Daily Habits & Consumer Preferences Study

NCT ID: NCT05402137

Last Updated: 2026-01-20

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 330 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-04-28
• Study Completion Date: 2024-08-03

Brief Summary

The study will use a between-subjects design in a sample of individuals with BMI greater than or equal to 28 from the Los Angeles community (N=330). Participants will be randomly assigned to a weight stigma vs. control manipulation. Changes to the following health behaviors will be subsequently measured in their everyday lives: 3-day diet as captured by ecological momentary assessment (EMA) food diaries, objectively measured eating of obesogenic foods, objectively measured physical activity captured by 24-hour actigraphy, and sleep, captured objectively by overnight actigraphy and subjectively self-reported sleep measures. The investigators hypothesize that weight stigma causes decrements in health behaviors (e.g., sleep, eating, and physical activity) in everyday life.

Conditions

Obesity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: SINGLE

Study Groups

Experimental (Weight Stigma) Arm

Participants undergoing the experimental (Weight Stigma) arm are exposed to an interaction partner (a trained confederate) who endorses anti-fat attitudes. Prior to their interaction, participants exchange a "Getting to Know You Questionnaire" with the confederate, where the confederate endorses anti-fat attitudes. During their interaction with the confederate, participants are told they will be completing consumer rating tasks with another participant in the study. During the ostensible consumer rating task, participants in the experimental condition rate items such as a diet magazine, body sunscreen, running shoes, and a size small T-shirt labeled as size large to bolster the weight stigma manipulation.

Group Type: EXPERIMENTAL

Weight stigma intervention

Intervention Type: BEHAVIORAL

Those undergoing the weight stigma manipulation will be exposed to an interaction partner (a trained confederate) who will endorse anti-fat attitudes. The purpose of this interaction is to examine the causal effects of weight stigma on eating behaviors, physical activity, and sleep.

Control Arm

Participants undergoing the control arm are also exposed to an interaction partner (a trained confederate) who does not endorse anti-fat attitudes. Prior to their interaction, participants exchange a "Getting to Know You Questionnaire" with the confederate; however, the confederate does not endorse anti-fat attitudes. During their interaction with the confederate, participants are told they will be completing consumer rating tasks with another participant in the study. During the ostensible consumer rating task, participants in the control condition rate items such as an interior design magazine, face sunscreen, regular (non-running) shoes, and a size large T-shirt correctly labeled as size large to avoid weight stigma.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Weight stigma intervention

Those undergoing the weight stigma manipulation will be exposed to an interaction partner (a trained confederate) who will endorse anti-fat attitudes. The purpose of this interaction is to examine the causal effects of weight stigma on eating behaviors, physical activity, and sleep.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

1. Age 18+

2. English-speaking

3. BMI greater than or equal to 28

Exclusion Criteria

1. Major mental disorder including eating disorder, mood disorder, schizophrenia, PTSD

2. Recent (<1 year) diagnosis of major physical conditions that limit physical movement

3. Recent (<1 year) diagnosis of sleep disorder

4. Allergy to any of the foods in the food buffet

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of California, San Francisco

OTHER

Sponsor Role: collaborator

Miami University

OTHER

Sponsor Role: collaborator

University of California, Los Angeles

OTHER

Sponsor Role: lead

Responsible Party

A. Janet Tomiyama

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

A. Janet Tomiyama, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

University of California, Los Angeles

Locations

University of California, Los Angeles

Los Angeles, California, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Document Type: Informed Consent Form

View Document

Other Identifiers

21-000460

Identifier Type: -

Identifier Source: org_study_id