The PortionSize Smartphone App Pilot (PS Pilot)

Study Overview
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Brief Summary
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The objective is to examine the preliminary validity, reliability and perceived participant satisfaction of the PortionSize app.

Detailed Description
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Overweight and obesity are a burgeoning public health concern, yet only a small minority of smartphone apps that claim to facilitate healthy eating and weight loss incorporate evidence-based principles. Such innovations are important as humans fundamentally cannot accurately estimate portion size. Indeed, portion size estimation errors account for  50% of the error in self-reported food intake, and data from our laboratory has demonstrated that extensive training results in only modest improvements in portion size estimation accuracy and that portion size estimates remain inaccurate. Our long-term goal is to create simple and accessible interventions that assist individuals with weight control. In particular, we aim to provide easy-to-use phone apps that allow participants to monitor the portion sizes of the foods they consume. These apps guide participants on appropriate portion sizes and provide recommendations of food groups that should be consumed. To that end, we have developed the PortionSize app. We propose to improve the accuracy of portion size measurement, as it is poorly determined by self-report measures. This will occur via the development of the PortionSize smartphone app and this pilot study will test the usability as well as preliminary validity and reliability of the app functionality.

Official Title
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Pilot Validation of an App to Estimate and Manage Portion Size: The PortionSize Smartphone App

Conditions
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Dietary Habits

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI 18.5-45 kg/m2 based upon self-reported height and weight Have an iPhone and an operable Apple ID, password, and email address and is willing to use these to collect data during the study, acknowledging that data usage, and associated charges, are a result of study participation Exclusion Criteria: For females, pregnancy or breast feeding Currently diagnosed with an eating disorder Disease that severely affects metabolism, including diabetes, hypercholesterolemia, or dyslipidemia Has gained or lost more than 10 lbs in the last 3 months PBRC faculty/staff member Has suffered serious mental illness that has resulted in serious functional impairment and has substantially interfered with one's life activities within the last 5 years Any other medical, psychiatric, or behavioral factors in the judgment of the Principle Investigator that may interfere with study participation or the ability to follow the protocol

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Validity of portion size at estimating energy intake | Compared measurements from PortionSize to weighed values in the lab. | August - December 2020 | 
| Reliability of portion size at estimating energy intake | Quantify the reliability of app measurements over time in free-living conditions. | August - December 2020 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| User satisfaction | Participant ratings of the PortionSize App | August - December 2020 |