Here’s What Really Happens When You Go Meatless Just One Day a Week

A growing body of research confirms that abstaining from meat just one day a week has measurable benefits—for the body, the planet, and even institutional systems like hospitals and schools.

That simple shift is the core of Meatless Monday, the global public health campaign started in 2003 by advertising legend Sid Lerner in partnership with the Johns Hopkins Center for a Livable Future.

A new digital hub for Meatless Monday

Now in its 22nd year, Meatless Monday is entering a new era with the launch of a robust digital resource center created by the Center for a Livable Future, aimed at supporting public health professionals, institutions, and advocates. The upgraded platform collects two decades’ worth of research, multimedia content, and practical toolkits that can be adapted across workplaces, universities, local governments, and more.

“High meat diets have been linked to an array of serious public and planetary health threats,” said Shawn McKenzie, Director of the Johns Hopkins Center for a Livable Future. “The new Resource Center will help ensure that the best Meatless Monday materials, tools, and resources continue to be available to everyone who cares about public health, our planet and food systems change.”

The environmental case for eating less meat

McKenzie’s warning about the dangers of meat-heavy diets isn’t abstract. A study published in Nature Food in 2023 found that food systems are responsible for roughly one-third of global greenhouse gas emissions, and the majority of those emissions stem from animal agriculture. Producing beef alone is more carbon-intensive than nearly all other protein sources combined, generating approximately 60 kilograms of carbon dioxide per kilogram of meat.

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By comparison, emissions from legumes, vegetables, and grains are significantly lower. A single day without meat each week can reduce an individual’s annual carbon footprint by as much as 186 kilograms, according to a study by the University of Oxford. Scaled globally, that shift could significantly curb the food sector’s climate impact.

A weekly reset for lifelong health

Meatless Monday has long emphasized this environmental benefit of omitting meat once a week, but the health implications are equally powerful. A 2021 study from Harvard T.H. Chan School of Public Health found that substituting plant-based proteins for red meat can reduce the risk of cardiovascular disease by up to 14 percent. Even moderate reductions in red and processed meat have been linked to lower rates of cancer, obesity, and type 2 diabetes.

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“Sid’s original vision was to create initiatives that anyone could pick up and shape for their own institutions and lives, or as Sid said, ‘take my campaign please,’” said Dana Smith, Campaign Director for The Monday Campaigns. “[22] years later, institutional partners and advocates worldwide have embraced Monday as, also in Sid’s words, ‘the day all health breaks loose.’ We’re excited for the next chapter of this movement, anchored to trusted and leading academic partners.”

Syracuse University expands the Healthy Monday movement

One of those anchor institutions is the Lerner Center for Public Health Promotion and Population Health at Syracuse University’s Maxwell School. The center is now overseeing Healthy Monday, a complementary program that encourages weekly wellness resets focused on habits like stress management, physical activity, and nutrition. Originally launched in 2006 as an expansion of the Meatless Monday campaign, Healthy Monday will now house its own slate of downloadable programs and outreach materials, aimed at building healthy routines through regular Monday check-ins.

“Healthy Monday is a dynamic, adaptable campaign that helps people start their week off right,” said Casey Collins, Digital Specialist for the Lerner Center. “As everyone from students to health professionals look for ways to achieve better health and wellbeing for themselves and the population as a whole, Healthy Monday has tremendous potential. We’re excited to move this important public health initiative forward.”

Hospitals join the Monday Wellness effort

That adaptability is now extending into hospital systems. NYU Langone Health recently announced it will lead Healthy Monday for Hospitals, a new initiative tailored to healthcare professionals, patients, and their families. The program draws from the success of earlier pilot programs at institutions such as Columbia University Irving Medical Center, which introduced stress relief and mindfulness programming into its weekly schedule for medical residents and staff.

“Hospitals and healthcare systems are unique social and physical environments for health, with enormous potential to encourage healthy, sustainable actions from healthcare workers, patients and their families alike,” said Shari Esquenazi-Karonika, Senior Program Director of the Healthy Mondays for Hospitals program at NYU Langone Health. “Healthy Monday for Hospitals is an exciting effort to ensure good health—and the ‘Monday refresh’ radiates out from the hospital community as a step towards making wellness and self-care accessible to all.”

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Though Meatless Monday may sound like a small gesture, its strength lies in consistency and community-wide implementation. Across the US and beyond, entire school districts have adopted the program to improve child nutrition and reduce environmental waste. The Los Angeles Unified School District, for example, began offering Meatless Monday meals in 2012. According to a case study published by the Center for a Livable Future, that change not only cut food costs but also led to a significant increase in student interest in plant-based options.

Corporate dining programs and universities have followed suit. Colleges such as Columbia University, Johns Hopkins, and UC Santa Barbara have introduced Meatless Monday menus across campus dining halls, tying the movement to broader student-led climate goals. Some programs have even embedded meat-free Mondays into sustainability coursework and community challenges.

One day, big impact

The timing is no coincidence. Data collected by The Monday Campaigns shows that people are more likely to set intentions and adopt new habits at the start of the week. That psychological “fresh start effect” makes Monday an ideal day to shift eating patterns in a way that feels achievable and non-restrictive.

Research conducted by the Johns Hopkins Bloomberg School of Public Health and published in the American Journal of Preventive Medicine supports this strategy. Participants in the study who set health goals on Mondays were more successful in maintaining those behaviors over time, compared to those who began on other days.

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In practical terms, Meatless Monday does not require participants to become vegetarian or vegan. Instead, it presents a low-barrier entry point into the benefits of plant-based eating. Campaign organizers offer meal ideas, budget-friendly recipes, and institutional playbooks that make it easier to adopt plant-forward habits without drastic lifestyle changes.

For many, it is the simplicity of the idea—combined with its documented impact—that makes Meatless Monday enduring.