Youth-Led Public Health Research · Santa Clara County

In one of America's wealthiest counties, where you live determines how healthy you are.

A data-driven analysis of obesity disparities across 370 census tracts reveals a stark east-west divide — and a roadmap for closing it.

Higher obesity risk in East San Jose vs. Cupertino
370
Census tracts analyzed across Santa Clara County
14–34%
Range of obesity prevalence across the county
#1
Depression as the strongest predictor of obesity risk

Source: CDC PLACES 2025 · ACS 2019–2023 · Random Forest Model (Test R² = 0.96)

DepressionTop Predictor East San JoseCritical Risk Alum RockAvg Score 63.2 Preventive CareInverted Housing Insecurity#3 Predictor GilroyAvg Score 56.9 5× Risk GapEast vs. West R² = 0.96Model Accuracy DepressionTop Predictor East San JoseCritical Risk Alum RockAvg Score 63.2 Preventive CareInverted Housing Insecurity#3 Predictor GilroyAvg Score 56.9 5× Risk GapEast vs. West R² = 0.96Model Accuracy
Key Findings

Three findings that demand action

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.

01

Behavioral health beats demographics as a predictor

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 Forest
02

The geography is sharply divided

An east/west fault line runs through the county. East San Jose, Alum Rock, Gilroy, and Morgan Hill carry the highest burden. Cupertino, Saratoga, and the Palo Alto corridor sit at the bottom — a roughly 5× gap in composite risk scores.

Composite Risk Score · 370 Tracts
03

Preventive care is inverted

Tracts 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 Finding
Priority Cities

Five cities with critical obesity risk tracts

The composite risk score — combining RF prediction, depression, smoking, housing insecurity, and care gaps — identifies where intervention resources are most urgently needed.

Alum Rock63.2 avgCritical
Gilroy56.9 avgCritical
Morgan Hill45.0 avgHigh
San Jose42.0 avg118 Tracts High/Critical
Stanford40.1 avgHigh
Obesity Risk Score by Census Tract Santa Clara County · CDC PLACES 2025 Composite Score: RF + Depression + Smoking + Housing + Care Gaps
Get Involved

This research is most powerful when it drives action

Whether you lead a community organization, shape public policy, or cover public health — there is a role for you in this work.

🤝

Community Organizations & Nonprofits

Use this data to strengthen your funding applications

The composite risk score and city-level findings give community organizations a defensible, data-driven tool to prioritize neighborhoods and justify resource allocation in grant applications and program design.

Request the data package →
🏛️

Government & Policymakers

Place-based interventions backed by tract-level evidence

The research supports targeted investment in mental health access, housing stability, and preventive care in the highest-burden tracts. A policy brief is available for city and county stakeholders.

Request the policy brief →
📰

Media & Press

A compelling story about equity in America's most affluent county

A high school researcher using machine learning to expose a 5× health gap between East and West San Jose — and connecting the dots to depression, housing, and preventive care access. A press kit is available on request.

Request the press kit →
HS
Henri Smit
Researcher · Crystal Springs Uplands School · Class of 2027
About the Researcher

Passionate about using data and AI to advance health equity in underserved communities

Henri Smit is a junior at Crystal Springs Uplands School in Hillsborough, CA, with a deep passion for healthcare, public health, and the power of data to drive meaningful change in underserved communities.

This research grew out of Henri's role on the Youth Action Committee at Sacred Heart Community Service and his belief that data literacy is one of the most powerful tools available to the next generation of community advocates.

AI Research Intern, Onclusive Inc., London — LangChain, RAG, and LLM evaluation pipeline
Emory Medical School HITI Lab — 3rd Place, Emory Health AI Datathon
Independent immunology research — manuscript under review, Journal of Emerging Investigators
Co-founder, Youth Action Committee (Public Health) — Sacred Heart Community Service
Founder, iedereen.org — youth media platform on healthcare access and affordability
Contact Henri →
Get In Touch

Ready to collaborate or learn more?

Whether you are a community organization, a policymaker, a journalist, or simply someone who cares about health equity in Santa Clara County — we would love to hear from you.