ObesityNCT05402137
Daily Habits & Consumer Preferences Study
A study testing Weight stigma intervention in people with Obesity, run by University of California, Los Angeles at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Obesity
- What is being tested?
- Weight stigma intervention
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 330 participants
- Where
- 1 siteUnited States
- Study dates
- 28 Apr 2022to 3 Aug 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 18+
- English-speaking
- BMI greater than or equal to 28
Who cannot join
- Major mental disorder including eating disorder, mood disorder, schizophrenia, PTSD
- Recent (<1 year) diagnosis of major physical conditions that limit physical movement
- Recent (<1 year) diagnosis of sleep disorder
- Allergy to any of the foods in the food buffet
Trial locations and contacts
1 site in 1 country.
United States1 site
University of California, Los Angeles
Los Angeles, California, 90034
About this study
Official title: Obesity Stigma and Health Behavior: An Experimental Approach
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
- Being tested
- Weight stigma intervention
- Keywords
- Weight Prejudice, Sleep, Eating, Exercise, Ecological Momentary Assessment, Actigraphy, Diet Records
- Medical subject headings
- Obesity, Weight Prejudice, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Weight stigma interventionBehavioural
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.
| Study group | Role | What they receive |
|---|---|---|
| Experimental (Weight Stigma) Arm | Experimental | 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. Receives: Behavioral: Weight stigma intervention |
| Control Arm | No intervention | 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hyperpalatable Food Intake
Hyperpalatable food intake will initially be measured in grams and then converted into kilocalories. The food will consist of the following items: chocolate chip cookies, M\&Ms, potato chips, and Sprite. These foods were chosen because processed foods, added sugars, refined grains, starchy vegetables, and sugar sweetened beverages are foods to avoid according to the 2019 American Diabetes Association Nutrition Consensus Report and are high in carbohydrates and glycemic index.
Measured: Hyperpalatable food intake will be measured directly after the intervention, on average 10 minutes later.
Change in Self-reported Dietary Intake
Dietary intake data for food recalls will be collected and analyzed using the Automated Self-Administered 24-hour (ASA24) Dietary Assessment Tool developed by the National Cancer Institute, Bethesda, MD. The primary eating outcome for the food diaries will be kilocalories.
Measured: Change in self-reported dietary intake will be assessed by measuring self-reported dietary intake 72 hours before the intervention as part of the baseline, and 72 hours after the intervention.
Change in Physical Activity
Physical activity, quantified as Metabolic Equivalent of Task (MET) units, will be assessed using ActivPAL4 actigraphs.
Measured: Change in physical activity will be assessed by measuring physical activity for 72 hours before the intervention as part of the baseline, and 72 hours after the intervention.
Change in Sleep Duration
Change in sleep duration will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute.
Measured: Change in sleep duration will be assessed by measuring sleep duration for three days before the intervention as part of the baseline, and three days after the intervention.
Change in Self-reported Sleep Quality
Participants will respond to a single item assessing past night's sleep quality, with response options ranging from 1 (very bad) to 4 (very good). Change in subjective sleep quality will be calculated by taking the difference of the item score pre- and post-intervention. The possible minimum for change in self-reported sleep quality is -3 and the possible maximum is 3. In this difference score, higher scores indicate improvements in sleep quality from baseline to post.
Measured: Change in self-reported sleep quality will be assessed by measuring self-reported sleep quality during the mornings of the first 72 hour baseline period before the intervention, and in the mornings of the 72 hour period after the intervention.
Change in Sleep Onset Latency
Change in sleep onset latency will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute. Sleep onset is operationalized as after 10 consecutive minutes of D ≤ 40 (as D > 40 indicates participants are awake).
Measured: Change in sleep onset latency will be assessed by measuring sleep onset latency for three days before the intervention as part of the baseline, and three days after the intervention.
Change in Sleep Efficiency
Change in sleep efficiency will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute. The possible minimum value is -100 and the possible maximum value is 100. Higher scores indicate better sleep efficiency.
Measured: Change in sleep efficiency will be assessed by measuring sleep efficiency for three days before the intervention as part of the baseline, and three days after the intervention.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Jun 2022
- Study start28 Apr 2022
- Primary completion3 Aug 2024
- Study completion3 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 330 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Collaborators
- University of California, San Francisco, Miami University
- Responsible party
- Principal investigator, A. Janet Tomiyama, University of California, Los Angeles
- Investigators
- A. Janet Tomiyama, Ph.D., Principal investigator, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05402137
- Sponsor's protocol ID
- 21-000460
- Status last verified
- Oct 2025
- First submitted
- 25 May 2022
- Last updated
- 20 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Obesity Stigma and Health Behavior: An Experimental Approach
- ClinicalTrials.gov ID
- NCT05402137
- Acronym / sponsor ID
- 21-000460
- Conditions
- Obesity
- Keywords
- Weight Prejudice, Sleep, Eating, Exercise, Ecological Momentary Assessment, Actigraphy, Diet Records
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 330 participants (actual)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Collaborators
- University of California, San Francisco, Miami University
- Study start
- 28 Apr 2022 (actual)
- Primary completion
- 3 Aug 2024 (actual)
- Study completion
- 3 Aug 2024 (actual)
- First posted
- 2 Jun 2022 (actual)
- Results
- Posted 20 Jan 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Experimental (Weight Stigma) Arm | Experimental | Behavioral: Weight stigma interventionParticipants 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. |
| Control Arm | No intervention | –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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age 18+
- English-speaking
- BMI greater than or equal to 28
Key exclusion criteria (4 listed)
- Major mental disorder including eating disorder, mood disorder, schizophrenia, PTSD
- Recent (<1 year) diagnosis of major physical conditions that limit physical movement
- Recent (<1 year) diagnosis of sleep disorder
- Allergy to any of the foods in the food buffet
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Weight stigma interventionThose 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. | Behavioural | Experimental (Weight Stigma) Arm |
Primary outcome
Hyperpalatable Food Intake
Time frame: Hyperpalatable food intake will be measured directly after the intervention, on average 10 minutes later.
Hyperpalatable food intake will initially be measured in grams and then converted into kilocalories. The food will consist of the following items: chocolate chip cookies, M\&Ms, potato chips, and Sprite. These foods were chosen because processed foods, added sugars, refined grains, starchy vegetables, and sugar sweetened beverages are foods to avoid according to the 2019 American Diabetes Association Nutrition Consensus Report and are high in carbohydrates and glycemic index.
Change in Self-reported Dietary Intake
Time frame: Change in self-reported dietary intake will be assessed by measuring self-reported dietary intake 72 hours before the intervention as part of the baseline, and 72 hours after the intervention.
Dietary intake data for food recalls will be collected and analyzed using the Automated Self-Administered 24-hour (ASA24) Dietary Assessment Tool developed by the National Cancer Institute, Bethesda, MD. The primary eating outcome for the food diaries will be kilocalories.
Change in Physical Activity
Time frame: Change in physical activity will be assessed by measuring physical activity for 72 hours before the intervention as part of the baseline, and 72 hours after the intervention.
Physical activity, quantified as Metabolic Equivalent of Task (MET) units, will be assessed using ActivPAL4 actigraphs.
Change in Sleep Duration
Time frame: Change in sleep duration will be assessed by measuring sleep duration for three days before the intervention as part of the baseline, and three days after the intervention.
Change in sleep duration will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute.
Change in Self-reported Sleep Quality
Time frame: Change in self-reported sleep quality will be assessed by measuring self-reported sleep quality during the mornings of the first 72 hour baseline period before the intervention, and in the mornings of the 72 hour period after the intervention.
Participants will respond to a single item assessing past night's sleep quality, with response options ranging from 1 (very bad) to 4 (very good). Change in subjective sleep quality will be calculated by taking the difference of the item score pre- and post-intervention. The possible minimum for change in self-reported sleep quality is -3 and the possible maximum is 3. In this difference score, higher scores indicate improvements in sleep quality from baseline to post.
Change in Sleep Onset Latency
Time frame: Change in sleep onset latency will be assessed by measuring sleep onset latency for three days before the intervention as part of the baseline, and three days after the intervention.
Change in sleep onset latency will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute. Sleep onset is operationalized as after 10 consecutive minutes of D ≤ 40 (as D > 40 indicates participants are awake).
Change in Sleep Efficiency
Time frame: Change in sleep efficiency will be assessed by measuring sleep efficiency for three days before the intervention as part of the baseline, and three days after the intervention.
Change in sleep efficiency will be assessed using an Actiwatch-2 (Philips Respironics). Data will be captured in 30-second epochs and validated. Actiware 6.0.9 software algorithms will be used to estimate sleep parameters with the following sleep/wake algorithm: D = A-2*(1/25) + A1*(1/5) + A*(1) + A + 1*(1/5) + A + 2*(1/25), where AX = accelerometer activity for that minute. The possible minimum value is -100 and the possible maximum value is 100. Higher scores indicate better sleep efficiency.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
A. Janet Tomiyama, Ph.D. principal investigator
University of California, Los Angeles
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Weight stigma intervention in people with Obesity, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 20 Jan 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hyperpalatable Food Intake (time frame: Hyperpalatable food intake will be measured directly after the intervention, on average 10 minutes later.). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jan 2026.