David Yeung believes that meat is the new tobacco. But the longtime vegetarian and practicing Buddhist won't try to get you to stop eating meat. He just wants you to consider eating less of it.

That's what he's trying to do with the citizens of Hong Kong, who collectively have the highest per-capita meat and seafood consumption in the world, according to a 2015 study by Euromonitor. (Surprising, right? We'll give you a moment to digest.) His life's mission is to get the citizens of our planet — particularly his home city — to cut out eating animals at least one day a week. And it's working: Menus inspired by his "Green Monday" philosophy appear in hundreds of restaurants across Hong Kong, and at schools and universities around the world.

Though Yeung grew up in Hong Kong, he spent over a decade living in New York. When he was 16, his family moved to nearby New Jersey to be closer to the fashion industry. His father was one of the four founders of the global clothing company Tommy Bahama. Yeung graduated from Columbia University in 1998 with a degree in engineering, spent a few years consulting for PwC and then launched a software startup (now defunct). He grew up eating meat, but in 2001 he dove into Buddhist philosophy, a core tenet of which is the truth of suffering. It wasn't a big leap for Yeung to go from looking inward to looking outward, and he quickly concluded that by changing his diet he could stop participating in the suffering of animals.