Where most weight-loss schemes try to keep up with the number of calories going into your body, this device produces data far more encouraging to dieters: a precise tally of calories that go out -- per day and per minute, neat as a balance sheet. To medical researchers, such numbers are pure magic, something no one has produced before with such precision on a portable device.

Just as impressive is the magic it took to turn the invention into a product -- and the product into a viable company. The magician is 32-year-old Astro Teller, CEO of Pittsburgh-based BodyMedia. Just 12 months ago, the startup had run out of money, had fired 40 percent of its staff, and was begging for investors to keep it alive. That chore fell to Teller, a guy lacking the kind of street cred you need on Sand Hill Road these days if you want a big check.

The Company

BodyMedia

HQ Pittsburgh

Employees 20

Revenue $700,000 (2002 est.)

Major customers Roche Diagnostics, ClubCom

Venture funding $17 million, from Draper Fisher Jurvetson, University of Pittsburgh Medical Center, and others

But he tried anyway. An artificial-intelligence Ph.D. who had written a successful sci-fi novel (he's also the grandson of Edward Teller, inventor of the hydrogen bomb), Teller believed that the monitor could be the centerpiece of an online "health portal" that would track a person's daily statistics on sleep and exercise. Right. "We had no credibility," recalls Jeff Swoveland, BodyMedia's chief financial officer. "We kissed every frog. Nobody wanted to hear the pitch."

Yet with dogged persistence, Teller managed to invent a company to go along with the invention. DFJ ePlanet Ventures, a portfolio company of Draper Fisher Jurvetson, led BodyMedia's $6.5 million second round last summer, and today Teller's quixotic notions are actually cracking a new market in the booming weight-loss industry.

Roche Diagnostics, a $5 billion maker of medical testing equipment -- which sells diabetes self-exams through CVS (CVS) and Wal-Mart (WMT) -- recently agreed to develop BodyMedia's sensors as exercise-trackers for patients on weight-loss and cardiac programs. Another dozen partners and testers (including the Pittsburgh Steelers, who see the armband as a new way to monitor athletic conditioning) have signed up with Teller.

How Astro Won Over the VCs

Be persistent."It's not about delivering balloon animals to a VC's office. It's about making a lot of phone calls."

The tech is 5 percent of the pitch. "People don't invest in a physical product, but in the team and the trends."

Don't talk the talk. "So many people get wound up about the pitch -- ‘I'll somehow con you into getting your money.' That's not a partnership that will turn out well."

Show integrity. "When you go to the edge of the abyss, fix a problem, live up to every obligation, you start getting credibility."

Variety is good. "You try to raise money from a number of different investors. That way you get all of their help."