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Trial registered on ANZCTR

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

Titles & IDs
Public title
Fibre, protein and insulin resistance diet study
Scientific title
A randomised, controlled dietary intervention to evaluate the effect on a high protein and high fibre diet on insulin sensitivity and markers of cardiovascular disease risk in healthy, overweight women.
Secondary ID [1] 281041 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Insulin resistance in healthy overweight women. 1654 0
Diabetes prevention in healthy overweight women. 1655 0
Metabolic syndrome in healthy overweight women. 1656 0
Condition category
Condition code
Metabolic and Endocrine 1760 1760 0 0
Diet and Nutrition 1761 1761 0 0

Study type
Description of intervention(s) / exposure
Participants will be randomised to one of 2 diets for 10 weeks. The diets will be:
1) a control diet based on best practices for nutritional counselling and the New Zealand dietary guidelines and food pyramid

Participants will be required to maintain their baseline weight for the first 4 weeks. From week 5 participants will be counselled to eat as much as required to feel satisfied while adhering to their dietary regime.

Participants will meet with a study researcher on a weekly basis for 20 minute nutritional counselling sessions and to be weighed.
Intervention code [1] 1595 0
Comparator / control treatment
2) a high protein, high fibre diet (30% protein, 25% fat, 45% carbohydrate, 35-40 g total dietary fibre).
Control group

Primary outcome [1] 2458 0
Insulin resistance measured by both a new dynamic method and Homeostasis Model Assessment for Insulin Resistance (HOMA-IR)
Timepoint [1] 2458 0
At baseline, 4 weeks and 10 weeks.
Secondary outcome [1] 4224 0
Timepoint [1] 4224 0
At baseline, 4 weeks and 10 weeks.
Secondary outcome [2] 4225 0
Fasting plasma lipids, glucose, insulin, C-Reactive protein (CRP), plasminogen activator inhibitor-1 (PAI-1), adiponectin, interleukin 6 (IL6), interleukin 18 (IL18), tumour necrosis factor alpha and grehlin; and percentage body fat mass and lean mass, and waist and hip circumference.
Timepoint [2] 4225 0
At baseline and 10 weeks

Key inclusion criteria
Overweight; BMI = 27 kg/m2 and weight < 120 kg or BMI >23 kg/m2 and a direct family history of type 2 diabetes.Normal or impaired glucose tolerance.Weight stable over last 3 months and willing to maintain weight initially.Prepared to undergo dietary intervention and eat substantial amounts of dietary fibre including wholegrains, legumes and pulses.
Minimum age
18 Years
Maximum age
65 Years
Can healthy volunteers participate?
Key exclusion criteria
No diabetes, history of cardiovascular disease, or renal or hepatic failure.Not suffering from any other major medical condition.No psychiatric illness, drug or alcohol dependence that would affect ability to adhere to the dietary guidelines.Not pregnant or lactating.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes containing treatment assignation will be prepared by a research assitant who is not involved in the study in any other way and allocation to participants in sequential order.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Individuals will be randomised to treatment groups stratified by age and BMI. Strata will be randomised in random sized blocks using the randomisation commands in Microsoft Excel.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 1
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 outside Australia
Country [1] 483 0
New Zealand
State/province [1] 483 0

Funding & Sponsors
Funding source category [1] 1913 0
Government body
Name [1] 1913 0
New Zealand Foundation of Research Sciences and Technology Project DRIX0401.
Address [1] 1913 0
Ministry of Business, Innovation & Employment (MBIE)
PO Box 5762
Wellington 6145
Country [1] 1913 0
New Zealand
Primary sponsor type
Dr Kirsten McAuley
Department of Human Nutrition
University of Otago
PO Box 56
Dunedin 9054
New Zealand
Secondary sponsor category [1] 1725 0
Name [1] 1725 0
Professor Jim Mann
Address [1] 1725 0
Departments of Human Nutrition and Medicine
University of Otago
PO Box 56
Dunedin 9054
Country [1] 1725 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 3557 0
University of Otago
Ethics committee address [1] 3557 0
Ethics committee country [1] 3557 0
New Zealand
Date submitted for ethics approval [1] 3557 0
Approval date [1] 3557 0
Ethics approval number [1] 3557 0

Brief summary
Insulin resistance (IR) is an underlying cause of most cases of type 2 diabetes. The prevalence of diagnosed diabetes in New Zealand is estimated to be 4% in the general New Zealand population and as high as 12% in Maori and Pacific Peoples. These are likely to be underestimates and the prevalence is further increased when including estimates of undiagnosed cases. Furthermore diabetes is believed to be increasing at an alarming rate in New Zealand and throughout the world. Given that IR is associated with severe health risks including obesity, high blood pressure, dyslipidaemia (abnormal blood fats), raised blood sugar and damage to blood vessels it is not surprising that insulin resistance is also associated with a significant increase in cardiovascular disease (CVD) risk in both diabetic and non-diabetic adults.

Lifestyle interventions indicate that improvements in insulin sensitivity of 20-30% may be achievable. However we currently have little indication of which dietary modifications will achieve the greatest change. This study will attempt to determine the extent to which IR and other related risk factors for cardiovascular disease can be reduced by a diet high in both dietary fibre and dietary protein, both with and without weight loss.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 27529 0
Address 27529 0
Country 27529 0
Phone 27529 0
Fax 27529 0
Email 27529 0
Contact person for public queries
Name 10784 0
Lisa Te Morenga
Address 10784 0
Department of Human Nutrition
University of Otago
PO Box 56
Country 10784 0
New Zealand
Phone 10784 0
Fax 10784 0
Email 10784 0
Contact person for scientific queries
Name 1712 0
Lisa Te Morenga
Address 1712 0
Department of Human Nutrition
University of Otago
PO Box 56
Country 1712 0
New Zealand
Phone 1712 0
Fax 1712 0
Email 1712 0

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