Using the Norm Range to Predict the Effect of Food Portion Size Reductions on Compensation Over 5 Days

Study Overview
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Brief Summary
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Reducing food portion size is a potential strategy to reduce energy intake. However it is unclear at what point consumers compensate for reductions in portion size by increasing energy intake from other items. This could result in no overall benefit of reducing food portion sizes. The investigators tested the hypothesis that reductions to the portion size of components of a main meal will only result in significant compensatory eating when the reduced portion size is no longer visually perceived as 'normal'. In a crossover experiment, participants were served different sized portions during lunch and dinner over 5 days: a 'large-normal', a 'small-normal', and a 'smaller than normal' portion. Intake from all other meal components consumed in the laboratory were measured.

Official Title
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Using the Norm Range to Predict the Effect of Food Portion Size Reductions on Compensation

Conditions
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Portion Size

Intervention / Treatment
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* Behavioral: portion size


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: willing to consume the test foods BMI between 22.5 - 32.5 Exclusion Criteria: food allergies, intolerances or specific dietary requirements (including being vegetarian or vegan) history of eating disorders taking medication which affected appetite participated in a portion size studies in the past 12 months, or in dieting or weight loss trials in the past 4 weeks

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Intervention/Treatment |
| --- |
|Behavioral: portion size|Smaller than normal portion size - the intervention is the main meal component size perceived as 'smaller than normal' that participants are provided with during lunch and dinner in the laboratory. Small-normal portion size - the intervention is the main meal component size perceived as 'small-normal' that participants are provided with during lunch and dinner in the laboratory. Large-normal portion size - the intervention is the main meal component size perceived as 'large-normal' that participants are provided with during lunch and dinner in the laboratory.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute compensatory energy intake | Energy intake from main meal components that are not varied by portion size | Immediate (within single meal occasion) | 
| Total meal energy intake | Energy intake from all main meal components (including those that are and are not varied by portion size) | Immediate (within single meal occasion) | 
| Total daily energy intake | Energy intake from all foods consumed, including those provided in the laboratory and those self-reported | Over 5 x full days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Moderate-vigorous physical activity | Moderate-vigorous physical activity (recorded using accelerometer device) | Over 5 x full days | 
| Discretionary Leisure-time physical activity | Discretionary Leisure-time physical activity (recorded with self-report measure International Physical Activity Questionnaire) | Over 5 x full days | 
| Appetite | Hunger and fullness sensations before and after laboratory-based meals (self-reported on visual analog scales anchored at 0 'not at all' to 100 'extremely') | Over 5 x full days (measured before and after each meal occasion) |