Effects of Variety and Portion Size on Meal Intake of Adults

Study Overview
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Brief Summary
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The primary purpose of this study is to gain a better understanding of the combined effects of meal variety and portion size on food intake at a meal. The study will also explore relationships with eating microstructure such as eating rate and bite size. Additionally, other individual characteristics will be examined for their influence on the effects of variety and portion size on meal intake.

Official Title
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Effects of Variety and Portion Size on Meal Intake of Adults

Conditions
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Eating Behavior

Intervention / Treatment
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* Other: Low variety
* Other: High Variety
* Other: Small Portion Size
* Other: Large Portion Size
* Other: With Beverage
* Other: Without Beverage


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Be willing and able to travel to Penn State University Park campus weekly for meals Be fully vaccinated against COVID-19 Be a woman 20 - 65 years old Regularly eat 3 meals/day Be willing to refrain from drinking alcohol the day before and during test days Have a body mass index between 18.0 and 35.0 kg/m*m Be willing to refrain from eating after 10 pm the evening before test sessions Be willing to participate in all study procedures Exclusion Criteria: Must not be a smoker Must not be an athlete in training Must not be pregnant or breastfeeding at the time of screening Must not have taken prescription or non-prescription drugs that may affect appetite or food intake within the last 3 months Must not dislike or be unable to eat the test foods (because of allergies, intolerance, or dietary restrictions) Must not be currently dieting to gain or lose weight Must not have a health condition that affects appetite Must not have participated in a similar study in our lab in the past year Must not be a student, faculty, or staff member in nutritional sciences or psychology

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low Variety Small Portion Without Beverage<br>Test meal with food components mixed together (low variety) with a small portion of food served without water | Other: Low variety<br>* Meal components are mixed together on the plate<br>Other: Small Portion Size<br>* Small meal portion size<br>Other: Without Beverage<br>* Meal served without water<br>|
| Experimental: High Variety Small Portion Without Beverage<br>Test meal with food components separated on the plate (high variety) with a small portion of food served without water | Other: High Variety<br>* Meal components are served separately on the plate<br>Other: Small Portion Size<br>* Small meal portion size<br>Other: Without Beverage<br>* Meal served without water<br>|
| Experimental: Low Variety Small Portion With Beverage<br>Test meal with food components mixed together (low variety) with a small portion of food and water | Other: Low variety<br>* Meal components are mixed together on the plate<br>Other: Small Portion Size<br>* Small meal portion size<br>Other: With Beverage<br>* Meal served with water<br>|
| Experimental: High Variety Small Portion With Beverage<br>Test meal with food components separated on the plate (high variety) with a small portion of food and water | Other: High Variety<br>* Meal components are served separately on the plate<br>Other: Small Portion Size<br>* Small meal portion size<br>Other: With Beverage<br>* Meal served with water<br>|
| Experimental: Low Variety Large Portion With Beverage<br>Test meal with food components mixed together (low variety) with a large portion of food and water | Other: Low variety<br>* Meal components are mixed together on the plate<br>Other: Large Portion Size<br>* Large meal portion size<br>Other: With Beverage<br>* Meal served with water<br>|
| Experimental: High Variety Large Portion With Beverage<br>Test meal with food components separated on the plate (high variety) with a large portion of food and water | Other: High Variety<br>* Meal components are served separately on the plate<br>Other: Large Portion Size<br>* Large meal portion size<br>Other: With Beverage<br>* Meal served with water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in intake by weight | Weight (grams) of all meal components consumed | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in energy intake | Energy intake (kilocalories) of all meal components consumed, calculated from weight and energy density | Weeks 1, 2, 3, 4, 5, 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in bite count | The number of bites of food during the meal | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in meal duration | Duration of the meal in minutes | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in mean eating rate | Mean food intake per minute (grams/minute), calculated by dividing meal food intake by meal duration | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in mean bite size | Mean food intake per bite (grams/bite), calculated by dividing meal food intake by bite count | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in sip count | The number of sips of water during the meal | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in mean drinking rate | Mean water intake per minute (grams/minute), calculated by dividing meal water intake by meal duration | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in mean sip size | Mean water intake per sip (grams/sip), calculated by dividing meal water intake by sip count | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in switching between bites and sips | The number of switches between bites and sips during the meal | Weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of pleasantness of the taste of food samples | Measured on a 100-mm visual analogue scale ranging from not at all pleasant (0 mm) to extremely pleasant (100 mm). This will be used to calculate Sensory-Specific Satiety | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of prospective consumption of food samples | Measured on a 100-mm visual analogue scale ranging from none at all (0 mm) to vary large amount (100 mm) how much of [this food] do you want to eat right now?. This will be used to calculate Sensory-Specific Satiety | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of hunger | Measured on a 100-mm visual analogue scale ranging from not at all hungry (0 mm) to extremely hungry (100 mm) | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of thirst | Measured on a 100-mm visual analogue scale ranging from not at all thirsty (0 mm) to extremely thirsty (100 mm) | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of nausea | Measured on a 100-mm visual analogue scale ranging from not at all nauseated (0 mm) to extremely nauseated (100 mm) | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of fullness | Measured on a 100-mm visual analogue scale ranging from not at all full (0 mm) to extremely full (100 mm) | From before the test meal to after the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of prospective consumption of the meal | Measured on a 100-mm visual analogue scale ranging from nothing at all (0 mm) to a large amount (100 mm) in answer to the question 'How much food could you eat right now?'. | At the start of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of the size of the meal compared to participant's usual portion | 100-point visual analog scale ranging from a lot smaller (0 mm) to a lot larger (100 mm) | At the start of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of how filling the participant expects this amount of food to be | 100-point visual analog scale ranging from not at all filling (0 mm) to extremely filling (100 mm) | At the start of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to fullness | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to eating their usual amount | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to eating is no longer a priority | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to there being no food left | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to self-consciousness about amount consumed | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in rating of meal termination due to the food no longer tasting good | 100-point visual analog scale ranging from strongly disagree (0 mm) to strongly agree (100 mm) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in estimation of proportion of meal eaten | 100-point visual analog scale ranging from 0% to 100% | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 | 
| Change in estimation of calories consumed at the meal | Open ended question (number of calories) | At the end of the test meal in weeks 1, 2, 3, 4, 5, 6 |