According to a recent report by the McKinsey Global Institute, nearly 30 percent of the world’s population is overweight or obese. That’s almost two and a half times the number of humans worldwide who are undernourished. And, say the report’s authors, unless we do something soon to change the current trajectory, almost half of the world’s adults will be overweight or obese by 2030. All those extra pounds add up to a big problem: Obesity’s global economic impact is a staggering $2 trillion—yes, trillion with a “t”—per year.

While this is a complex issue that needs to be addressed on many fronts, there’s one simple thing that all of us can do right now—and encourage our loved ones to do as well—that will help reverse the trend: Eat vegan.

After comparing five common diets, researchers at the University of South Carolina concluded that eating a vegan diet is the most effective way to lose weight. The researchers placed overweight volunteer dieters into five groups—omnivores, semi-vegetarians, pesco-vegetarians, vegetarians, and vegans—and provided participants with healthy recipes, diet information, and access to support groups. By the end of the six-month study, participants in the vegan group had lost an average of 16.5 pounds each—more than those in any other group.

Previous research has shown that vegans generally have lower body mass indexes than either vegetarians or meat-eaters and that the average vegan is 18 percent leaner than his or her meat-eating counterpart.

It’s no wonder that health insurance companies in the United Kingdom and the Netherlands offer discounted rates for vegans, and The Permanente Journal, a peer-reviewed journal put out by U.S. health giant Kaiser Permanente, stated, “Healthy eating may be best achieved with a plant-based diet.”

Eating vegan can save consumers (and our overburdened health-care system) money in the long term by reducing people’s risk of developing obesity, heart disease, high blood pressure, cancer, and other costly health conditions that consumers of meat and dairy products are more prone to. But did you know that vegans can also save money right now—on their food bills? There’s nothing more budget-friendly than a bag of dried beans. Pasta, lentils, brown rice, oatmeal, and peanut butter are some other inexpensive vegan foods that you probably already have in your pantry.

So why not give vegan eating a try? You’ll save money, your health, and—of course—animals! For tips on whipping up tasty and inexpensive vegan meals, check out Eat Vegan on $4 a Day by PETA’s 2014 Sexiest Vegan Over 50 contest winner Ellen Jaffe Jones.