The post-holiday season for many is signing up for gym memberships or purchasing exercise equipment to counteract holiday indulgences, but according to the U.S. Food and Drug Administration those looking to stay fit should stay away from more than two dozen different weight loss pills.

Weight loss pills are marketed as quick and healthy alternatives to spending hours on a treadmill, but an analysis by the FDA found 28 brands contain undeclared, potentially deadly ingredients not approved by the federal government.

“These tainted weight loss products pose a great risk to public health because they contain undeclared ingredients and, in some cases, contain prescription drugs in amounts that greatly exceed their maximum recommended dosages,” said Dr. Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research.

So far the FDA has labeled many of these items as illegal, even though they have been promoted by the manufacturers as containing natural or herbal ingredients.

Ingredients identified by the FDA include a controlled substance called sibutramine that causes seizures, high blood pressure, heart attack or stroke. The organization also found pills that contain rimonabant, which is not approved for use in the United States, and phenolphthalein, which health experts suspect causes cancer.

“Consumers have no way of knowing that these products contain powerful drugs that could cause serious health consequences,” said Woodcock.

A report by Espicom Healthcare Intelligence estimates that the weight loss drug market will be worth approximately $2 billion by 2010. This demand is only exacerbated by the fact that U.S. obesity rates are much higher than other developed countries.

While the market is saturated with hundreds of brands promising swift weight loss, health experts point out that there are natural alternatives to pumping the body full of damaging chemicals.

“You have to clean out the body naturally,” said Noneen Murdoch, an acupuncture physician with Natural Family Physicians in Cape Coral. “You can’t just speed up the metabolism or you’ll get high blood pressure.”

Complaints over the last five years have increased with consumers stating that the pills cause heart palpitations, dizziness or shortness of breath.

Murdoch said her center will prescribe Chinese herbs, such as hawthorn and fennel, in place of pills with harmful chemicals. These natural herbs increase metabolism, adjust the digestive system and are appropriate for all ages.

Healthy weight loss is much more than simply taking a supplement or pill, she said. A person’s diet and lifestyle has to be adjusted to assist in natural weight loss.

“We like to look at what the person is eating and why the person is overeating,” said Murdoch. “There is a lot more to weight loss than overriding the system with something that could have side effects.”

Those who are using one of the 28 brands listed by the FDA should immediately discontinue use and consult a health care professional. Serious adverse effects also should be reported to the FDA’s MedWatch.

In its report, the FDA determined that the following brands are “tainted” and should not be used:

— Fatloss Slimming

— 2 Day Diet

— 3x Slimming Power

— Japan Lingzhi 24 Hours Diet

— 5x Imelda Perfect Slimming

— 3 Day Diet

— 7 Day Herbal Slim

— 8 Factor Diet

— 7 Diet Day/Night Formula

— 999 Fitness Essence

— Extrim Plus

— GMP

— Imelda Perfect Slim

— Lida DaiDaihua

— Miaozi Slim Capsules

— Perfect Slim

— Perfect Slim 5x

— Phyto Shape

— ProSlim Plus

— Royal Slimming Formula

— Slim 3 in 1

— Slim Express 360

— Slimtech

— Somotrim

— Superslim

— TripleSlim

— Zhen de Shou

— Venom Hyperdrive 3.0