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

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.

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

Healthy participants ages 18 to 65 in the Baton Rouge, LA area.

3 months (during the study period)

This study involved no greater than minimal risk.