The latest research from the University of Washington's Institute for Health Metrics and Evaluation (IHME), published in the Journal of the American Medical Association (JAMA) on January 28, 2026, paints a sobering picture of the ongoing obesity epidemic in the United States. Titled "US State-Level Prevalence of Adult Obesity by Race and Ethnicity From 1990 to 2022 and Forecasts to 2035," the study projects that by 2035, nearly 47% of American adults—or 126 million people—will be living with obesity, up from 107 million in 2022. This represents an increase of 19 million individuals, underscoring the persistent upward trajectory despite public health efforts.
Obesity, defined as a body mass index (BMI) of 30 or higher—where BMI is calculated as an individual's weight in kilograms divided by the square of their height in meters—has more than doubled in prevalence since 1990, when it affected just 19.3% of adults, or about 34.7 million people. The researchers, led by Catherine O. Johnson, PhD, MPH, a lead research scientist at IHME, utilized sophisticated modeling techniques including spatiotemporal Gaussian process regression and Bayesian spline models to analyze data from over 11 million participants across major surveys like the National Health and Nutrition Examination Survey (NHANES), Behavioral Risk Factor Surveillance System (BRFSS), and Gallup Daily Survey.
Historical Trends: From 19% to Over 42% in Three Decades
Tracing the arc of the obesity epidemic reveals a steady climb driven by intertwined societal shifts. In 1990, obesity rates stood at 19.3%, reflecting a time when processed foods were gaining popularity but ultra-processed items had not yet dominated diets. By the early 2000s, rates accelerated, surpassing 30% amid expanding portion sizes, increased sedentary lifestyles fueled by desk jobs and screen time, and marketing of high-calorie beverages. The 2022 figure of 42.5% marks a more than doubling, with women consistently outpacing men—partly due to biological factors like hormonal influences and pregnancy-related weight retention, compounded by cultural pressures.
This progression wasn't uniform. The post-2010 plateau some hoped for proved illusory; rates resumed climbing, particularly among younger adults. For instance, women under 35 have seen the sharpest recent increases, signaling potential for earlier onset of comorbidities like type 2 diabetes and heart disease. Middle-aged adults (45-64) bear the highest burden currently, at rates exceeding 45% in many groups.Public health researchers at universities like the University of Washington have been pivotal in tracking these shifts through longitudinal data analysis.
National Projections: 126 Million Adults by 2035
The forecast to 46.9% prevalence by 2035 assumes continuation of recent trends, projecting 126 million affected adults (95% uncertainty interval: 118-134 million). This equates to nearly one in two Americans over 20, straining healthcare systems already burdened by obesity-related costs nearing $200 billion annually in 2019. Without intervention, severe obesity (BMI ≥40) will also rise, exacerbating risks for conditions like osteoarthritis, sleep apnea, and certain cancers.
Dr. Johnson notes, “Our projections indicate that almost half of US adults will be living with obesity by 2035,” highlighting the urgency. These models account for demographic changes like aging populations and immigration patterns but do not yet fully incorporate emerging factors like widespread GLP-1 receptor agonist use (e.g., semaglutide in Ozempic or Wegovy).
State-Level Variations: Midwest and South Lead the Crisis
Geographic disparities are stark, with Midwestern and Southern states topping prevalence charts. States like West Virginia, Mississippi, and Alabama consistently report rates above 45%, linked to rural food deserts—areas with limited access to fresh produce—and economies reliant on manufacturing with low physical activity demands. In contrast, Colorado and California project slower growth, buoyed by active lifestyles, bike-friendly infrastructure, and policies like soda taxes in Berkeley.
- Midwest: High due to agricultural diets high in processed carbs and harsh winters limiting outdoor activity.
- South: Cultural staples like fried foods, combined with poverty and heat-related inactivity.
- West: Better outcomes from wellness cultures and urban planning promoting walking.
California, for example, expects rates around 40-45% by 2035, lower than the national average, thanks to initiatives like school nutrition standards (SB 12, SB 677).
Racial and Ethnic Disparities: Widening Gaps Demand Equity
Race and ethnicity amplify risks, with 2022 age-standardized rates highest for non-Hispanic Black females at 56.9%, followed by Hispanic females and males. Non-Hispanic White males lag at 40.1%. By 2035, Black women could hit 59.5%, Latino women 53.7%. These gaps stem from systemic issues: food insecurity in minority neighborhoods, higher stress from discrimination (elevating cortisol and appetite), and barriers to healthcare. Within states, disparities are larger for women; e.g., in California, Latino/Black women near 60% vs. 40% for White women.
Dr. Amanda Velazquez of Cedars-Sinai emphasizes, “These numbers are not surprising, given the systemic inequalities.” University-led studies like this inform targeted interventions, such as community programs at community colleges in affected areas.
Photo by Luca Cavallin on Unsplash
Severe Obesity and Age-Specific Trends
Severe obesity, posing the gravest risks, mirrors overall patterns but with steeper climbs among youth transitioning to adulthood. Young women show explosive growth, potentially due to social media influences on eating disorders rebounding into overeating, plus post-pandemic habits. Middle age peaks from metabolic slowdowns unmitigated by lifestyle. Projections warn of a cohort effect: today's young obese entering prime working years with heightened disease burdens.Read the full JAMA study.
Root Causes: A Multifactorial Public Health Challenge
Obesity arises from gene-environment interactions. Key drivers include ultra-processed foods (60% of US calories, laden with sugars/fats engineered for addiction), sedentary behavior (average adult <5,000 steps/day), sleep deficits disrupting hormones like leptin/ghrelin, and endocrine disruptors in plastics. Socioeconomic layers: low-income groups face higher fast-food density, fewer gyms. The built environment—car-centric suburbs—exacerbates this. Dr. Johnson identifies “access to healthy food, aspects of the built environment, and physical inactivity” as core.
Health and Economic Impacts: A $1 Trillion Burden?
Obesity fuels 40% of diabetes, 20% of cancers, and halves life expectancy in severe cases. Healthcare costs: $173B in 2019, projected to double. Productivity losses from absenteeism and disability add hundreds of billions. Globally, World Obesity Federation estimates $4T GDP hit by 2035. In US, states like Mississippi face outsized strains on Medicaid.
Academic researchers in epidemiology and nutrition play key roles; explore higher ed research jobs tackling these issues.
Emerging Solutions: GLP-1 Drugs and Beyond
GLP-1 agonists like semaglutide offer 15-20% weight loss, potentially bending curves if scaled. However, high costs ($1,000+/month) and supply shortages limit access; only 6% eligible use them. Projections don't factor mass adoption, but Morgan Stanley sees $150B market by 2035. Complementary: policy (soda taxes reduced BMI 0.09 points in Berkeley), school programs, urban redesign. Clinicians urged to intervene early.
- Pharmacotherapy: GLP-1s for sustained loss.
- Lifestyle: Structured diets + exercise (e.g., Mediterranean).
- Policy: Subsidize produce, tax junk food.
- Education: University nutrition programs.
The Role of Academic Research in Combating Obesity
This JAMA study exemplifies higher education's impact: IHME at UW leverages big data for policy insights. Universities train epidemiologists, fund trials, and host centers like Harvard's Nutrition Source. Future breakthroughs may come from AI predictive models or gene therapies. Aspiring researchers can find opportunities via faculty positions or postdoc roles in public health.IHME study page.
Path Forward: Actionable Insights and Optimism
While daunting, reversibility exists—Japan maintains 4% obesity via cultural norms and policy. US needs multisector action: federal funding for prevention ($10B/year?), equitable drug access, workplace wellness. Individuals: track BMI, prioritize veggies/protein, 150min weekly exercise. Track progress at higher ed career advice resources. With concerted effort, we can defy projections. For jobs advancing this research, visit higher ed jobs, rate my professor, or university jobs.
CDC obesity data.