Q. Can Lipozene help me lose weight without dieting and exercising?

A. Lipozene is a supplement, advertised on infomercials, that promises weight loss without dieting or exercise. I am always suspicious of products making these types of claims.

According to the infomercial, "Lipozene is clinically proven to reduce body fat and weight." They claim that in a "university double blind study, participants not only lost weight, but 78 percent of each pound lost was body fat." This study hasn't been published in any scientific journal nor is it available on the company's Web site.

The company that makes Lipozene has a huge credibility problem. The Federal Trade Commission took legal action against it several years ago for making false, unproven claims about Propolene and Fiberthin (which coincidentally have the same active ingredient as Lipozene). They claimed these products would cause rapid, substantial weight loss without the need for diet and exercise; that weight loss would occur no matter what the consumer ate; and that weight loss would occur in all cases. They were forced to pay $1.5 million back to customers. Would you trust a company with that history?

The active ingredient in Lipozene is a soluble fiber called glucomannan. Like other soluble fibers, glucomannan works by taking up space in the stomach, thereby making you feel full.

Some small studies on glucomannan do show weight loss of approximately three to six pounds in eight weeks in obese subjects. That's less than one pound per week! Not a huge amount of weight loss.

Lipozene is an expensive way to get your fiber. A month's supply costs $45 to $90, depending on dosage. The company recommends four pills daily at $90 per month if you need to lose at least 30 pounds.

Glucomannan is derived from konjar flour, which is found in such Japanese foods as shirataki noodles and konnyaku. Glucomannan supplements are sold online and in health-food stores for a much lower price than Lipozene.

Food sources of fiber can also help you lose weight. Good sources include whole-grain cereals such as Raisin Bran or Fiber One. Other sources include starchy beans, vegetables and fruits.

Although fiber supplements may help some people lose a little weight, they will work better if accompanied by healthful changes in diet and exercise.

Amy Tousman is a registered dietitian and certified diabetes educator. Send your questions to: Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; e-mail islandlife@honoluluadvertiser.com. This column is not intended to provide medical advice.