“Eat all you want and still lose weight” boast the ads for Akavar 20/50, one of the most heavily advertised new weight-loss supplements on the market.

Their promise gets caught in your head, not simply because it’s repeated – no, shouted – multiple times, but because, at this time of year, it sounds a lot better than going to the gym.

With New Year’s workout kick winding down and months to go before bikini season, midyear sees a dramatic slump in gym activity, according to a study in the Journal of Clinical Psychology. So why don’t we all just pop a pill, order a pizza and commence the fat burning? Because it’s hard to believe such a miracle drug exists.

Akavar’s own research chemist, Dr. Nathalie Chevreau, was happy to fill us in on a 2001 report featured in the Journal of Human Nutrition and Dietetics that stated 24 people who took Akavar lost an average of 11 pounds in 45 days, while 23 who were given a placebo lost nearly no weight at all.

In fact, she even takes it herself.

“I take one serving, which is two tablets, once in the morning to make sure I’m not too hungry for the day,” says Chevreau of the pills, which cost $39.99 a bottle. “There is a slowdown of the stomach emptying into the intestine, so you have an increased sense of fullness.” She attributes the process to three active herbal ingredients, yerba mate, guarana and damiana.

But that’s not necessarily a good thing, say other experts.

“If it’s decreasing the appetite and causing you to eat less, you’re body goes into starvation mode and starts to burn lean tissue and store fat. The active ingredients are stimulants, and no one really knows what the safe doses are for any of these herbs in the long term,” counters weight-loss expert and non-Akavar affiliate Dr. Dave E. David, who equates the caffeine levels in one dose to 3-1/2 cups of coffee.

“Taking more than 250mg of caffeine has been implicated in insomnia and high blood pressure,” says nutritionist Thomas Von Ohlen, who works with thousands of patients to address the hundreds of different reasons for weight gain.

“The idea of one cure-all is absurd. Losing weight by taking diet pills and going to Dunkin’ Donuts all day long is a biochemical impossibility,” he adds. “The basic rule is, if it sounds too good to be true, it is.”

Meanwhile, Akavar’s ad claims: “We couldn’t say it in print if it wasn’t true.”

Well, actually, they pretty much can, as there’s no federal agency that reviews advertisements before they appear.

“They’re about as bold as you can be,” says lawyer Scott Shepherd of the outrageously brazen ads.

His firm, Shepherd, Finkelman, Miller & Shah, LLC, has filed a class-action lawsuit against the company, set to go to trial in 2010. “We filed our case in November 2007 based on consumer fraud claims,” said Shepherd, whose firm has successfully settled a $16 million suit against Rexall Sundown Inc., for weight-loss product Cellasene and a $12 million suit against the now-defunct Dr. Phil-endorsed Shape Up! diet supplements.

Meanwhile, the Federal Trade Commission was unable to confirm whether any investigation is pending.

One thing is clear: Getting off your behind and heading to the gym is looking better and better.