Preliminary figures suggest the Obama administration is falling far short of its goal of signing up the young, healthy and uninsured for ObamaCare.

It's a problem that could undermine the rollout of the law even more than the glitch-ridden website.

Experts say the health care program needs 40 percent of all enrollees to be between 18 and 34 years old -- a prized demographic known in the industry as the "young invincibles." They are considered young, healthy and relatively cheap to care for and are necessary to subsidize older and more expensive enrollees.

While the administration isn't releasing numbers, of the six states that are keeping score, only 28 percent fit into the young and healthy demographic.

Fox News spoke with some Los Angeles residents in that age group, who said for them, buying health insurance just doesn't make economic sense.

"A lot of people can't afford it the way it is these days," one young man said.

"I think a lot of young men my age nowadays probably don't really look into it," said another.

Though the government plans to start fining people who don't sign up for coverage by March 31, 2014, experts say the numbers simply don't add up for many young people.

Faced with expenses for rent, a car payment, auto insurance, food, and clothing, many would rather spend any leftover cash on travel, entertainment and even beer than drop $100 to $200 a month on something they don't think they'll need.

Outside a Starbucks in Santa Monica, a 20-something observed, "six or seven of my friends are uninsured right now." A friend added, "I hate the fact that I'm going to have to pay the fine, but I'll pay the fine."

That's because statistics show, the average uninsured male between the ages of 21 and 35 will see a physician as seldom as six times during that 14-year period, according to Carl Schramm, a former insurance company executive who now teaches economic policy at Syracuse University.

For those who are insured, the New York health care consultant company Milliman says men 19-34 years old will see a doctor 1.8 times a year compared with women, who will on average see a doctor 3.6 times. The two data points suggest many young people may not see health insurance as necessary.

"Most of them have zero health costs. In fact, the median health care spending for this group is exactly zero," said economist Douglas Holtz-Eakin, former head of the Congressional Budget Office.

"Literally if they do the arithmetic, 80-85 percent will just say no ... pay the penalty and stay out of the Affordable Care Act," he said. "There's a long tradition of the young invincibles not buying insurance. Those who did buy insurance in polling that we've looked at said that if their premiums went up as much as 30 percent, they'd drop it."

And for many, that is the case, since many had the minimal, catastrophic-care type policies that ObamaCare banned. Now they are being asked to buy better, albeit more expensive, health care policies.

Holtz-Eakin says if the administration prices young people out of the market, taxpayers will have to kick in the difference.

"If the age group doesn't sign up at all then the so-called exchanges are filled with very high-costs patients and the government will have to subsidize them extensively," he said. "We'll end up with a government run program for very sick people, something we've already had."