Stacie Smeal, a fitness instructor in New York, says that she doesn't need health care and that the idea of a government mandate "disgusts" her. Al Jazeera America

NEW YORK — Stacie Smeal’s entire life is about living healthy. She eats only organic food; she works out daily for hours at a time. The fitness entrepreneur has even launched a website encouraging people to follow her habits. Yet one thing lacking from her life is medical insurance.

“In general, I don’t need health care,” Smeal, 27, said. “I exercise and eat healthy, so I’m generally a healthy person.”

She lives on her own in New York and doesn’t have a full-time job. She said she simply can’t afford medical insurance. Yet as the launch of the Affordable Care Act (ACA) nears, she is among millions of Americans who will soon forced to buy insurance.

“It disgusts me,” Smeal said of the health care law. She said she feels as if she’s being punished for striking out on her own and worries the new requirements will push her to full-time work just so she can afford insurance.

“I just can’t comprehend working 35 hours a week, where I’m bringing in, after taxes, $200, $250 a week, just so I can have health insurance that I might use once that year,” she said. “Who wants to work just for your health insurance?”

Yet it’s young people like Smeal that Barack Obama's administration has said are most needed to make health care reform a success. The new insurance exchanges, which open Tuesday, hope to attract at least 2.7 million of the 17 million uninsured 18-to-34-year-old Americans. That age group is dubbed the young invincibles and is the demographic least likely to be insured. Enrolling young adults, who often pay for but rarely use health insurance, is needed to keep premiums low overall.

“If they don’t get a lot of young people to sign up, this bill becomes much more expensive than the president thought it would be,” said Basil Smikle, a political consultant and an adjunct professor at Columbia University. “The president is counting on the fact that there are a number of young people that can spread out the risk and allow some of the sicker, older folks to be able to benefit.”