(Bloomberg) — In the fitness center at an investment management firm, Chris Serrano swipes cold goo across my stomach and waves an ultrasound wand. He’s about to perform a test “very similar to what they would do if you were pregnant,” he explains, only this one will measure, to the nearest tenth of a percentage point, just how much of my body is fat.

Already he’s grilled me on my health: How many glasses of water do I drink each day? (Not enough.) Can I name three foods with omega-3 fatty acids? (Apparently not; I thought broccoli had all the nutrients.) Next, he’ll have me do lunges, squats, leg lifts and side planks that will reveal, unsurprisingly, that my core and hips are weak. (His prescription: Work out more.) 

Serrano, a former college football player-turned-fitness trainer, is one of the key perks of working at FS Investments. He’s also one of the very first people new recruits meet when they start. Their meetings with him, at which they, too, will get their bodies and exercise analyzed, are just phase one in the company’s elaborate, all-encompassing employee-wellness program.

Related: Wellness programs on the rise as employers consider more than ROI

That program, dubbed “the Journey,” was custom-made for FS by Exos, a pro-athlete training center turned corporate-wellness business. At other companies, such as Google or Intel Corp., Exos might outfit a fitness center or offer nutrition consultations. But at FS Investments, whose program goes far beyond any others Exos offers, the perks—free meals, gym, workout classes, personal trainers, nutritionists—permeate even the most mundane details of nearly all its employees’ everyday lives.

The corporate-wellness business — from once-a-year biometric screenings to all-encompassing programs such as the one FS offers — has ballooned to a $6.8 billion industry, according to IBISWorld analyst Kelsey Oliver, all on the promise of reducing employers’ health insurance costs. Employers pour money into such initiatives — not that they have much to show for it. Multiple studies (PDF) by the RAND Corp. have found that such programs don’t save companies as much money on health care as they cost — even when lots of employees participate, which they generally don’t do. After all, the medical events, like heart attacks, that cost employers so much aren’t so easily prevented. “The link between your behavior and the costly events is way too weak to ever make a business case,” Soeren Mattke, an author of the RAND studies, says in an interview. “It is extremely hard to reduce costs by changing behaviors.”

Despite such evidence, many employers still believe in the power of wellness programs and are trying to get more employees on board. Many turn to such incentives as prizes or gift cards. Others threaten fees for not participating. FS Investments, however, doesn’t really give employees a choice. Sure, the moderately invasive consult with Serrano is technically optional, but it’s required for employees to get on the meal plan — and who’s going to turn down endless free food?

As a result, FS Investments’s has unheard-of participation rates. Almost everybody eats the free meals (those I speak with rave about them), and around three-quarters of the Philadelphia-based company’s 330-odd employees participate in the on-site fitness programs, which range from yoga to weight-training to a walking club. The gym, open 24/7, offers morning, evening, and mid-day classes; sometimes whole teams leave their desks to go work out together. Around two dozen people are in the 7:30 a.m. weight-training class I attend.

The cafeteria offers healthy options for breakfast, lunch, and — for employees who work late — dinner. Each meal is portioned out by “zones” determined by Serrano and staff dietician Becki Rabena; people in Zone 1 get the fewest calories, those in Zone 5 the most. (Everyone gets a cup and a half of vegetables.) The cafeteria is somewhat covert about portions; nobody has to know anybody else’s zone. 

Rabena explains all of this to new hires during a Nutrition 101 session. Like Serrano, she’s someone new hires meet early on, and her consultation, like his, kicks off with a series of questions — medical history, health goals, eating habits — before diving into the program’s theory. Her meal plan’s mantra is what it calls the 80/20 rule: Eat “clean” 80 percent of the time, “and then 20 percent of the time realize that we are all human,” she says. “Parties happen.” All food served in the office meets the “clean” requirement.

For lunch, I have sesame-ginger salmon over wild rice, with a pile of roasted vegetables dumped on top. It’s delicious and filling, and I realize that for free meals like this every day, I’d happily submit to some health assessments, too. 

Michael Forman, the firm’s chief executive officer, won’t say how much he pays for the program, except that the cost is “not insignificant.” (Exos won’t say, either, explaining that it doesn’t have a “set price” for its wellness offerings.)  But Forman says his company’s health insurance costs are down 23 percent year-over-year and that its participating employees collectively reduced their body fat by 10 percent in the program’s first year. One employee, Zach Cain, tells me he lost over 45 pounds in a year and a half.  

Mattke, the researcher at RAND, says a program like FS Investments’ “will never, ever” have a return on its investment. RAND’s studies have found that while such programs can significantly reduce absenteeism, the savings to employers aren’t enough to make them pay off financially.

But Forman argues that his program has significant benefits beyond insurance savings: keeping workers at “peak performance” and helping to attract and retain talent. “If people have the outlet of exercise and people eat healthy, they're going to feel better about themselves,” he says. “They're going to contribute better at home and at work.” 

Still, for employees, all that healthy living can take some getting used to. There’s no soda or candy, although FS says it goes through 125 gallons of infused water a day. The cafeteria doesn’t do dessert, besides dark chocolate squares and the occasional sorbet. Employees joke about smuggling in “contraband” and “Exos-approved” treats for birthdays. “Those first few months were pretty tough. I went through carb withdrawal,” says Linda Dietch, who started her marketing job at FS a year and a half ago. “It feels like I want sugar all the time, and I can't have it. These little squares of chocolate are the only treat that I have to look forward to.” 

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