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Trial registered on ANZCTR

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

Titles & IDs
Public title
The effect of diet and portion size on oral fatty acid sensitivity
Scientific title
In overweight and obese subjects, will following a low-fat diet, or following a portion control diet, have an effect on oral fatty acid sensitivity.
Secondary ID [1] 262484 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 268157 0
Diet 268158 0
Anxiety 268159 0
Condition category
Condition code
Diet and Nutrition 268291 268291 0 0
Mental Health 268368 268368 0 0

Study type
Description of intervention(s) / exposure
This group will follow a low-fat diet (25% total dietary fat from energy) for 6 weeks. The low-fat diet consists of subjects consuming 5 serves of vegetables per day, 2 serves of fruit per day, 3 serves of low-fat dairy per day, a maximum of 5 serves of carbohydrates (rice, pasta, bread etc) per day and a maximum of 3 serves of fats (butter oil, margarine etc) per day. Subjects are also given a list of foods to try and avoid, including fatty snacks like chips, biscuits cakes etc. Subjects will undergo a one on one dietary counseling session with the nutritionist where the diet they will be following will be explained to them, and questions they may have will be answered. This counseling session occurs once at the beginning of the study, but a weekly phone call will be made to subjects to give them the opportunity to ask questions throughout the 6 week period.
Intervention code [1] 266827 0
Intervention code [2] 266904 0
Treatment: Other
Intervention code [3] 266905 0
Comparator / control treatment
This group will follow a portion control diet for 6 weeks. Subjects will be given a plate to use to reduce their portion sizes of their main meals. Subjects in this group will be advised by the nutritionist in their one on one counseling session to reduce everything they are now consuming. They will be told that they do not have to change what they are eating, just the amount. They will also be told that they are not to make up for eating smaller meals by snacking more regularly.
Control group

Primary outcome [1] 269024 0
Oral sensitivity to oleic acid will be measured using 3-alternate forced choice methodology, where they need to accurately differentiate between control samples and those containing a certain concentration of oleic acid in ascending order from lowest concentration (0.02mM) to the highest (12mM). Samples are presented to subjects in non-fat milk. Subjects are presented with 3 samples, 2 control and one fatty acid and asked to pick the odd sample. Subjects are advised to wash their mouth only between tests, not between individual samples within the same test. Detection thresholds for each fatty acid were defined as the concentration at which the subject correctly picked the odd sample out in three consecutive sample sets.
Timepoint [1] 269024 0
Oral sensitivity will be measured at baseline and week 6.
Primary outcome [2] 269025 0
Fatty acid taste receptors will be measured by collecting tongue tissue via non-invasive tongue swabs and running these cells in real time Polymerase Chain Reaction (PCR).
Timepoint [2] 269025 0
Tongue cells will be collected at baseline and week 6.
Primary outcome [3] 269026 0
Anxiety will measured using the Spielberger State-Trait Anxiety Inventory.
Timepoint [3] 269026 0
This will be measured at baseline and week 6.
Secondary outcome [1] 276859 0
Food and fat intake: Subjects completed a 24 hour diet diary from which energy and macronutrient contents were quantified, they also completed a a food frequency questionnaire, to assess dietary variety.
Timepoint [1] 276859 0
The diet diary will be recorded at baseline, week 2, week 3, week 4 and week 6. And the food frequency questionnaire will be recorded at baseline and week 6.
Secondary outcome [2] 276861 0
Subjects will have a photograph of their tongue taken to determine if the number of taste buds they have on their tongue is related to their sensitivity to fatty acids.
Timepoint [2] 276861 0
This will be measured at week 6 only.
Secondary outcome [3] 276942 0
Height, weight and body mass index
Timepoint [3] 276942 0
At baseline and week 6, all subjects will be weighted and measured without shoes and in light clothing. Body mass Index (BMI) was calculated from these measurements.

Key inclusion criteria
Non-smokers, Body Mass Index (BMI) > 20
Minimum age
18 Years
Maximum age
75 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Smokers, BMI < 20

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The person who determined if a subject was eligible for inclusion into the trial was unaware when the decision was made as to which intervention the subject would be allocated to. Allocation was concealed by contacting the holder of the allocation schedule who was 'off site'.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a coin-toss.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
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] 267309 0
Name [1] 267309 0
Deakin University
Address [1] 267309 0
School of Exercise and Nutrition Sciences
221 Burwood Highway
Burwood, VIC 3125
Country [1] 267309 0
Primary sponsor type
Associate Professor Russell Keast
School of Exercise and Nutrition Sciences
221 Burwood Highway
Burwood, VIC 3125
Secondary sponsor category [1] 266422 0
Name [1] 266422 0
Address [1] 266422 0
Country [1] 266422 0

Ethics approval
Ethics application status
Ethics committee name [1] 269300 0
Deakin University Human Research Ethics Committee
Ethics committee address [1] 269300 0
Deakin University
221 Burwood Highway
Burwood, VIC 3125
Ethics committee country [1] 269300 0
Date submitted for ethics approval [1] 269300 0
Approval date [1] 269300 0
Ethics approval number [1] 269300 0

Brief summary
The primary purpose of this study is to investigate the effect of diet on people's ability to detect fatty acids in the oral cavity.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 32788 0
Address 32788 0
Country 32788 0
Phone 32788 0
Fax 32788 0
Email 32788 0
Contact person for public queries
Name 16035 0
Associate Professor Russell Keast
Address 16035 0
School of Exercise and Nutrition Sciences
221 Burwood Highway
Burwood, VIC 3125
Country 16035 0
Phone 16035 0
Fax 16035 0
Email 16035 0
Contact person for scientific queries
Name 6963 0
Associate Professor Russell Keast
Address 6963 0
School of Exercise and Nutrition Sciences
221 Burwood Highway
Burwood, VIC 3125
Country 6963 0
Phone 6963 0
Fax 6963 0
Email 6963 0

No information has been provided regarding IPD availability
Summary results
No Results