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Trial registered on ANZCTR


Registration number
ACTRN12617000868381
Ethics application status
Approved
Date submitted
29/05/2017
Date registered
14/06/2017
Date last updated
14/06/2017
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effects of reducing of maintaining protein intake during energy restriction on body composition, metabolism and appetite in lean to obese healthy adults.
Scientific title
The effects of reducing of maintaining protein intake during energy restriction on body composition, metabolism and appetite in lean to obese healthy adults.
Secondary ID [1] 292058 0
Nil
Universal Trial Number (UTN)
U1111-1196-8777
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obesity 303465 0
Condition category
Condition code
Diet and Nutrition 302872 302872 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study will involve 3 phases, 1) energy balance with no food diary (3 x diet recalls) (1 week), 2) Energy balance with weighed food diary (1 week) 3) Energy restriction with weighed food diary (2 weeks). During energy restriction, participants will be randomly assigned to either the main intervention group (Protein maintenance) or the control group (Protein reduction). During energy balance, participants will be instructed to continue to consume their normal diet, which based on being weight stable for greater than or equal to 6 months, should be equal to their current energy requirements. During energy restriction, participants will be required to reduce their energy intake by 33% . This will be undertaken by either reducing all macronutrients equally from their baseline intake (protein reduction), or by maintaining their habitual protein intake and reducing fat and carbohydrates equally (protein maintenance). Female participants will have a 2 week break between week 2 and 3 to monitor for timing of the menstrual cycle.

Participants will continue to consume their own diet throughout the study. Energy and macronutrient intake will be recorded using 3 diet recalls during week 1 then using a weighed food diary and recording app (myfitnesspal) during week 2-4. These will be logged into a dietetics database (Foodworks Xyris software) for accuracy. During energy restriction, participants will be given advice from the leading researcher (5+ years’ experience in dietary interventions), on how to change their energy and macronutrient goals in the app and appropriate changes to their individual diets to meet these goals. This advice will indicate for participants to reduce all portion sizes by 1/3rd or to specifically target and eliminate food with high carbohydrate and fat content from their diets. Participants will be able to track their own progress in meeting these macronutrient and energy goals on a daily basis through the app. Participants will attend the laboratory for testing on 9 occasions (10 for females due to a 2-week break), equating to, 2 times per week for the duration of the study. During these sessions participants will continue to receive face-to-face feedback and advice on meeting their dietary goals.

During test session 1 (~1.5hrs), measurements of body composition and resting energy expenditure will be undertaken. During all midweek test sessions and at the end of week 3 (sessions 2,4,6,7,8) (~20 -30minutes) body weight and body composition will be measured. At the end of week 1,2 and 4 (session 3,5,and 9) (~2.5 hours) participants will undertake measures of the body composition, resting energy expenditure, appetite and food hedoncis (liking and wanting). Appetite and liking and wanting will be assessed fasting and for 1 hour following an individualised breakfast meal comprising, muesli, milk, yogurt, fruit salad, juice and whey protein powder as required. The breakfast meal will provide 25% of each individual's habitual energy balance energy and protein intake as determined during week one from the average of 3 diet recalls. During energy restriction, the breakfast meal will be reduced by 33% according to the level of dietary energy restriction and protein intake will be either maintained or all macronutrients evenly reduced depending on the participant's allocation to the protein maintenance or protein reduction group. The energy and protein content of the participants’ meals will be individualised and adapted to the dietary interventions by changing between high and low fat dairy products, adjusting the quantities of individual food items and the inclusion of protein supplements with meals. All meals will be weighed pre and post meal consumption to determine exact energy and macronutrient intakes. Palatability will be assessed after the breakfast meal to determine any changes in the palatability of the test meal and impact on appetite and food hedonics.

The study was supervised by 2 professors with greater than 20 years experience in dietary interventions and was reviewed by an accredited practising dietician.
Intervention code [1] 298205 0
Treatment: Other
Comparator / control treatment
Protein reduction is the control treatment. (Total reduction in energy with equal reduction in all macronutrients).
Control group
Active

Outcomes
Primary outcome [1] 302278 0
Body weight will be measured using digital weighing scales. Digital weighing scales are to be used to monitor body weight of participants at home in times between laboratory visits. These scales will be calibrated regularly, and weight will also be measured at the standard laboratory sessions.
Timepoint [1] 302278 0
Measured daily at home (digital bathroom scales provided to participants)
Weight at laboratory.
- initial testing session
- 2 x per week during week 1,2,3 and 4 (mid week and end of week).
Primary outcome [2] 302279 0
Resting Energy Expenditure via indirect calorimetry
Timepoint [2] 302279 0
-Initial testing session
-At the end of week 1, 2 and 4
Primary outcome [3] 302282 0
Body composition using air displacement plethysmography (Bod Pod)
Timepoint [3] 302282 0
- initial testing session
- 2 x per week during week 1,2,3 and 4 (mid week and end of week).
Secondary outcome [1] 335352 0
Appetite measures using visual analogue scales to measure subjective appetite
Timepoint [1] 335352 0
Fasting and for 1 hour following a breakfast test meal for all 2.5-hour test sessions: End of week 1, 2 and 4
Secondary outcome [2] 335439 0
Food hedonics (liking and wanting) using the Leeds food preferences questionnaire (LFPQ)
Timepoint [2] 335439 0
Fasting and for 1 hour following a breakfast test meal for all 2.5-hour test sessions: End of week 1, 2 and 4

Eligibility
Key inclusion criteria
BMI between 20 - 40 kg/m2
Euthyroid, non-diabetic and weight stable for at least 6 months (+/-2kg)
Owning a mobile device capable of downloading Apps
Minimum age
18 Years
Maximum age
50 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Smokers (current or recent: quit less than 6 months ago)
Currently dieting
Any metabolic, liver, kidney or gastrointestinal disease
Food allergies or intolerances
Females: Irregular menstrual cycle or pregnant
Any medications known to affect metabolic rate or neuroendocrine function

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)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be stratified according to BMI (20-25, 25-30, 30-40) and gender then
randomly allocated into either the protein maintenance or protein reduction group.

Permuted block randomisation. Where protein reduction = 1 and protein maintenance = 2.
Where BMI (20-25) = A, BMI (25-30) = B, BMI (30-40) = C, Gender (Male) = D, Gender (Female) = E. Each participant will therefore fall into one of six cell options: AD, AE, BD, BE, CD, CE. Each cell will have alternate sequence 1 or 2.
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
Linear Mixed models will be used to determine differences between groups and between the test sessions for the key outcome measures.

Previous studies have found changes in the magnitude of -299 to -662 KJ in response to similar ER protocols (~23-30% energy deficit) after interventions of 4 days to 2 weeks [1,2]. A change in REE of greater than day-to-day variability reported in previous studies of up to 6% (~400 KJ) [3] is recommended to establish a true change in REE above day-to-day variability. At a power of 0.8 and alpha of 0.05, recruitment of 11 participants per group would allow for finding an effect size of 0.92 (large effect), which based on the SD of REE change in response to a similar 4-day 27% energy deficit (SD 425 KJ) [1] would allow for finding changes in REE of 398 KJ.

1. Kouda, K., et al., Metabolic response to short-term 4-day energy restriction in a controlled study. Environmental health and preventive medicine, 2006. 11(2): p. 89-92.
2. Doucet, E., et al., Evidence for the existence of adaptive thermogenesis during weight loss. The British Journal of Nutrition, 2001. 85(6): p. 715.
3. Roffey, D.M., N. Byrne, and A. Hills, Day-to-day variance in measurement of resting metabolic rate using ventilated-hood and mouthpiece & nose-clip indirect calorimetry systems Journal of Parenteral and Enteral Nutrition 2006. 30(5): p. 426-432.

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)
QLD

Funding & Sponsors
Funding source category [1] 296591 0
University
Name [1] 296591 0
Queensland University of Technology
Address [1] 296591 0
Institute of Health and Biomedical Innovation
60 Musk Avenue Kelvin Grove,
QLD, 4059
Country [1] 296591 0
Australia
Primary sponsor type
University
Name
Queensland University of Technology
Address
Institute of Health and Biomedical Innovation
60 Musk Avenue Kelvin Grove,
QLD, 4059
Country
Australia
Secondary sponsor category [1] 295543 0
None
Name [1] 295543 0
Address [1] 295543 0
Country [1] 295543 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 297812 0
Queensland University of Technology Human Research Ethics Committee
Ethics committee address [1] 297812 0
Victoria Park Rd
Kelvin Grove, Qld, 4059
Ethics committee country [1] 297812 0
Australia
Date submitted for ethics approval [1] 297812 0
01/12/2015
Approval date [1] 297812 0
15/02/2016
Ethics approval number [1] 297812 0
1500001111

Summary
Brief summary
Energy restriction to induce weight loss presents a physiologically challenging process as the effects of energy restriction often include a downregulation of metabolic processes and increases in the motivation to eat. Manipulation of the macronutrient content of the diet particularly in regards to protein, has been proposed as a potential beneficial strategy to maintain metabolic processes and appetite. Changes in protein intake irrespective of changes in energy intake may effect metabolism and appetite and therefore this study aimed to determine whether maintaining habitual protein intake, rather than reducing protein intake during energy restriction would be adequate to minimise the commonly seen energy restriction induced adaptive changes in REE and appetite.

The key aims of this study where to compare the short term effects of protein maintenance versus protein reduction during energy restriction, on changes in body weight, body composition, resting energy expenditure, appetite and food liking and wanting.
During energy balance participants consumed their own habitual weight maintenance diet, and during energy restriction, participants were given guidelines on how to make changes to their own diet to meet specific energy and macronutrient goals based on providing 67% of each individual’s habitual diet and tailed to either protein maintenance or protein reduction.
Trial website
Trial related presentations / publications
Nil to date
Public notes

Contacts
Principal investigator
Name 75174 0
Mrs Leonie Ruddick-Collins
Address 75174 0
Queensland University of Technology, Institute of Health and Biomedical Innovation
60 Musk Avenue,
Kelvin Grove, QLD
4059
Country 75174 0
Australia
Phone 75174 0
+61 7 3138 6397
Fax 75174 0
Email 75174 0
l.huckle@hdr.qut.edu.au
Contact person for public queries
Name 75175 0
Mrs Leonie Ruddick-Collins
Address 75175 0
Queensland University of Technology, Institute of Health and Biomedical Innovation
60 Musk Avenue,
Kelvin Grove, QLD
4059
Country 75175 0
Australia
Phone 75175 0
+61 7 3138 6397
Fax 75175 0
Email 75175 0
l.huckle@hdr.qut.edu.au
Contact person for scientific queries
Name 75176 0
Mrs Leonie Ruddick-Collins
Address 75176 0
Queensland University of Technology, Institute of Health and Biomedical Innovation
60 Musk Avenue,
Kelvin Grove, QLD
4059
Country 75176 0
Australia
Phone 75176 0
+61 7 3138 6397
Fax 75176 0
Email 75176 0
l.huckle@hdr.qut.edu.au

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