Randomised within subjects cross-over study (n=94) exploring the cognitive and physiological processes associated with portion control. Participants will eat a self-served lunch using a portion control plate vs. a conventional (control) plate on two separate occasions under a controlled laboratory environment. Portion size, meal micro-structure, attention, memory and satiety markers will be analysed. The portion control plate is a prototype designed in collaboration with the commercial partner for this study and is based on published evidence. It includes sectors and pictures indicating amounts to serve from starchy food, protein and vegetables. The control plate will be of the same background colour, size and shape but without any pictures or demarcations. The main study outcome is attention time on areas of interest in the plate corresponding to main foods groups, across plate conditions.
The size and design of tableware have been proposed as a potentially effective strategy to modulate how much is eaten at a meal. The mechanisms by which specific tableware may work however are not known, in particular the cognitive processes associated with visual stimuli. In this covert trial, 68 women (34 overweight or obese) and 26 lean men (exploratory sub-study) will self-serve and consume food from a laboratory buffet using a portion control plate with visual stimuli for appropriate amounts of main food groups, or a conventional plate, on two different days in random order. On both sessions participants will complete behavioural and cognitive tests to measure visual attention during the meal (eyetracking device), meal microstructure (Universal Eating Monitor), episodic memory for portion sizes (computerised test), portion size choice, food intake, subjective appetite and satiety, cephalic and intestinal satiety responses. Further behavioural tests include meal liking, expected satiety, portion size perceptions and tool acceptance ratings. The main study outcome is difference in proportional dwell time on areas of interest in the plate corresponding to main foods groups (women), or difference in bite size (men) across conditions. Secondary outcomes for all subjects include: portion size for overall meal and meal components, eating rate, bite size, deceleration rate, portion size memory error, portion size norms, portion control self-efficacy, tool acceptance, energy compensation for the rest of the day, plus blood insulin, glucose, pancreatic polypeptide and ghrelin up to 90 min post-meal (sub-sample of 34 women, 50% being overweight/obese). Analyses by gender and BMI sub-groups will be applied when possible. The results of this study will help to better understand the potential mechanisms by which portion control tools with visual cues may work, and to improve the design of current instruments for their application in nutritional interventions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
76
Portion control plate including demarcations and pictures for recommended amounts of main food groups (starch, protein and vegetables), 25 cm in diameter, enamel, white background.
Conventional plate without demarcations or images, 25 cm in diameter, enamel, white.
Centre for Nutrition Research, University of Navarra
Pamplona, Navarre, Spain
Dwell time difference (women)
Difference in proportional dwell time on three areas of interest in the plate corresponding to main food groups i.e. starch, protein and vegetables, measured in milliseconds, as a proxy for attention levels, between the Portion Control Plate condition and the conventional plate condition.
Time frame: Month 24
Bite size difference (men)
Difference in the amount of food loaded on the fork estimated from the difference in grams between two consecutive weight records as measured by the Universal Eating Monitor, between the Portion Control Plate condition and the conventional plate condition.
Time frame: Month 24
Eating rate difference
Difference in grams of food consumed per minute as measured by the Universal Eating Monitor, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Bite size difference (women)
Difference in the amount of food loaded on the fork estimated from the difference in grams between two consecutive weight records as measured by the Universal Eating Monitor, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Deceleration rate difference
Difference in the change in eating rate over the course of the meal measured in grams per squared second, as recorded by the Universal Eating Monitor, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Meal duration difference
Difference in the duration of the meal in minutes, starting when the investigator places the food on the table and finishing when the volunteer pressed the bell, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Dwell time difference (men)
Difference in proportional dwell time on three areas of interest in the plate corresponding to main food groups i.e. starch, protein and vegetables, measured in milliseconds, as a proxy for attention levels, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Difference in portion size at meal
Difference in portion sizes in grams for the complete meal and for each meal component (i.e. rice, vegetables, meatballs, bread, fruit, condiments and water), between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Percent memory reconstruction error (Portion Control Plate)
Percent error between recalled and real portion size calculated by subtracting the recalled portion size for each meal component at 3 hours post-meal, from the actual portion sizes chosen during the test meal and dividing by the actual portion size, using data from a computer-based memory reconstruction task (XnConvert software), for the Portion Control Plate condition. Interpreted as 0% = perfect match between recalled and actual portion size.
Time frame: Month 21
Percent memory reconstruction error (conventional plate)
Percent error between recalled and real portion size calculated by subtracting the recalled portion size for each meal component at 3 hours post-meal, from the actual portion sizes chosen during the test meal and dividing by the actual portion size, using data from a computer-based memory reconstruction task (XnConvert software), for the conventional plate condition. Interpreted as 0% = perfect match between recalled and actual portion size.
Time frame: Month 21
Percent memory reconstruction error difference
Difference in the percent memory reconstruction error for each meal component at 3 hours post-meal, between the Portion Control Plate and the conventional plate condition.
Time frame: Month 24
Percent energy compensation (EC)
Energy adjustment after the meal and for the remaining of the day, calculated from food intake data collected via an 8h food diary and using a published algorithm (Almiron-Roig et al. 2013). Interpreted as EC of 100% = perfect compensation; \<100% = undercompensation; \>100% overcompensation.
Time frame: Month 21
Percent energy compensation difference
Difference in percent energy compensation after the meal and for the remaining of the day, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Portion size norms
Visual analogue scale ratings (0 -100 mm) for habitual portion size for the meal, rice, vegetables and meatballs consumed during the test meal. Interpreted as: a score of 50 mm = the chosen portion equals the habitual portion size; \>50 mm = chosen portion is smaller than habitual; \<50 mm = chosen portion is larger than habitual.
Time frame: Month 21
Portion size norms difference
Difference in Visual Analogue Scale ratings for portion size norms for the whole meal, rice, vegetables and meatballs between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Liking for the meal differences
Difference in visual analogue scale ratings (0-100 mm) for Liking of the meal after consumption between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Baseline subjective appetite
Visual analogue scale ratings (0-100 mm) for perceived hunger before the meal (time 0)
Time frame: Month 21
Baseline subjective satiety
Visual analogue scale ratings (0-100 mm) for perceived fullness before the meal (time 0)
Time frame: Month 21
Baseline subjective thirst
Visual analogue scale ratings (0-100 mm) for perceived thirst before the meal (time 0)
Time frame: Month 21
Baseline subjective nausea
Visual analogue scale ratings (0-100 mm) for perceived nausea before the meal (time 0)
Time frame: Month 21
Post-meal subjective appetite
Visual analogue scale ratings (0-100 mm) for perceived hunger immediately after the meal (time 1)
Time frame: Month 21
Post-meal subjective satiety
Visual analogue scale ratings (0-100 mm) for perceived fullness immediately after the meal (time 1)
Time frame: Month 21
Post-meal subjective thirst
Visual analogue scale ratings (0-100 mm) for perceived thirst immediately after the meal (time 1)
Time frame: Month 21
Post-meal subjective nausea
Visual analogue scale ratings (0-100 mm) for perceived nausea immediately after the meal (time 1)
Time frame: Month 21
3 h subjective appetite
Visual analogue scale ratings (0-100 mm) for perceived hunger 3 hours after consuming the meal (time 2)
Time frame: Month 21
3 h subjective satiety
Visual analogue scale ratings (0-100 mm) for perceived fullness 3 hours after consuming the meal (time 2)
Time frame: Month 21
3 h subjective thirst
Visual analogue scale ratings (0-100 mm) for perceived thirst 3 hours after consuming the meal (time 2)
Time frame: Month 21
3 h subjective nausea
Visual analogue scale ratings (0-100 mm) for perceived nausea 3 hours after consuming the meal (time 2)
Time frame: Month 21
Difference in subjective appetite and satiety scores
Difference in scores of visual analogue scale ratings (0-100 mm) for perceived hunger, fullness, thirst and nausea at baseline, post-meal and 3 hours after consuming the meal, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Difference in expected satiation for the meal
Difference in visual analogue scale rating (0-100 mm) before consuming the meal, between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Baseline blood glucose
Blood glucose levels before starting the meal
Time frame: Month 21
Post-meal blood glucose
Blood glucose levels at 5, 10, 30, 60 and 90 min after starting the meal
Time frame: Month 21
Difference in post-meal blood glucose
Difference in blood glucose levels at 5, 10, 30, 60 and 90 min after starting the meal between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 21
Baseline blood insulin
Blood insulin levels before starting the meal
Time frame: Month 21
Post-meal blood insulin
Blood insulin levels at 5, 10, 30, 60 and 90 min after starting the meal
Time frame: Month 21
Difference in post-meal blood insulin
Difference in blood insulin levels at 5, 10, 30, 60 and 90 min after starting the meal between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Baseline blood pancreatic polypeptide
Blood pancreatic polypeptide levels before starting the meal
Time frame: Month 21
Post-meal blood pancreatic polypeptide
Blood pancreatic polypeptide levels at 5, 10, 30, 60 and 90 min after starting the meal
Time frame: Month 21
Difference in post-meal blood pancreatic polypeptide
Difference in blood pancreatic polypeptide levels at 5, 10, 30, 60 and 90 min after starting the meal between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Baseline blood ghrelin
Blood ghrelin levels before starting the meal
Time frame: Month 21
Post-meal blood ghrelin
Blood ghrelin levels at 5, 10, 30, 60 and 90 min after starting the meal
Time frame: Month 21
Difference in post-meal blood ghrelin
Difference in blood ghrelin levels at 5, 10, 30, 60 and 90 min after starting the meal between conditions (Portion Control Plate vs. conventional plate).
Time frame: Month 24
Body Mass Index
Weight in kilograms divided by height in squared meters measured at the start of the trial.
Time frame: Month 18
Age
Age in years measured at the start of the trial.
Time frame: Month 18
Eating behaviour profile from the Three Factor Eating Questionnaire (TFEQ)
Restraint, disinhibition and susceptibility to hunger scores from the Three Factor Eating Questionnaire for the Spanish population (Sánchez-Carracedo et al. 1999, Psicol Conduct 7:393-416) measured at the end of the trial.
Time frame: Month 21
Eating behaviour profile from the Eating Attitudes Test (EAT-26)
Susceptibility to eating disorders score using the Eating Attitudes Test (EAT-26) the Spanish population (Rivas et al. 2010; Span J Psychol 13:1044-1056) measured at the start of the trial.
Time frame: Month 18
Difference in portion control self-efficacy
Difference in portion control self-efficacy score derived from the Portion Control Self-Efficacy Scale (Fast et al.2015) between conditions (Portion Control Plate vs. conventional plate). The scale ranges from 1 to 5. A combined score will be obtained for questions 1,2, 3, 5, 7,8 and the reverse of questions 4 and 6, by adding up all the scores from each of the 8 Likert scales, and dividing the sum by 8. A score between 1-2.5 will be interpreted as 'none to low self-efficacy'; a score between 2.5-3.5 will be interpreted as 'neutral self-efficacy', a score between 3.5-5 will be interpreted as 'medium to high self-efficacy'.
Time frame: Month 24
Difference in portion tool acceptance
Difference in portion tool acceptance score derived from a published questionnaire (Almiron-Roig et al., 2016) between conditions (Portion Control Plate vs. conventional plate). A combined score will be obtained for questions a, b, c, e, f, g and the reverse of d by adding up all the scores from each of the 4 Likert scales, and dividing the sum by 7. A score between 1-2.5 will be interpreted as 'none to low acceptance'; a score between 2.5-3.5 will be interpreted as 'neutral acceptance', a score between 3.5-5 will be interpreted as 'medium to high acceptance'.
Time frame: Month 24
Self-reported ethnicity
Ethnicity group defined using a check-list, measured at the start of the trial.
Time frame: Month 18
Household composition
Number of adults and children aged 18 or less living in the same household (checklist) measured at the start of the trial.
Time frame: Month 18
Take away food consumption
Frequency of take away food consumption (checklist), measured at the start of the trial.
Time frame: Month 18
Home-made meal consumption
Frequency of home-made meal consumption (checklist), measured at the start of the trial.
Time frame: Month 18
Cooking pattern
Cooking for self only vs. cooking for self and others (checklist), measured at the start of the trial.
Time frame: Month 18
Previous experience with portion tools
Previous experience with portioning utensils, portion control tools, measuring utensils etc. (open ended question), measured at the start of the trial.
Time frame: Month 18
Food intake for remaining of the day
8h food record to complete after the laboratory test meal, for both conditions (Portion Control Plate and conventional plate).
Time frame: Month 21
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