About

Bess H. Marcus is a Professor of Behavioral and Social Sciences and Dean of the Brown University School of Public Health. She is a clinical health psychologist with over 25 years of research experience focused on physical activity behavior. Dr. Marcus has published more than 250 papers and book chapters, as well as three books on this topic. Her work includes developing assessment instruments to measure psychosocial mediators of physical activity and creating low-cost interventions to promote physical activity in community, workplace, and primary care settings. She contributed to national recommendations for physical activity and was a contributing author to the 1996 Surgeon General's Report on Physical Activity and Health.

Research topics

• Medicine
• Internal medicine
• Physical therapy
• Nursing
• Gerontology
• Psychiatry
• Physical medicine and rehabilitation
• Obstetrics
• Psychology

Selected publications

• Collaborative Research at the Brown University School of Public Health: An Introduction.

  PubMed · 2026-04-01

  article1st authorCorresponding
  Publisher

• Sleep as an effect modifier for physical activity intervention efficacy: secondary analysis of data from two randomized controlled trials

  Research Square · 2026-03-02

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• Parenting Training Plus Behavioral Treatment for Children With Obesity

  JAMA Network Open · 2025-05-05 · 6 citations

  articleOpen access

  Importance: Family-based behavioral treatment (FBT) is recommended for childhood obesity treatment; however, it is not effective for all families. Since parenting training (PT) has been associated with healthy weight and eating behaviors, intensive PT may augment delivery of behavior change strategies and improve child weight loss outcomes. Objective: To compare the efficacy of child overweight or obesity treatment that adds intensive PT to standard FBT with the efficacy of FBT alone. Design, Setting, and Participants: This 2-arm randomized clinical trial (Reinforced, Enhanced, Families, Responsibility, Education, Support, and Health [ReFRESH]) conducted from April 2017 to November 2022 at an academic center in San Diego, California, included children aged 7 to 12 years with overweight or obesity (body mass index [BMI]≥85th to <99.9th percentile) and one of their parents. Interventions: Parent-child dyads were randomized 1:1 to the intervention group, which received FBT plus PT, or the control group, which received FBT alone. Both groups received twenty 60-minute sessions over 6 months with separate parent and child groups led by staff and nine 20-minute behavior change coaching sessions. The FBT plus PT group sessions incorporated additional intensive parenting skills training in an interactive format. Main Outcomes and Measures: The primary outcome was change from baseline in child BMI z score and BMI as a percentage of the 95th BMI percentile (BMIp95) after treatment (month 6) and at 6- and 12-month follow-up. Secondary outcomes included the proportion of children who attained clinically meaningful weight loss (ie, reduction of ≥0.20 BMI z score units) and intervention dropout rates. Intention-to-treat analysis was conducted using linear mixed models and logistic regression. Results: A total of 140 parent-child dyads were included, with 70 in each treatment arm. Mean (SD) child age was 9.91 (1.54) years, and baseline BMI z score was 2.28 (0.80); 71 children (50.7%) were female. There were no significant between-group differences in BMI z score or BMIp95 after treatment or at the follow-up time points. Both groups had significant decreases in weight status after treatment (combined BMI z score: β, -0.14 [95% CI, -0.21 to -0.07]; P < .001; combined BMIp95: β, -3.46 [95% CI, -5.41 to -1.51]; P < .001). More children in the FBT plus PT arm compared with the FBT arm had a reduction of at least 0.20 BMI z score units (34 [48.6%] vs 22 [31.4%]; P = .01) after treatment (adjusted odds ratio, 2.10 [95% CI, 1.01-4.47]). Both treatments were well accepted, with no between-group differences in risk of dropout (hazard ratio, 1.01 [95% CI, 0.72-1.43]). Conclusions and Relevance: In this randomized clinical trial examining the effect of parenting training on child weight status, there were no significant differences in weight status between groups; children in both groups had a significant reduction in weight status. However, more children had clinically meaningful weight loss in the FBT plus PT group. Further work is needed to determine factors associated with treatment response and changes in parenting skills. Trial Registration: ClinicalTrials.gov Identifier: NCT02976636.

  PublisherOA PDFDOI

• Impact of a Lifestyle Intervention Among Latina Women on Infant Birth and Anthropometric Measures: Pooled Analyses of 2 Randomized Controlled Trials

  Journal of Physical Activity and Health · 2025-04-29

  article

  BACKGROUND: To assess the impact of a pregnancy and postpartum culturally modified, motivationally targeted, individually tailored intervention on infant outcomes among Latinas. METHODS: We conducted a pooled analysis of 2 randomized controlled trials in Western Massachusetts: Estudio Parto (collected 2013-2017, analyzed 2018-2020, n = 203) and Proyecto Mamá (data collected 2014-2020, analyzed 2021-2022, n = 141) focused on pregnant Latinas (predominantly Puerto Rican) with abnormal glucose tolerance and prepregnancy body mass index in the overweight/obese range, respectively. Women were randomized in pregnancy to a Lifestyle Intervention (n = 167) focusing on healthy exercise and diet or to a comparison Health and Wellness Intervention (n = 177) with no mention of exercise or diet. The primary outcomes in both studies were birth weight, gestational age, birth weight-for-gestational-age z score, low birth weight, preterm birth, small-for-gestational-age, large for gestational age, macrosomia). Proyecto Mamá also assessed infant anthropometrics (ie, weight, length, sum and ratio of skin fold thickness, ponderal index) at 6 weeks of age. We used linear regression for continuous outcomes and logistic regression for dichotomous outcomes. RESULTS: In modified intent-to-treat analyses, we observed no statistically significant impact of the Lifestyle Intervention on infant outcomes or anthropometric measures. For example, there was no difference in odds of small-for-gestational-age between intervention arms (odds ratio = 1.29; 95% confidence interval, 0.60-2.76). CONCLUSIONS: In these randomized trials among pregnant Latina women, we found that a culturally modified, individually tailored Lifestyle Intervention did not lead to a significant difference in infant birth weight outcomes or anthropometric measures when compared to the Health and Wellness control arm.

  PublisherDOI

• A Multiple Technology–Based Physical Activity Intervention for Latina Adolescents: Results From the Chicas Fuertes Randomized Controlled Trial

  JMIR mhealth and uhealth · 2025-10-17 · 1 citations

  articleOpen access

  Background: Latina adolescents report low levels of moderate-vigorous physical activity (MVPA) and high lifetime risk of lifestyle-related diseases. There is a lack of MVPA interventions targeted at this demographic despite documented health disparities. Given their high rates of mobile technology use, interventions delivered through mobile devices may be effective for this population. Objective: This paper examines the efficacy of the Chicas Fuertes intervention in increasing MVPA across 6 months in Latina adolescents. Methods: Participants were Latina adolescents (aged 13-18 years) in San Diego County who reported being underactive (<150 min/wk of MVPA). All participants received a wearable fitness tracker (Fitbit Inspire HR); half were randomly assigned to also receive the multimedia intervention. Intervention components included a personally tailored website, personalized texting based on Fitbit data, and social media. The primary outcome was change in minutes of weekly MVPA from baseline to 6 months, measured by ActiGraph accelerometers and the 7-Day Physical Activity Recall Interview. Changes in daily steps using Fitbit devices were also examined to test intervention efficacy. Results: Participants (N=160) were 15.85 (SD 1.71) years old on average, and mostly second generation in the United States. For ActiGraph-measured MVPA, participants in the intervention group (n=83) increased from a median of 0 (IQR 0-24) minutes/week at baseline to 64 (IQR 19-72) minutes/week at 6 months compared to control participants, who showed increases from a median of 0 (IQR 0-26) at baseline to 41 (IQR 7-76) minutes/week at 6 months (P=.04). Self-reported MVPA increased in the intervention group from a median of 119 (IQR 62.5-185) minutes/week at baseline to 147 (IQR 96-181) minutes/week at 6 months compared to control participants, who showed increases from a median of 120 (IQR 48.8-235) at baseline to 124 (IQR 100-169) minutes/week at 6 months (P=.03). Steps also increased in both groups, with the intervention group showing significantly greater increases (P=.03). Conclusions: This intervention was successful in using a tailored technology-based strategy to increase MVPA in Latina adolescents and provides a promising approach for addressing a key health behavior. Given the scalable technology used, future studies should focus on broad-scale dissemination to address health disparities.

  PublisherDOI

• A Physical Activity Intervention for High-Risk Mothers whose Children Play Sports: Content Analysis of Exit Interviews (Preprint)

  2025-11-04

  articleOpen access

  <sec> <title>UNSTRUCTURED</title> Background: Mothers, especially those with low socioeconomic status and minoritized identities, encounter barriers to participating in physical activity (PA), a behavior that improves health outcomes. Moms on the Move (MOMs) is a community-based intervention developed to address the PA barriers endorsed by low income Black and Hispanic mothers. This program offered in-person group PA sessions held during children’s sports practices, goal-setting calls, and individually-tailored and motivation-matched materials. Objective: Participants’ engagement and satisfaction with the program, as well as perceived benefits and barriers, were explored. Methods: Exit interviews of 19 participants (58% Black or Hispanic, 42% with an annual household income &lt; $40,000) who completed the MOMs pilot interventions were analyzed with directed content analysis. Results: Participants were generally satisfied with the program, noting benefits including increased motivation to maintain PA beyond the length of the program. Barriers included scheduling conflicts and inclement weather. Three emergent themes framed participants’ evaluation of program success: accountability, accessibility, and ability. Accountability referred to group support that facilitated motivation. Accessibility was described as the appreciation for resources provided by the intervention program, including the provision of exercise equipment. Finally, participants discussed how their shared identity with other mothers increased their sense of ability (or self-efficacy) to engage in PA, which was especially true for participants who described little to no engagement in PA prior to the intervention. Conclusions: Findings from this study support the integration of in-person group PA interventions delivered during youth sports practices for predominantly low-income, Black and Hispanic mothers and women caretakers. </sec>

  PublisherDOI

• Costs and Cost-Effectiveness at 12 and 24 Months of an Enhanced Web-Based Physical Activity Intervention for Latina Adults: Secondary Analysis of a Randomized Controlled Trial

  Journal of Medical Internet Research · 2025-11-25

  articleOpen accessSenior author

  BACKGROUND: We previously established the efficacy and cost-effectiveness of a web-based physical activity (PA) intervention for Latina adults, which increased PA, but few participants met PA guidelines, and long-term maintenance was not examined. A new version with enhanced intervention features was found to outperform the original intervention in long-term guideline adherence. OBJECTIVE: This study aimed to determine the costs and cost-effectiveness of the enhanced multitechnology PA intervention compared to the original web-based intervention in increasing minutes of activity and adherence to guidelines. METHODS: Latina adults (N=195) were randomly assigned to receive a Spanish-language, individually tailored web-based PA intervention (original) or the same intervention with additional phone calls and interactive SMS text messaging (enhanced). PA was measured at baseline, 12 months (end of active intervention), and 24 months (end of tapered maintenance) using self-report (7-day PA recall interview) and ActiGraph accelerometers. Costs were estimated from a payer perspective and included all features needed to deliver the intervention, including staff, materials, and technology. Cost-effectiveness was calculated as the cost per additional minute of PA added over the intervention and the incremental cost-effectiveness ratios of each additional person meeting guidelines. RESULTS: At 12 months, the costs of delivering the interventions were US $16 per person per month in the enhanced arm and US $13 per person per month in the original arm. These costs decreased to US $14 and US $8 at 24 months, respectively. At 12 months, each additional minute of self-reported activity in the enhanced group cost US $0.09 compared to US $0.11 in the original group (US $0.19 vs US $0.16 for ActiGraph), with incremental costs of US $0.05 per additional minute in the enhanced group beyond the original group. At the end of the maintenance period (24 mo), costs per additional minute decreased to US $0.06 and US $0.05 (US $0.12 vs US $0.10 for ActiGraph), with incremental costs of US $0.08 per additional minute in the enhanced group (US $0.20 for ActiGraph). Costs of meeting PA guidelines at 12 months were US $705 in the enhanced group compared to US $503 in the original group and increased to US $812 and US $601 at 24 months, respectively. The incremental cost-effectiveness ratio for meeting guidelines at 24 months was US $1837 (95% CI US $730.89-US $2673.89) per additional person in the enhanced group compared to the original group. CONCLUSIONS: The enhanced intervention was more expensive but yielded better long-term maintenance of activity, costing US $1837 per extra person meeting guidelines beyond those in the original group. Both conditions were low cost relative to other medical interventions. The enhanced intervention may be preferable in populations at high risk, where more investment in meeting guidelines could yield more cost savings. TRIAL REGISTRATION: ClinicalTrials.gov NCT03491592; https://clinicaltrials.gov/study/NCT03491592. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s13063-022-06575-4.

  PublisherDOI

• 1336P Trends and efficacy of definitive radiotherapy regimens for locally advanced head and neck cancer in elderly patients: A population-based analysis by the German cancer registry group

  Annals of Oncology · 2025-09-01

  article
  PublisherDOI

• Costs and Cost-Effectiveness at 12 and 24 Months of an Enhanced Web-Based Physical Activity Intervention for Latina Adults: Secondary Analysis of a Randomized Controlled Trial (Preprint)

  2025-04-29

  preprintOpen accessSenior author

  <sec> <title>BACKGROUND</title> We previously established the efficacy and cost-effectiveness of a web-based physical activity (PA) intervention for Latina adults, which increased PA, but few participants met PA guidelines, and long-term maintenance was not examined. A new version with enhanced intervention features was found to outperform the original intervention in long-term guideline adherence. </sec> <sec> <title>OBJECTIVE</title> This study aimed to determine the costs and cost-effectiveness of the enhanced multitechnology PA intervention compared to the original web-based intervention in increasing minutes of activity and adherence to guidelines. </sec> <sec> <title>METHODS</title> Latina adults (N=195) were randomly assigned to receive a Spanish-language, individually tailored web-based PA intervention (original) or the same intervention with additional phone calls and interactive SMS text messaging (enhanced). PA was measured at baseline, 12 months (end of active intervention), and 24 months (end of tapered maintenance) using self-report (7-day PA recall interview) and ActiGraph accelerometers. Costs were estimated from a payer perspective and included all features needed to deliver the intervention, including staff, materials, and technology. Cost-effectiveness was calculated as the cost per additional minute of PA added over the intervention and the incremental cost-effectiveness ratios of each additional person meeting guidelines. </sec> <sec> <title>RESULTS</title> At 12 months, the costs of delivering the interventions were US $16 per person per month in the enhanced arm and US $13 per person per month in the original arm. These costs decreased to US $14 and US $8 at 24 months, respectively. At 12 months, each additional minute of self-reported activity in the enhanced group cost US $0.09 compared to US $0.11 in the original group (US $0.19 vs US $0.16 for ActiGraph), with incremental costs of US $0.05 per additional minute in the enhanced group beyond the original group. At the end of the maintenance period (24 mo), costs per additional minute decreased to US $0.06 and US $0.05 (US $0.12 vs US $0.10 for ActiGraph), with incremental costs of US $0.08 per additional minute in the enhanced group (US $0.20 for ActiGraph). Costs of meeting PA guidelines at 12 months were US $705 in the enhanced group compared to US $503 in the original group and increased to US $812 and US $601 at 24 months, respectively. The incremental cost-effectiveness ratio for meeting guidelines at 24 months was US $1837 (95% CI US $730.89-US $2673.89) per additional person in the enhanced group compared to the original group. </sec> <sec> <title>CONCLUSIONS</title> The enhanced intervention was more expensive but yielded better long-term maintenance of activity, costing US $1837 per extra person meeting guidelines beyond those in the original group. Both conditions were low cost relative to other medical interventions. The enhanced intervention may be preferable in populations at high risk, where more investment in meeting guidelines could yield more cost savings. </sec> <sec> <title>CLINICALTRIAL</title> ClinicalTrials.gov NCT03491592; https://clinicaltrials.gov/study/NCT03491592 </sec> <sec> <title>INTERNATIONAL REGISTERED REPORT</title> RR2-10.1186/s13063-022-06575-4 </sec>

  PublisherDOI

• Guided Self-Help vs Group Treatment for Children With Obesity: A Randomized Clinical Trial

  PEDIATRICS · 2025-01-29

  articleOpen access

  BACKGROUND AND OBJECTIVES: Family-based behavioral treatment (FBT) for children with obesity is provided in weekly parent and child groups over 6 months. A guided self-help FBT program (gshFBT) is provided to the dyad in short meetings. Both interventions provide the same content; however, gshFBT provides this content in less time (FBT = 23 hours, gshFBT = 5.3 hours). This study aimed to evaluate whether gshFBT is noninferior to FBT on child weight loss and cost-effectiveness. METHODS: 150 children aged between 7.0 and 12.9 years with a BMI between the 85th and 99.9th percentile and their parent were recruited and randomized to a 6-month program of gshFBT (n = 75) or FBT (n = 75) and were followed 12 months post-treatment. RESULTS: A total of 150 children (mean age = 10.1 years, 49% female, mean BMIz = 2.09) and their parent (mean age = 41.5 years, 87% female, 45% Hispanic, 37% White non-Hispanic, 9.7% Asian, 4.8% Black, 7.3% other) were recruited from the San Diego Metropolitan area. Joint LME models showed that gshFBT was noninferior to FBT on child weight loss (ΔBMIz = -0.02 [90% credible interval [CI] -0.08-0.05, P = .65]; ΔBMIp95% = -1.57 [90% CI -4.46-1.31, P = .28]) and cost less (cost/dyad gshFBT = $1498; FBT = $2775). CONCLUSION: The gshFBT program provided similar weight losses for children with less contact hours and with lower cost than FBT. The reduced time and ease of scheduling for the family in gshFBT will allow for an increased reach of treatment to a greater proportion of families in need.

  PublisherOA PDFDOI

Recent grants

• UCSD Integrated Cardiovascular Epidemiology Fellowship

  NIH · $5.6M · 2007–2027

• Promoting Physical Activity in Latinas via Interactive Web-based Technology

  NIH · $7.0M · 2017–2025

• NIH Grant R01HL069866

  NIH · $1.9M · 2008

• NIH Grant R01CA077249

  NIH · $1.7M · 2004

• NIH Grant R01NR011295

  NIH · $4.7M · 2020

Frequent coauthors

• Shira Dunsiger

  John Brown University

  325 shared

• Beth C. Bock

  Brown University

  192 shared

• Beth A. Lewis

  University of Minnesota

  154 shared

• Melissa A. Napolitano

  Milken Institute

  149 shared

• John M. Jakicic

  142 shared

• Anna E. Albrecht

  École Polytechnique Fédérale de Lausanne

  135 shared

• Jessica A. Whiteley

  University of Massachusetts Boston

  133 shared

• Britta Larsen

  University of California, San Diego

  123 shared

Education

• Ph.D.

  Brown University

• M.S.

  University of California, Los Angeles

• B.A.

  University of California, Los Angeles

Awards & honors

• President’s Lecture, 2015
• American College of Sports Medicine Citation Award, 2015
• Editor’s Choice Award for Best Paper of the Year, American J…
• UC San Diego Equal Opportunity/Affirmative Action and Divers…
• “Women Who Mean Business” Award, San Diego Business Journal,…