Over the last decade, phrases like “go green” and “reduce your carbon footprint” have become firmly embedded in our vocabulary, just as Earth Day has become an annual celebration.

As an environmental advocate, this couldn’t make me happier. I’ve been inspired to see people switching to efficient light bulbs, and beginning to use canvas shopping bags instead of paper or plastic. Nearly two thirds of Americans say they recycle on a regular basis compared to a quarter of Americans in the 1990s. Though more people have come to recognize the carbon footprint cost of everyday behaviors like driving cars, a leading cause of environmental degradation has remained largely hidden: factory farming.

According to the United Nations, animal agribusiness plays a prominent role in climate change. Wherever factory farms operate, there is sure to be environmental degradation. Untreated manure from hog farms runs off into waterways, killing fish and causing algal blooms. When this waste inevitably reaches our oceans, it creates what scientists call dead zones, areas of the ocean where all life dies off or moves away due to a lack of oxygen.

The damage animal agribusiness has done to our planet is well-documented and ever-increasing. As our population grows, so does our demand for meat.

The good news is, more and more people are realizing how what they put on their plates impacts our planet. As a result, we as a nation are enjoying more meat-free meals as a way to help ourselves and the planet that sustains us.

Since its inception in 2003, Meatless Monday has mushroomed. The idea is simple: enjoy a holiday from meat one day a week. It’s a simple solution with manifold benefits. According to the Environmental Defense Fund, “If every American skipped one meal of chicken per week and substituted vegetables and grains … the carbon dioxide savings would be the same as taking more than half a million cars off of U.S. roads.” A Carnegie Mellon University study found that we would each do more good for the planet if we skipped meat just one day a week than if we ate exclusively local foods.

Of course, eating fewer animal-based foods and more plant-based foods is good for our health, too. The American Heart Association recommends “substituting some of the meat in your diet with vegetables” as a simple way to reduce our risk of heart disease — America’s number one killer. Even former governor of California Arnold Schwarzenegger has touted the virtues of meatless eating, pointing to fitness celebrity and vegetarian Bill Pearl, who according to Schwarzenegger is, “… one of the greatest bodybuilders ever.”

Equally exciting is the new world of food you’ll begin to explore when you enjoy more meatless meals. From Indian and Ethiopian dishes, to familiar favorites like spaghetti with marinara and vegetables or bean burritos, there’s no shortage of options.

Perhaps the easiest and tastiest way to improve our diet is by practicing the Three Rs: reducing or replacing consumption of animal products, and refining our diets by choosing products from sources that use higher animal welfare standards.

If millions of people make these small changes, it makes a big difference. Each of us, by pledging this Earth Day to participate in Meatless Monday, can make a tremendous difference for the world and its inhabitants all year long.

Kristie Middleton is senior food policy director for The Humane Society of the United States.