Introduction to the Study
America's Mental Health Emergency
The United States is facing a significant and worsening mental health crisis. According to a KFF/CNN study (July–August 2022), 90% of U.S. adults believe the country is grappling with a mental health emergency. The COVID-19 pandemic upended daily life, leading to prolonged isolation, education disruptions, and increased stress levels, particularly among young people. In the United States, one in four adults, 58.7 million people, live with a mental health condition.
The impact on youth mental health has been severe. Rates of depression and anxiety among adolescents rose significantly from pre-pandemic levels. Between the first and second year of the pandemic, there was a 6.7% increase in youth with any mental health emergency department (ED) visits. Among adolescent females, this increase was even higher at 22.1%. According to an Olivery Wyman study conducted in 2023, nearly two-thirds (65%) of Gen Z reported experiencing at least one mental health problem in the past two years.
Beyond the pandemic's direct effects, climate anxiety is also contributing to rising stress levels. According to the Deloitte survey "2024 Gen Z and Millennial Survey: Living and working with purpose in a transforming world," 6 in 10 Gen Z reported feeling anxious about the environment, with extreme events and wildfires as major stressors.
The pandemic also blurred the lines between personal and professional lives, contributing to increased stress and burnout. According to the APA's 2021 Work and Well-being Survey, 79% of U.S. employees reported work-related stress, with 44% experiencing physical fatigue—a 38% increase since 2019.
Mental illness has a significant economic impact, costing the U.S. an estimated $282 billion annually, according to a paper published in The National Bureau of Economic Research in 2024. This staggering cost reflects the ways that mental illness can stymie investment, productivity, and wealth accumulation, highlighting the urgent need for effective mental health policies.
As mental health challenges persist, the United States also faces an unsustainable healthcare crisis, driven largely by chronic diseases linked to poor nutrition and lifestyle choices.
The Chronic Disease Crisis
Chronic diseases account for 90% of U.S. healthcare spending. According to the CDC, six in ten Americans have at least one chronic disease, and four in ten have two or more. These chronic diseases include obesity, type 2 diabetes, heart disease, stroke, and certain cancers - all of which can be impacted by poor nutrition and physical inactivity. The impact of these conditions is not only a health crisis but also a major economic burden.
The COVID-19 pandemic has further complicated the issue of chronic disease, both by introducing new chronic conditions and exacerbating existing ones. During this period, obesity rates increased significantly, with prevalence rising from 11% to 25.3% in men and from 15% to 42.4% in women. This sharp increase suggests a strong correlation between the pandemic and rising obesity levels.
Research indicates that COVID-19 is associated with long-term health effects, including an increased risk of heart complications and other chronic conditions. Many individuals, even those with mild cases, have experienced lingering symptoms such as fatigue, brain fog, respiratory issues, and cardiovascular concerns.
This phenomenon, commonly referred to as "long COVID" or "post-COVID-19 syndrome," can significantly impair an individual's mental and physical quality of life, placing an additional strain on healthcare systems. The pandemic heightened public awareness regarding the importance of a healthy diet and lifestyle in supporting immune systems and overall well-being.
Cost-effective preventive solutions like diet remain underutilized. As healthcare costs continue to rise and mental health worsens, there is an urgent need to explore preventive lifestyle changes. While food access remains a challenge for many, the choices we make at each meal—up to three times a day—can be a powerful tool for prevention. A Whole Food Plant-Based (WFPB) diet, shows promise in boosting both mental and physical well-being.
The Health Benefits of Plant-Based Nutrition
The link between plant-based diets and physical health is well-established. For example, the EPIC-Oxford study found that vegetarians had a 23% lower risk of ischemic heart disease and a 35% lower risk of diabetes compared to meat-eaters. A Harvard study on the Planetary Health Diet Index (PHDI) found that people with higher adherence to plant-based diets experienced 23% lower risk of total mortality, 14% lower risk of cardiovascular mortality, and 10% lower risk of cancer mortality.
A healthy, plant-based diet aims to maximize the consumption of nutrient-dense plant foods while minimizing processed foods, oils, and animal foods, encouraging the consumption of vegetables, fruits, beans, peas, lentils, soybeans, seeds, and nuts. Plant-based diets typically have high intakes of carbohydrates, n-6 fatty acids, dietary fiber, carotenoids, folate, vitamin C, vitamin E, and magnesium.
A study published in the Permanente Journal, "Nutritional Update for Physicians: Plant-Based Diets" recommended whole foods plant based diets as cost-effective, low-risk interventions that may lower body mass index, blood pressure, and cholesterol levels, as well as reduce the amount of medications needed to treat chronic diseases.
"Physicians should consider recommending a plant-based diet to all their patients, especially those with high blood pressure, diabetes, cardiovascular disease, or obesity," the report's abstract said.
Income Disparities Impact on Nutrition and Health
Many Americans live in food deserts, where access to healthy foods at grocery stores is limited. The U.S. Department of Agriculture (USDA) defines food deserts as areas where people live more than 1 mile from a supermarket in urban areas, or ten miles away in rural areas. Food deserts are also commonly referred to as "any place where fresh food is sparsely available" People may not live near farmers markets, where they can buy unprocessed foods, including fruits and vegetables. According to the USDA, 19 million Americans, or 6% of the population, resided in a food desert.
Food insecurity disproportionately affects specific populations. Researchers from Northwestern University studied U.S. Census Household Pulse Survey(HPS) Data collected between April 23 - May 19, 2020. The data showed that 23% of all households experienced food insecurity. However, racial and ethnic disparities are evident, with 36% of Black households and 32% of Hispanic households facing food insecurity, compared to 18% of White households. In 2022, over 44 million Americans faced food insecurity.
Healthy foods tend to cost more, limiting access for people with lower incomes. Americans with underlying comorbidities struggle to afford healthy foods. People from lower economic situations may not have the resources to make dietary choices. Americans making under $50K are more likely to shop for groceries at Big Box Stores, like Walmart and Target.
COVID-19 impacted Americans' everyday lives and their ability to access nutritious foods. The pandemic disrupted food shopping patterns and exacerbated existing problems with food deserts and transportation access. COVID-19 restrictions impacted transportation options and workplaces, limiting access to larger supermarkets for underserved low-income neighborhoods.
People with lower incomes experience chronic illness at higher rates, including COVID-19, as highlighted in the GAIA study. Food insecurity and nutritional deficiencies contribute to weakened immunity defenses and physical health decline.
A study published in the American Journal of Preventative Medicine in 2022 found that food insufficiency increased during the COVID-19 pandemic and affected vulnerable populations, placing "individuals at higher risk for symptoms of poor mental health." This study found that the rate of food insufficiency in the U.S. increased from 8.1% to 10.0% between March and June 2020, during the COVID-19 pandemic and recommended physicians should screen their patients for food insufficiency and mental health outcomes, as the researchers observed a connection.
The GAIA Study and Lifestyle Medicine
The GAIA study expands our knowledge of the intersections between health and diet, by uncovering how what we choose to eat impacts our mental health and outlook on life.
The GAIA study provides evidence that people who consume plant-based diets report higher stress resilience, greater emotional stability, and fewer symptoms of anxiety and fatigue compared to those consuming SAD. The GAIA study also revealed that people who consumed a WFPB diet reported fewer comorbidities like obesity, hypertension, and diabetes, which are major cost drivers in healthcare.
The findings from the GAIA study align with broader research on plant-based nutrition and mental health. A review published in 2021 for Current Nutrition Reports examined how plant-based diets may support long-COVID recovery and overall mental resilience. The study found that individuals following a plant-based diet experienced a 73% lower likelihood of moderate-to-severe COVID-19 symptoms.
In addition to better COVID-19 outcomes, the study highlighted potential improvements in common long-COVID symptoms, such as fatigue, sleep disorders, headaches, anxiety, depression, and musculoskeletal pain. The study underscored the potential role of tryptophan—a key amino acid found abundantly in plant-based foods—in supporting mental health, as it is essential for serotonin production and mood regulation.
Lifestyle Medicine and Mental Resilience
Lifestyle Medicine, one of the fastest growing board specialties in the United States, prioritizes nutrition and physical activity as recommendations to improve health.
The American College of Lifestyle Medicine (ACLM) is pioneering research and clinical applications of plant-based nutrition as a key intervention for chronic disease management. ACLM spearheads new studies and treatment approaches, including the use of plant-based nutrition to support Type 2 Diabetes remission.
The American College of Lifestyle Medicine identifies six pillars of health which include a holistic approach to health and a focus on plant-predominant eating patterns. The pillars include nutrition, physical activity, stress management, restorative sleep, social connection, and avoidance of risky substances. The GAIA study surveyed responses across all six pillars, in the context of a global health crisis.
Nutrition
Physical Activity
Social Connection
Avoid Risky Substances
According to an ACLM study, health care providers practicing Lifestyle Medicine (LM) had 43% lower incidence of mental burnout than those who did not.
The GAIA study builds on these principles, demonstrating how a plant-predominant diet not only supports physical health but also enhances mental resilience, reinforcing the critical role of nutrition in overall well-being.
What the GAIA study uniquely demonstrates is the direct link between our mental health and resilience and plant-based diets.
Food is not just fuel for our bodies but also nourishment for our minds, and plant-based foods provide the nutrients necessary for positive mental well-being.
"It is the first of its kind initiative to take such a close look at a fast-growing part of the US population, namely those who follow a plant-based diet" said Dr. Verena Rossa-Roccor, MD, MSc, PhD (University of British Columbia), a psychiatrist, epidemiologist and scientific advisor for the study. "We have learned that they come from every walk of life, that they have very different, individual dietary patterns, and that there are complexities to what we eat, why we eat it, and what impact it has on our lives beyond what is typically considered in studies on nutrition and health."
Learn More About the GAIA Study Findings
Explore how different dietary patterns affect physical and mental health outcomes during global health crises.