# Obesity stigma and health behavior: An experimental approach

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2023 · $375,668

## Abstract

PROJECT SUMMARY
Over 70% of U.S. adults are classifiable as overweight or obese, and weight stigma, defined as the negative
attitudes, prejudice, and discrimination directed at heavier individuals, is highly prevalent. Our long-term goal is
to understand and ultimately mitigate the negative behavioral effects of weight stigma that pose risk for obesity
and cardiovascular disease. In order to achieve this goal, we must first gain a fundamental understanding of the
causal processes of weight stigma and how it functions in people’s lives to promote obesity. Therefore, the focus
of this basic experimental study in humans (BESH) is to use an experimental manipulation as a probe in order
to gain a fundamental causal understanding of the obesogenic nature of weight stigma. Much of the available
evidence tying weight stigma to poor health outcomes is observational, precluding conclusions regarding
causality. The few existing experimental studies that can infer causality only assess immediate outcomes in
artificial lab settings. Moreover, the literature has thus far focused on documenting the negative effects of weight
stigma, without attending to resilience factors that could confer protection against them. Therefore, our overall
objectives are to (1) test the central hypothesis that weight stigma causes decrements in health behaviors in
everyday life using ecological momentary assessment (EMA) and actigraphy, and (2) identify resilience factors
that could, in future work, be targeted in weight stigma interventions. The central hypothesis is based on existing
literature and our 8 preliminary studies, which include a study of 2,000 participants census-matched to U.S.
population demographics demonstrating associations between greater weight stigma and binge eating and sleep
disturbance. Our focus on health behaviors is important because behaviors account for 40% of preventable
deaths and are strongly protective against obesity and cardiovascular disease. Moreover, there is evidence that
the COVID-19 pandemic is detrimentally impacting diet, exercise, and sleep. Using a true experimental design,
we will therefore pursue the following aims that capitalize on our deep experience manipulating weight stigma in
laboratory experiments and our demonstrated expertise in ecological momentary assessment and actigraphy
studies. AIM 1: Test the causal effects of weight stigma on diet, physical activity, and sleep in everyday life—we
will randomly assign participants to a weight stigma vs. control manipulation and measure changes health
behaviors in their everyday lives (3-day diet as captured by EMA food diaries, objectively measured physical
activity captured by 24-hour actigraphy, and sleep, captured objectively by overnight actigraphy and subjectively
self-reported sleep measures). AIM 2: Identify resilience factors that confer protection against the causal effects
of weight stigma—we will test moderators drawn from two sources of theory (identity/belongingness and
...

## Key facts

- **NIH application ID:** 10642736
- **Project number:** 5R01HL158555-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** A. Janet Tomiyama
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $375,668
- **Award type:** 5
- **Project period:** 2021-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10642736

## Citation

> US National Institutes of Health, RePORTER application 10642736, Obesity stigma and health behavior: An experimental approach (5R01HL158555-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10642736. Licensed CC0.

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