Exercise-Based Obesity Simulation and Weight Bias

University of Wisconsin, River Falls107 enrolled

Overview

This study examines whether an exercise-based simulation can reduce weight bias and improve professional skills among health professions students. Weight stigma in healthcare settings can negatively affect patient communication, clinical decision-making, and patient engagement in health-promoting behaviors. In this randomized controlled trial, undergraduate health professions students were assigned to one of three groups: (1) a control group completing a communication module and light stretching, (2) an exercise-only group completing treadmill walking, or (3) an exercise group completing treadmill walking while wearing an obesity simulation suit designed to represent additional body weight. The simulation aimed to provide students with an experiential understanding of movement challenges associated with higher body weight. Participants completed assessments at baseline, one week, and eight weeks after the intervention. Outcomes included measures of implicit and explicit weight bias, empathy, clinical decision-making using patient scenarios, professional behavioral intentions, and reflective learning. The purpose of this study is to determine whether a brief experiential intervention can reduce weight bias and improve competencies related to patient-centered and weight-inclusive care in health professions education.

This randomized controlled trial evaluated the impact of an exercise-based obesity simulation on weight bias and professional competencies among undergraduate health professions students. Participants (N = 107) were randomized in a 1:1:1 ratio to one of three conditions: (1) control (professional communication module and low-intensity stretching), (2) moderate-intensity treadmill exercise without simulation, or (3) treadmill exercise while wearing an adjustable obesity simulation suit representing approximately 20% additional body mass. The intervention consisted of a single 30-minute session. Outcomes were assessed at baseline, 1-week follow-up, and 8-week follow-up. The primary outcome was change in implicit weight bias measured using the Weight Implicit Association Test. Secondary outcomes included explicit weight bias (Anti-Fat Attitudes Questionnaire; Fat Phobia Scale), empathy (Jefferson Scale of Empathy - Health Professions Student version), clinical decision-making using structured patient vignettes, behavioral intentions toward future patients, and structured reflective learning. Physiological and perceptual responses during the intervention (heart rate, perceived exertion, discomfort, and affective valence) were also recorded to examine associations between experiential intensity and learning outcomes. The study aims to evaluate whether a brief experiential educational intervention can reduce weight bias and improve empathy and clinical reasoning relevant to weight-inclusive care.

Interventions

Exercise with Obesity Simulation SuitBEHAVIORAL

Participants completed the same 30-minute treadmill protocol as the exercise-only group while wearing an adjustable obesity simulation suit. The suit added approximately 20% of body mass to simulate increased body weight and movement constraints during exercise.

Exercise-onlyBEHAVIORAL

Participants completed a 30-minute treadmill walking session consisting of a 5-minute warm-up (2.5 mph, 0% grade), 20-minute walk (2.5 mph, 6% grade), and 5-minute cool-down. Heart rate and perceived exertion were monitored to ensure moderate-intensity exercise.

ControlBEHAVIORAL

Participants completed a time-matched session consisting of a 10-minute professional communication micro-module (etiquette, active listening, teamwork; no obesity-related content) followed by approximately 20 minutes of low-intensity stretching. The session was designed to control for instructor attention and time without exposure to exercise or obesity simulation.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 30 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Undergraduate student enrolled at the University of Wisconsin-River Falls in a health professions-related program or major * Age 18 years or older * Able to safely participate in moderate-intensity treadmill walking * Cleared to participate based on the American College of Sports Medicine (ACSM) preparticipation screening algorithm * Willing and able to provide informed consent and complete study assessments at baseline, 1-week, and 8-week follow-up Exclusion Criteria: * Contraindications to exercise or treadmill walking based on ACSM screening (e.g., symptoms suggestive of cardiovascular, metabolic, or renal disease without medical clearance) * Current or past eating disorder (self-reported) * Body dysmorphic disorder (self-reported) * Recent weight-related trauma within the past 12 months (self-reported) * Any condition or injury that would make treadmill walking unsafe, as determined during screening

Outcomes

Primary Outcomes

Change in Implicit Weight Bias

Implicit weight bias was assessed using the Weight Implicit Association Test (IAT). D-scores reflect the strength of automatic pro-thin/anti-fat associations. Higher positive scores indicate stronger implicit anti-fat bias. The primary outcome is the change in IAT D-score from baseline to 8-week follow-up.

Time frame: Baseline, 1-week, and 8 weeks post-intervention

Secondary Outcomes

Explicit Weight Bias

Explicit weight bias was assessed using two validated self-report instruments: Anti-Fat Attitudes Questionnaire (AFA) (Crandall, 1994), which includes three subscales: Dislike (7 items; score range: 1-7); Fear of Fat (3 items; score range: 1-7); Willpower Attributions (3 items; score range: 1-7). Subscale scores are calculated as the mean of items within each domain. Higher scores indicate stronger negative attitudes toward individuals with obesity. Fat Phobia Scale-Short Form (FPS-SF) (Bacon et al., 2001) is a 14-item semantic differential scale. Scores range from 1 to 5, with higher scores indicating stronger endorsement of negative obesity-related stereotypes.

Time frame: Baseline, 1 week, and 8 weeks post-intervention

Clinical Decision-Making Quality

Clinical reasoning will be assessed using structured weight-related patient vignettes developed for health professions education contexts. For each vignette, participants rate agreement with patient-centered and stigmatizing response options on a 7-point Likert scale (1 = strongly disagree; 7 = strongly agree). A composite score is calculated as: Mean patient-centered rating minus mean stigmatizing rating.

Time frame: Baseline, 1 week, and 8 weeks post-intervention

Reflective Learning Quality

Structured written reflections will be evaluated using a rubric based on transformative learning theory, assessing four dimensions: Disorienting Dilemma Recognition; Critical Reflection; Perspective Transformation; Integration Planning. Each dimension is scored from 0 to 3. The composite score (sum of four domains) ranges from 0 to 12.

Time frame: 1 week post-intervention only