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Trial registered on ANZCTR


Registration number
ACTRN12614001041640
Ethics application status
Approved
Date submitted
27/08/2014
Date registered
26/09/2014
Date last updated
26/11/2019
Date data sharing statement initially provided
26/11/2019
Date results information initially provided
26/11/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effect of week-on, week-off energy restricted diet on weight loss in overweight and obese women and men
Scientific title
The effect of week-on, week-off energy restricted diet compared to continuous energy restricted diet on weight loss in overweight and obese women and men
Secondary ID [1] 285242 0
nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Overweight 292877 0
Obesity 292878 0
Condition category
Condition code
Diet and Nutrition 293171 293171 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
In a randomized parallel study, adult overweight and obese women and men will undergo either a continuous energy restricted diet (CON) of 4200 kJ / day for women and 5500 kJ / day for men, a week-on, week-off energy restriction (IER), or the 5:2 dieting regime (5 days of habitual eating with 2 days per week of a very low kilojoule diet. 2100kJ for women and 2500kJ for men). The initial weight loss period will be 8 weeks for continuous dieting (CON) or 16 weeks of dieting week-on, week-off (IER) & the 5:2 group. In the initial weight loss period participants will visit the University Clinic every 2 weeks for the CON group and every 4 weeks for the IER & 5:2 group, to be weighed and have the energy restriction reinforced. These visits will be of 20 minutes duration. The weight loss program will be administered by a dietitian, participants will be given dietary advice and a diet booklet in a one-on-one consultation. There will be a single 1 hour session at baseline. Compliance to diet will be assessed using 3 day diet diaries completed weekly in CON and 2 weekly in IER. Participants will be advised to increase the number of steps/day to 10000 and provided with a pedometer.

After the initial weight loss period of 8 weeks CON and 16 weeks IER & participants will continue the same strategy on an energy restricted diet of approximately 6 MJ /day for women and 7 MJ / day for men. The 5:2 participants will remain on the same kJ intake. Participants will continue on this diet for the remaining study period 44 weeks for the continuous group and 36 weeks for the intermittent groups. Participants will be invited to attend the University clinic at 3 monthly intervals during this period to be weighed and return one 3 day diet record/month.

Participants from all groups will then also be followed up at 24mnths from the baseline visit.
Intervention code [1] 290120 0
Lifestyle
Intervention code [2] 290176 0
Behaviour
Comparator / control treatment
Week-on, week-off dieting will be compared to continuous dieting
Control group
Active

Outcomes
Primary outcome [1] 293030 0
Weight loss which will be measured using digital weighing scales
Timepoint [1] 293030 0
0, 2, 4, 6 and 8 weeks for continuous dieting and 0, 4, 8, 12 and 16 weeks for the intermittent week-on, week-off & 5:2 dieting. Participants all groups will be seen at 6, 9, 12, and 24mnths months after completion of initial weight loss period.
Secondary outcome [1] 310211 0
Change in lean and fat mass assessed by dual energy x-ray absorptiometry (DEXA) scan.
Timepoint [1] 310211 0
Change in lean and fat mass assessed by dual energy x-ray absorptiometry (DEXA) scan at 0, 8 weeks, 12 & 24mnths months for the continuous group and 0, 16 weeks, 12 & 24 months for the intermittent groups.
Secondary outcome [2] 310321 0
Change in lipids assessed by biochemical analysis
Timepoint [2] 310321 0
Change in lipids assessed by biochemical analysis at 0, 8 weeks, 12 and 24 months for the continuous group and 0, 16 weeks, 12 and 24 months for the intermittent group.
Secondary outcome [3] 310666 0
Change in glucose assessed by biochemical analysis
Timepoint [3] 310666 0
Change in glucose assessed by biochemical analysis at 0, 8 weeks, 12 and 24 months for the continuous group and 0, 16 weeks, 12 and 24 months for the intermittent groups.
Secondary outcome [4] 339691 0
Change in fibroblast growth factor 21 (FGF-21) measured via plasma assay. This outcome was added in after the first 120 participants had been recruited. However, as blood samples are not analysed until all individuals have completed the trial, all participants recruited will have this outcome measured.
Timepoint [4] 339691 0
Change in fibroblast growth factor 21 (FGF-21) assessed by biochemical analysis at 0, 8 weeks, 12 and 24 months for the continuous group and 0, 16 weeks, 12 and 24 months for the intermittent groups.

Eligibility
Key inclusion criteria
Adults 18 years old or older
BMI at or above 27 kg/m2
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
EXCLUSION CRITERIA:
Previous surgery for weight reduction.
Drinking more than 5 standard drinks per day and unable/unwilling to decrease.
Participants with Type 2 Diabetes treated with other than diet or diet and metformin.
Women who are or wish to become pregnant.
Women who are breast feeding.
Participant reports they are unwell Participating in any ongoing dietary studies.

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)
Volunteers will be stratified according to sex, age and BMI and allocated a treatment using random number. Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software
http://www.randomizer.org/
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

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 in Australia
Recruitment state(s)
SA
Recruitment postcode(s) [1] 8646 0
5001 - Adelaide

Funding & Sponsors
Funding source category [1] 289860 0
University
Name [1] 289860 0
University of South Australia
Address [1] 289860 0
GPO Box 2471
Adelaide, South Australia 5001
Australia
Country [1] 289860 0
Australia
Primary sponsor type
University
Name
University of South Australia
Address
GPO Box 2471
Adelaide, South Australia 5001
Australia
Country
Australia
Secondary sponsor category [1] 288542 0
None
Name [1] 288542 0
Address [1] 288542 0
Country [1] 288542 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 291584 0
the University of South Australia's Human Research Ethics Committee
Ethics committee address [1] 291584 0
University of South Australia
GPO Box 2471
Adelaide, South Australia 5001
Australia
Ethics committee country [1] 291584 0
Australia
Date submitted for ethics approval [1] 291584 0
29/05/2014
Approval date [1] 291584 0
15/07/2014
Ethics approval number [1] 291584 0
0000031828

Summary
Brief summary
The purpose of this study is to investigate the effect of intermittent dieting compared to continuous dieting on weight loss after an intensive weight loss period, This period will last for 8 weeks for the continuous group and 16 weeks for the intermittent groups; “week-on, week-off” strategy and the 5:2 strategy. We will also look at the effects on weight loss maintenance after 12 months. Another aim is to look at changes in muscle mass, blood lipids and glucose.
We hypothesize that those on the intermittent energy restriction patterns will achieve comparable weight loss maintenance at 12 months compared to those on the continuous energy restriction pattern.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 39346 0
A/Prof Jennifer Keogh
Address 39346 0
University of South Australia
GPO Box 2471
Adelaide, South Australia 5001
Australia
Country 39346 0
Australia
Phone 39346 0
+61 8 830 22579
Fax 39346 0
Email 39346 0
Jennifer.keogh@unisa.edu.au
Contact person for public queries
Name 39347 0
A/Prof Jennifer Keogh
Address 39347 0
University of South Australia
GPO Box 2471
Adelaide, South Australia 5001
Australia
Country 39347 0
Australia
Phone 39347 0
+61 8 830 21025
Fax 39347 0
Email 39347 0
jennifer.keogh@unisa.edu.au
Contact person for scientific queries
Name 39348 0
A/Prof Jennifer Keogh
Address 39348 0
University of South Australia
GPO Box 2471
Adelaide, South Australia 5001
Australia
Country 39348 0
Australia
Phone 39348 0
+61 8 830 21025
Fax 39348 0
Email 39348 0
Jennifer.keogh@unisa.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
IPD data will not be provided as this has not been approved by Ethics.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Yes
Journal publication details
Publication date and citation/details [1] 5867 0
Headland, M.L., Clifton, P.M. & Keogh, J.B. Effect of intermittent compared to continuous energy restriction on weight loss and weight maintenance after 12 months in healthy overweight or obese adults. Int J Obes 43, 2028–2036 (2019) doi:10.1038/s41366-018-0247-2
Attachments [1] 5867 0
Other publications
Have study results been made publicly available in another format?
No
Results – plain English summary
For the 146 individuals who completed the study (124 female, 22 male, mean BMI 33 kg/m 2) mean weight loss, and body fat loss at 12 months was similar in the three intervention groups,-6.6 kg for CER,-5.1 kg for the week-on, week-off and -5.0 kg for 5: 2. HDL-cholesterol rose (7%) and triglycerides decreased (13%) at 12 months with no differences between groups. No changes were seen for fasting glucose or LDL-cholesterol.