New: our analysis tool now includes San Mateo County data
A data-driven analysis of obesity disparities across 370 census tracts reveals a stark east-west divide, and a roadmap for closing it.
Obesity affects up to 34% of residents in Santa Clara County's highest-burden neighborhoods - driving diabetes, cardiovascular disease, and depression, while compounding barriers to education and employment in communities already under structural stress.
Source: CDC PLACES (2025); U.S. Census Bureau, ACS (2019–2023); Random Forest Model (Test R² = 0.96)
New: Our tool now includes San Mateo County data →Using CDC PLACES 2025 data and machine learning across 370 census tracts, this research identifies the strongest predictors of obesity at the neighborhood level, and where the greatest need for intervention lies.
Depression, smoking, and housing insecurity predict obesity better than race, income, or education, even when both sets of factors are given to the model together. Mental health is an obesity intervention, not a separate concern.
SHAP Analysis · Random ForestAn east/west fault line runs through the county, with roughly a 5× gap in composite risk scores between the highest and lowest burden areas, where structural disadvantage compounds the cycle of chronic stress and poor health outcomes.
Composite Risk Score · 370 TractsTracts with the highest obesity have the lowest checkup and cholesterol screening rates. The communities that need preventive care most are getting it least, a critical equity finding with direct policy implications.
Care Gap · Equity FindingA note on the model: The Random Forest model behind these findings (Test R² = 0.96) was built by comparing health-only, demographics-only, and combined predictor sets, which is how we know behavioral health factors outperform demographics even when both are available to the model. Because the underlying CDC PLACES estimates are themselves modeled, not directly measured, figures, we treat tract scores as a tool for prioritizing outreach, not a diagnosis of any individual neighborhood.
Alongside community partners such as the Ecumenical Hunger Program, Sacred Heart Community Service Youth Action Group, and Asian Americans for Community Involvement (AACI), we provide grassroots awareness and education programs in three areas where the research shows the greatest need.
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We hold youth mental health workshops with schools and community partners to raise awareness and reduce stigma, providing children with hands-on tools to build everyday skills that support mental wellbeing. We also provide adult mental health resource guides, connecting community members to local counseling services, support groups, and crisis resources.
Food access and food literacy are distinct challenges. We partner with local organizations to deliver practical nutrition education in high-burden neighborhoods - equipping families with knowledge that makes a difference within the food environments they already live in.
Physical inactivity is one of the strongest co-predictors of obesity in our highest-burden tracts. We support community campaigns that promote accessible, low-barrier movement - recognizing that safe outdoor spaces and motivation are not equally distributed across neighborhoods.
Beyond these three focus areas, we design custom interventions matched to each neighborhood's specific risk profile. In Alum Rock, for example, a high-burden area spanning 3 census tracts with a composite risk score of 63.2/100, our recommended focus combines culturally-competent Medi-Cal enrollment through community health workers and bilingual access to county social services, alongside peer navigation to address depression (19.3% prevalence), the leading driver of risk there.
Sample focus areas: Mental health · Preventive care · Housing stability · Smoking cessation
3 census tracts · sample project
Estimated unmet need vs. availability
Whether you're a community organization, a policymaker, or a journalist, get in touch and let's talk about what's useful to you.
Get in touch →Henri Smit is a community service leader and AI & data science practitioner with a deep passion for healthcare, public health, and the power of data to drive meaningful change in underserved communities.
Healthy Santa Clara grew out of Henri's role on the Youth Action Committee at Sacred Heart Community Service in 2024, and his belief that data literacy is one of the most powerful tools available to the next generation of community advocates.
Whether you're a community organization, a policymaker, a researcher, or simply someone who cares about health equity in Santa Clara County, I'd love to hear from you.
Journalists: reach me directly at hsmit@healthysantaclara.com.