The objective is to test the accuracy and user satisfaction of the PortionSize™ app and the MyFitnessPal© app during laboratory controlled test meals.

Accurately quantifying food intake is vital to promoting health and reducing chronic disease risk. Food intake encompasses energy intake, nutrient intake (macronutrients, micronutrients, vitamins, minerals), and intake of various food groups (e.g., fruits, vegetables), and thus reflects the nutritional status of individuals. Nutrition affects disease risk, including risk of developing obesity, diabetes, and cancer, all of which negatively affect the United States (U.S). Nonetheless, accurate assessment of food and nutrient intake has remained challenging, despite an improvement in methods. Self report methods, namely food records, are a mainstay of nutritional epidemiology research, with food recall being another popular method. These methods rely on the participant to accurately estimate portion size and, for food recall, remember what was consumed. The accuracy of these methods have been questioned and the problems with human recall have been comprehensively outlined. As a result, there remains a significant need for methods that are sufficiently accurate to provide researchers with good outcome data and to guide health promotion efforts.

The PortionSize™ app was designed by our laboratory to overcome the limitations outlined above, and to guide users to follow specific diets. PortionSize relies on users capturing images of their food selection and waste. Food intake data are immediately provided since the user relies on built in tools, including templates, to estimate portion size. However, despite promising early indications, the PortionSize app's validity has yet to be extensively tested. Determining the accuracy of PortionSize is vital before users can utilize the app to obtain immediate feedback about their food intake. We accordingly aim to test the validity of PortionSize in a controlled laboratory setting. We will also test the validity of the MyFitnessPal© app, which is similar to an electronic food record.

Inclusion Criteria:

• Male or female, age 18-70 years
• Body mass index (BMI) 18.5 - 50
• Ownership of an iPhone model 6s or later, which the participant is willing to use for the study
• Access to Apple ID, password, and email address and willing to use them in the course of the study
• Willing to use data and any accompanying charges as part of study participation
• Willing to be re-contacted for future research and/or follow-up

Exclusion Criteria:

• Center employee
• Any condition or circumstance that could impede study completion

Healthy participants ages 18 to 70 in the Baton Rouge, LA area.

all 42 participants who completed the study

9 months