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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
The effects of intermittent dieting on weight loss in overweight and obese females
Scientific title
The effect of intermittent energy restriction compared to continuous energy restriction on weight loss in healthy overweight to obese females
Secondary ID [1] 279910 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
overweight 285820 0
Obesity 285850 0
Condition category
Condition code
Diet and Nutrition 285998 285998 0 0

Study type
Description of intervention(s) / exposure
Volunteers will be assigned to one of two groups for an 8-week study. One group will diet continuously while the other will diet intermittently: 1 week dieting with an energy intake of no more than 5.5Mj, 1 week not dieting (no energy restriction), throughout the 8 weeks. Instruction in how to achieve the energy level of 5.5 MJ will be given at the beginning of the study and dietary advise will be given at every other week for 8 weeks. The continuous dieting group will be instructed in how to achieve the 5.5MJ and reinforcement will be given at fortnightly visits for 8 weeks. A food frequency questionnaire will be completed and dietary education will be delivered in a group session at UniSA at the beginning of the study and each volunteer will be weighed and measured privately every two weeks. The first visit will take approximately an hour; follow up visits will be shorter. A 1-year follow up visit will also be held to assess the long term effect.
Intervention code [1] 284235 0
Treatment: Other
Intervention code [2] 284266 0
Intervention code [3] 284267 0
Comparator / control treatment
The level of energy restricted diet will give 5500 kJ/day. “Total Wellbeing Diet” book will be used.
The volunteers will be instructed to consume a 5.5MJ diet for the duration of the study in the continuous energy restricted group. In the intermittent energy restricted group volunteers will be instructed in consuming a 5.5MJ diet in alternate weeks, starting the week of commencement. In the following week the volunteers will consume their usual diet.
The TWD book will be given to all volunteers. The “system” will be explained and example diet plan handed out.
Control group

Primary outcome [1] 286488 0
Weight loss will be assessed using digital weighting scales
Timepoint [1] 286488 0
eight weeks and 12 months
Secondary outcome [1] 296002 0
Waist to hip circumference
Timepoint [1] 296002 0
baseline eight weeks and 12 months

Key inclusion criteria
Women over age 18
Body mass index (BMI) >27 kg/m2
No concomitant serious illness
Minimum age
18 Years
Maximum age
75 Years
Can healthy volunteers participate?
Key exclusion criteria
Exclusion: Previous surgery for weight reduction
Pregnant or breast feeding women
Alcohol intake in excess of 5 standard drinks per day
Participation in other ongoing trials aiming at altering energy or macronutrient intake

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be divided into groups according to BMI and age.

Participants will be randomized using the minimization method, sealed envolopes containing the diet allocation will be used
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Dynamic randomization using minimization
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
To show if intermittent dieting is as or more effective in producing weight loss compared to continuous dieting
Not Applicable
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 in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 284689 0
Name [1] 284689 0
University of South Australia, School of Pharmacy and Medical Sciences
Address [1] 284689 0
GPO Box 2471, Adelaide, SA 5001
Country [1] 284689 0
Primary sponsor type
University of South Australia
GPO BOX 2471, Adelaide SA 5001
Secondary sponsor category [1] 283616 0
Name [1] 283616 0
Address [1] 283616 0
Country [1] 283616 0

Ethics approval
Ethics application status
Ethics committee name [1] 286683 0
Human Ethics Commitee of University of South Australia
Ethics committee address [1] 286683 0
University of South Australia, GPO Box 2471, Adelaide SA 5001
Ethics committee country [1] 286683 0
Date submitted for ethics approval [1] 286683 0
Approval date [1] 286683 0
Ethics approval number [1] 286683 0

Brief summary
Overweight and obesity is a major health problem increasing the risk of several lifestyle diseases including type 2 diabetes, cardiovascular disease and certain forms of cancers and effective strategies for weight loss are needed. A number of studies have shown equal effect on weight loss when using intermittent fasting (fasting 24h followed by 24h ad libitum eating) vs. continuous dieting. Preliminary data has suggested that an intermittent diet strategy using an energy restricted diet, in line with the continuous diet, instead of fasting produces greater weight loss compared to continuous dieting; but this has been investigated only in men. This research will look into the effect of intermittent dieting vs. continuous dieting in a cohort of overweight and obese women
To investigate the effect on weight loss of an intermittent energy restriction compared to a continuous energy restriction, in healthy overweight to obese participants.
An intermittent energy restriction will result in greater weight loss.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 33757 0
A/Prof Jennifer Keogh
Address 33757 0
University of South Australia, GPO Box 2471, Adelaide SA 5001
Country 33757 0
Phone 33757 0
+61 8 8302 2579
Fax 33757 0
Email 33757 0
Contact person for public queries
Name 17004 0
A/Prof Ass Professor Dr. Jennifer Keogh
Address 17004 0
University of South Australia, GPO Box 2471, Adelaide SA 5001
Country 17004 0
Phone 17004 0
+61 8 8302 2579
Fax 17004 0
Email 17004 0
Contact person for scientific queries
Name 7932 0
A/Prof Ass Professor Dr. Jennifer Keogh
Address 7932 0
University of South Australia, GPO Box 2471, Adelaide SA 5001
Country 7932 0
Phone 7932 0
+61 8 8302 2579
Fax 7932 0
Email 7932 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
No IPD data for this trial will be available 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?
Journal publication details
Publication date and citation/details [1] 5924 0
Keogh, J. B., Pedersen, E. , Petersen, K. S. and Clifton, P. M. (2014), Intermittent compared to continuous diet. Clinical Obesity, 4: 150-156. doi:10.1111/cob.12052
Other publications
Have study results been made publicly available in another format?
Results – plain English summary
In a randomized parallel study, overweight and obese (body mass index [BMI] greater than or equal to 27kg/m2) women were stratified by age and BMI before randomization. Participants undertook an 8-week intensive period with weight, waist and hip circumference measured every 2 weeks, followed by 44 weeks of independent dieting. A food frequency questionnaire was completed at baseline and 12 months, from which diet quality was determined. Weight loss was not significantly different between the two groups at 8 weeks (-3.2kg CER, -2.0kg IER) or at 12 months (-4.2kg CER -2.1kg IER). Waist and hip circumference decreased significantly with time, with no difference between groups. There was an increase in the Healthy Eating Index at 12 months in the CER compared with the IER group (CER 8.4 vs. IER -0.3). This study indicates that intermittent dieting was as effective as continuous dieting over 8 weeks and for weight loss.