 294938 0
Auckland University of Technology
Address [1] 294938 0
AUT
Private Bag 92006,
Northcote, 1020
Auckland
Country [1] 294938 0
New Zealand
Primary sponsor type
University
Name
AUT
Address
AUT
Private Bag 92006,
Northcote, 1020
Auckland
Country
New Zealand
Secondary sponsor category [1] 293768 0
Government body
Name [1] 293768 0
New Zealand Defence Force
Address [1] 293768 0
NZ Navy
Private Bag 39995
Wellington Mail Centre
Wellington 5045
Country [1] 293768 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296309 0
AUT Ethics Committee (AUTEC)
Ethics committee address [1] 296309 0
AUTEC
WA 505D Level 5 Building WA City Campus,
Private Bag 92006 Auckland 1142, Auckland New Zealand.
Ethics committee country [1] 296309 0
New Zealand
Date submitted for ethics approval [1] 296309 0
Approval date [1] 296309 0
20/08/2014
Ethics approval number [1] 296309 0
14/246.

Summary
Brief summary
This study involved a 12-week dietary intervention comparing a low carbohydrate, high fat (LCHF) way of eating alongside against a control mainstream-nutrition-guided group in a group of navy personnel from the New Zealand Defence Force ( NZDF). The immediate aim of the study was to assess the effects of LCHF with mainstream nutrition advice on weight loss and metabolic health of at-risk personnel. The desired longer term aims were to improve the long-term health and wellbeing risk profile of at-risk individuals, to help reduce the number of personnel unfit for operational service, and to reverse the growing proportion of overweight and obese individuals both within NZDF and the general New Zealand population.
Trial website
http://www.lchf.co.nz/background-navy/
Trial related presentations / publications
Williden, M., Zinn, C., McPhee., Harris, Prendergast, K., Kilding, H., & Schofield, G. Improving the health of the New Zealand Defence Force: A whole-food, lower carbohydrate approach. Poster presentation at Ancestral Health Symposium 2016, Boulder, Colorado.
Public notes

Contacts
Principal investigator
Name 70394 0
Dr Caryn Zinn
Address 70394 0
AUT
Private Bag 92006
Northcote 1020 Auckland
Country 70394 0
New Zealand
Phone 70394 0
+64 09 921 9999 ext 7842
Fax 70394 0
Email 70394 0
caryn.zinn@aut.ac.nz
Contact person for public queries
Name 70395 0
Dr Caryn Zinn
Address 70395 0
AUT
Private Bag 92006
Northcote 1020 Auckland
Country 70395 0
New Zealand
Phone 70395 0
+64 09 921 9999 ext 7842
Fax 70395 0
Email 70395 0
caryn.zinn@aut.ac.nz
Contact person for scientific queries
Name 70396 0
Dr Caryn Zinn
Address 70396 0
AUT
Private Bag 92006
Northcote 1020 Auckland
Country 70396 0
New Zealand
Phone 70396 0
+64 09 921 9999 ext 7842
Fax 70396 0
Email 70396 0
caryn.zinn@aut.ac.nz

No information has been provided regarding IPD availability
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