As obesity rates, health-care costs, and an emphasis on prevention all rise, so does the wellness realm: It’s set to be the next trillion-dollar industry, according to data from private market research firm Women’s Marketing Inc., in partnership with Rodale (the publisher of Women’s Health). So it’s no wonder that wellness coaching is one of the fastest-growing areas of the overall coaching industry. An estimated 20,000 coaches have sprung up since the field emerged 17 years ago, says Margaret Moore, CEO of training school Wellcoaches Corporation and codirector of the Institute of Coaching at McLean Hospital in Boston.And there’s the catch: Because the specialty is still relatively new, there’s no organization that ensures all wellness coaches get proper training and stick to standards—or requires them to have any qualifications. Anyone can hang out their shingle as a wellness coach—the mom who has read a few books about nutrition, the trainer at the gym, or your multilevel-marketing Facebook friend who’s constantly hawking supplements. Lots of people who bill themselves as wellness coaches have no idea what that really means. “The word wellness is pretty vague, so that might contribute to the problem—and there’s a risk that unqualified coaches could do more harm than good,” says Webster. Here’s how to hire the right person.