PortionSize Study 2 Free-Living Evaluation

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 has yet to be fully validated. Determining the accuracy and reliability of PortionSize™ is vital before the app can be used by people to obtain immediate feedback about their food intake. We accordingly aim to test the reliability and validity of PortionSize™ in a semi-controlled free-living environment using food provision, where participants consume pre-weighed food from a cooler and return the plate waste in the cooler. We will also test the reliability and validity of the MyFitnessPal app in the same semi-controlled free-living environment. The accuracy of the apps will also be compared to each other.

Inclusion criteria

Male or female, age 18-62 years

• Body mass index (BMI) 18.5-50 kg/m2
• Subjects who are capable of giving informed consent and complying with all study procedures/requirements.
• 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 during the study
• Willing to use data and any accompanying charges as part of study participation
• Willing to complete all study procedures and adhere to study visit timelines
• Willing to be re-contacted for future research and/or follow-up

Exclusion criteria

• Active cancer diagnosis (excluding some melanomas)
• Have been 6-month weight unstable (gain/loss >10 lbs in last 6 months)
• Undergoing weight loss treatment
• PBRC employee, as previous reviewers argued that they are not representative of the community
• Women who are currently pregnant or breastfeeding (self-reported)
• Diagnosed with an uncontrolled thyroid disorder (controlled = 3 months of medication)
• Have had or plan to have weight loss surgery (gastric band removal may be allowed at PI discretion)
• Allergic to or unwilling to eat study foods provided (exceptions made at the discretion of the PI)
• Consume >28 alcoholic beverages per week
• Anyone severely immunocompromised
• Any condition or circumstance that in the judgement of the PI could interfere with study participation