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Trial registered on ANZCTR


Registration number
ACTRN12614000944639
Ethics application status
Approved
Date submitted
12/08/2014
Date registered
3/09/2014
Date last updated
24/07/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effectiveness of a weight loss intervention to improve decision-making skills in adults with overweight and obesity.
Scientific title
Effectiveness of a weight loss intervention based on diet and physical exercise to improve cognitive decision-making skills in adults with overweight and obesity compared with non-treated individuals.
Secondary ID [1] 285093 0
Nil Known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Overweight and obesity 292625 0
Condition category
Condition code
Diet and Nutrition 292943 292943 0 0
Obesity
Mental Health 293213 293213 0 0
Studies of normal psychology, cognitive function and behaviour

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The intervention of this study is a 12-week weight management program that aims to reduce weight (and therefore, visceral adipose tissue) in 40 overweight or obese participants. The weight management program consists of a modified intermittent fasting regimen supported by a dietitian and the promotion of physical activity.

Participants self-selected to the intervention group will undergo an initial nutritional assessment face-to-face with a dietitian at the university’s dietetics clinic. Participants will receive individualised nutrition care in the form of intensive nutrition assessment and nutrition intervention via face-to-face interviews. The dietary program has been designed to be evidence based and is optimised for loss of body fat and to preserve lean mass.

These interviews will be scheduled at 6 different time points (Week 0, Week 1, Week 2, Week 4-6, Week 8-10, Week 12-14). The detailed initial dietetic interview will be approximately 45 to 60 minutes in duration and follow-up dietetic interviews will approximately 15 to 30 minutes in duration. A detailed diet history will be carried out at Week 0 with all subsequent review follow-ups to monitor intervention adherence via 2 x 24 hour-recalls. Food diaries may be utilised if desired by the participant. The dietitian interviewer will attempt to ascertain information in the areas of; i) weight and waist circumference, ii) oral intake/food intake, iii) clinical issues, iv) physical activity and v) any other relevant dietary information. Participants will be encouraged to partake in light and regular physical activity.

Participants will be encouraged to schedule at least three 30 minute sessions of light physical activity each week. They will be strongly advised by the dietitian to seek professional medical advice by the dietitian if they intend to pursue more intense physical activity. Pedometers will be provided to each participant to track their daily physical activity levels

Intervention code [1] 289952 0
Treatment: Other
Intervention code [2] 290156 0
Lifestyle
Comparator / control treatment
Comparators: non-weight reduced group and a healthy weight control group (no treatment is administered to these groups).
Control group
Active

Outcomes
Primary outcome [1] 292806 0
Improvement in decision-making measured as behavioural performance on neuropsychological tests.

- Iowa Gambling Task – measure of decision-making under conditions of uncertainty and risk of punishment. Participants make 100 card choices from 4 decks. Decks A and B offer high rewards ($100 per win), but higher losses. Decks C and D offer only $50 per win, but smaller losses resulting in profit over time. The main dependent measure is the number of safe choices (C+D) minus the number of risky choices (A+B) over the 100 trials.
- Worth the Effort Task – measure of effort-based decision-making. In this task, participants are instructed to choose between two different task difficulty levels in order to gain monetary rewards. In each trial, the subject is presented with a choice between a ‘hard task’ and an ‘easy task’, which require different amounts of speeded manual button pressing. If they successfully completed the easy task, subjects are eligible to win the same amount of money on each trial ($1). In successfully completed hard-task choices, subjects are eligible to win higher amounts of money ($1.24-$4.30) on each trial. The main dependent measure of this task is the ratio between easy and hard task choices.

Timepoint [1] 292806 0
After 3 months.
Secondary outcome [1] 309784 0
Change in body composition (fat and lean mass) as assessed using the GE Lunar Dual-Energy X-ray Absorptiometry (iDXA) Scanner.
Timepoint [1] 309784 0
After 3 months.
Secondary outcome [2] 309786 0
Changes in impulsivity and compulsivity measured as behavioural performance on neuropsychological tests.

- Reversal Learning – measure of learning by reward or punishment. Participants learn a particular stimulus- response pattern. After they learn this, the stimulus-response pattern changes and they need to relearn the new pattern. The dependent measure of this task is how fast people relearn the new pattern based on whether they are rewarded or punished for their performance.
- Stop Signal Task - measure of reaction time and motor inhibitory control. Participants have to respond as quickly as possible, but on some trials they must withhold their response if they hear the stop signal. The dependent measure of this task is the mean stop-signal reaction time, which measures the speed of the inhibitory process, and is calculated by subtracting the stop-signal delay from the mean response time to go trials.



Timepoint [2] 309786 0
After 3 months.

Eligibility
Key inclusion criteria
Healthy weight adults: Age between 18 and 60; Body Mass Index (BMI) between 18 kg/m2 – 24.9kg/m2

Excess weight adults: Age between 18 and 60; Body Mass Index (BMI) between 25 kg/m2 – 40kg/m2
Minimum age
18 Years
Maximum age
60 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Overweight participants who are taking part in the weight management program: (1) current or previous pregnancy (within past 6 months) or lactating; (2) history of substance
use (drug or alcohol); (3) history of head trauma or neurological illness impacting Central Nervous System or undergone radiation treatment; (4) current diagnosis of depression; (5) unable to read and converse in English; (6) clinically diagnosed or screen positive for disordered eating.

Normal-weight and overweight participants no taking part in the weight management program: (1) current or previous pregnancy (within past 6 months) or lactating; (2) current or recent history of health condition (including cancer; thyroid disease; surgery; hepatic disease; stage 3-5
CKD; eating disorders; those who have previously undergone radiation treatment); (3) current comorbid medical conditions associated with excess weight (e.g., type II diabetes, hypertension); (4) has undergone weight loss surgery; (5) taking weight loss drugs; (6) history of substance use (drug or alcohol); (7) history of head trauma or neurological illness impacting Central Nervous System; (8) current diagnosis of depression; (9) has lactose intolerance; (10) unable to read and converse and English; (11) clinically diagnosed or screen positive for disordered eating using.

Eligible overweight and obese participants are healthy volunteers. Participants will be asked to provide a finger prick blood sample in order to measure fasting plasma glucose. If a blood glucose reading greater than or equal to 7.0mmol/l is recorded which is indicative of diabetes, the participant will be referred to their GP and not able to proceed further with the study. Furthermore, blood pressure will be measured with an automated sphygmomanometer. If a blood pressure reading greater than or equal to 140/90 mm Hg is recorded which is indicative of hypertension, the participant will not be able to proceed further with the study.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be divided in 2 groups according to their body weight mass (BMI): normal-weight (BMI between 18 and 24) and overweight (BMI between 25 and 40). Overweight participants will then be asked if they wish to take part in the weight management program. If they do not wish to take part
in the weight management program, they will be allocated to the overweight control group.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Sample size has been estimated with GPOWER software based on our previous longitudinal study which measured decision-making skills before and after a 12-week weight loss intervention (Delgado-Rico et al., 2012). Assuming a medium effect size improvement in decision-making, 80% power and 0.05 alpha levels, we will need 111 participants. We will recruit 120 participants to have the same number of individuals in each of the 3 groups.


Mixed-design repeated measures will be used to assess the impact of the weight loss program on body composition (lean and fat mass).

Mixed-design repeated measures models will assess the impact of body fat loss on impulsivity and compulsivity performance changes. Regression models including body fat loss as the predictor and impulsivity and compulsivity performance scores as the dependent variables will be used to test whether adiposity impacts impulsivity and compulsivity.

Delgado-Rico, E., Rio-Valle, J.S., Albein-Urios, N., Caracuel, A., Gonzalez-Jimenez, E., Piqueras, M.J., Brandi, P., Ruiz-Lopez, I.M., Garcia-Rodriguez, I., Martin-Matillas, M., Delgado-Fernandez, M., Campoy, C., Verdejo-Garcia, A.J., 2012, Effects of a multicomponent behavioral intervention on impulsivity and cognitive deficits in adolescents with excess weight, Behavioural Pharmacology [P], vol 23, issue 5-6, Lippincott Williams & Wilkins, United States, pp. 609-615.

Recruitment
Recruitment status
Stopped early
Data analysis
Data collected is being analysed
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
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)
VIC

Funding & Sponsors
Funding source category [1] 289712 0
University
Name [1] 289712 0
Monash University
Address [1] 289712 0
Monash University - Wellington Road - Clayton - Victoria 3800
Country [1] 289712 0
Australia
Primary sponsor type
University
Name
School of Psychological Sciences - Monash University
Address
Monash University, Faculty of Medicine, Nursing and Health Sciences - Building 17, Wellington Road - Clayton - Victoria 3800
Country
Australia
Secondary sponsor category [1] 288414 0
University
Name [1] 288414 0
Be Active Sleep Eat (BASE) Facility - Department of Nutrition and Dietetics - Monash University
Address [1] 288414 0
Monash University, Faculty of Medicine, Nursing and Health Sciences - Level 1, 264 Ferntree Gully Road - Notting Hill- VIC 3168, Australia
Country [1] 288414 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 291451 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 291451 0
Monash University
Level 1, Building 3e, Clayton Campus
Wellington Rd
Clayton VIC 3800, Australia
Ethics committee country [1] 291451 0
Australia
Date submitted for ethics approval [1] 291451 0
23/05/2014
Approval date [1] 291451 0
21/07/2014
Ethics approval number [1] 291451 0
CF14/1599 - 2014000769

Summary
Brief summary
The prevalence of obesity has steeply grown in the last decades due to changes in food production, marketing and availability. Food intake largely rests on our ability as an individual to manage to control eating and drinking behaviours within the context of an obesogenic environment.

Importantly, it has been found that overweight adults with higher levels of visceral fat have a poorer performance on measurers of risk taking and impulsive behaviours than healthy weight adults with low visceral fat. Those with higher levels of visceral fat are more likely to engage in greater risk taking behaviours and have more unhealthy food choices to those who have less visceral fat stores. It has been shown that visceral fat is more strongly related to cognition than body mass index (BMI).

We aim to investigate: (a) the association between visceral fat and cognition, specifically performance as measured by behavioural tests of impulsivity, compulsivity and decision-making; (b) whether reductions in visceral fat are associated with improvement in cognitive control.
Trial website
Trial related presentations / publications
Mata F, Treadway M, Kwok A, Truby H, Yücel M, Stout JC, Verdejo-Garcia A.
Reduced Willingness to Expend Effort for Reward in Obesity: Link to Adherence to
a 3-Month Weight Loss Intervention. Obesity (Silver Spring). 2017
Oct;25(10):1676-1681. doi: 10.1002/oby.21948.
Public notes

Contacts
Principal investigator
Name 50354 0
A/Prof Antonio Verdejo-Garcia
Address 50354 0
School of Psychological Sciences (Building 17) - Faculty of Medicine, Nursing and Health Sciences. Monash University - Wellington Road - Clayton - Victoria 3800
Country 50354 0
Australia
Phone 50354 0
61 3 99055374
Fax 50354 0
Email 50354 0
antonio.verdejo@monash.edu
Contact person for public queries
Name 50355 0
A/Prof Antonio Verdejo-Garcia
Address 50355 0
School of Psychological Sciences (Building 17) - Faculty of Medicine, Nursing and Health Sciences. Monash University - Wellington Road - Clayton - Victoria 3800
Country 50355 0
Australia
Phone 50355 0
+61399055374
Fax 50355 0
Email 50355 0
antonio.verdejo@monash.edu
Contact person for scientific queries
Name 50356 0
A/Prof Antonio Verdejo-Garcia
Address 50356 0
School of Psychological Sciences (Building 17) - Faculty of Medicine, Nursing and Health Sciences. Monash University - Wellington Road - Clayton - Victoria 3800
Country 50356 0
Australia
Phone 50356 0
+61399055374
Fax 50356 0
Email 50356 0
antonio.verdejo@monash.edu

No data has been provided for results reporting
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