This study examines how accurately adults report their food intake using a common self-report method called the 24-hour dietary recall. While this method is widely used in nutrition research, it often leads to underreporting, especially among individuals with overweight or obesity. However, it is unclear if specific foods are more likely to be misreported.

To address this, participants will be served a controlled meal containing both simple foods (e.g., fruit snacks, saltine crackers, cookies, and a coke soft drink) and mixed dishes (e.g., chicken salad, macaroni and cheese with peas). Each food item will be precisely weighed before and after consumption. The following day, participants will complete an online 24-hour recall, and the process will be repeated one week later.

The study will compare reported intake to actual intake to assess accuracy and determine whether underreporting is more common for mixed dishes. It will also explore whether reporting accuracy is influenced by body weight, gender, or race. Findings from this research may improve the understanding of self-report limitations and support the development of more accurate dietary assessment tools.

This prospective observational cohort study with repeated measures investigates the accuracy of self-reported dietary intake using the 24-hour dietary recall method, specifically the Automated Self-Administered 24-hour Dietary Assessment Tool (ASA-24). Research has consistently shown that individuals underreport energy intake using self-report tools, particularly those with overweight or obesity. However, there is limited understanding of which types of foods are most prone to misreporting and whether such tendencies are consistent across time or demographic groups.

To address these gaps, this study uses a controlled feeding protocol in which participants consume a standardized lunch consisting of two mixed dishes (chicken salad and macaroni and cheese with peas) and single-item foods (e.g., fruit snacks, saltine crackers, cookies, and a coke soft drink). All foods are weighed precisely before and after consumption to the nearest 0.01g. The following day, participants complete an online 24-hour dietary recall using ASA-24. This process is repeated one week later to assess reproducibility of reporting patterns.

The primary outcome is the portion-size reporting difference between actual and reported intake for each food item. Secondary outcomes include whether mixed dishes are more inaccurately reported than discrete foods, and whether underreporting is consistent across both sessions. Additional analyses will evaluate whether underreporting varies by BMI category, gender, or race.

Participants (N=65) are adults aged 18-65 recruited from the Texas Tech University community using flyers, email announcements, and word of mouth. Inclusion criteria include availability to attend lunch visits and complete online recalls. Exclusion criteria include food allergies or aversions to the test meal.

Inclusion Criteria:

• Able to attend the test site for a meal at least two times.

Exclusion Criteria:

• Any aversions to the test meal (including allergies)

The population will include anyone eligible based on the inclusion and exclusion criteria. Those who are 18-65 years of age are eligible, there are no other restrictions.