A FRUIT-and-vegetable-based cleansing product Marie Lebair O'Brient uses about every three months makes her feel like she's getting her eating habits back on track.

After following the vegan, gluten-free Kaeng Raeng cleanse program for three days, her taste for salty foods diminishes. She feels more "regular" and is motivated to eat more healthfully. The regimen replaces all meals with a shake and all snacks with raw fruits and vegetables. It's worth the $60 investment each time, she says, to detox and lose a little bit of weight.

"It's a regimen of a few days where I am eating things that are really good for me," the Moraga resident says. "I am amazed at how good I feel afterward."

In the past couple of years, cleanse programs -- everything from the do-it-yourself lemon juice and maple syrup Master Cleanse to designer cleanses such as Kaeng Raeng developed by a Stanford grad -- have become the rage for people who want to lose weight, eliminate toxins from their bodies and gain some oft-needed eating discipline. Hollywood elites such as Beyoncé Knowles and Ryan Seacrest say they've lost weight using them, and Gwyneth Paltrow says a 21-day regimen she regularly follows helps give her "mental clarity."

Depending on the program -- and there are hundreds if not thousands on the market -- anecdotal reviews are generally shining. But health professionals warn that people are wasting their money on cleanses and, at worst, they are risking their health.

Unlike some cleanses that promise dramatic weight loss in mere days with the help of starvation fasts or added stimulants, there's nothing sneaky or nefarious about Lindsay Reinsmith's Kaeng Raeng cleanse or the CAN CAN Cleanse developed by San Francisco's Teresa Piro.

Reinsmith's Kaeng Raeng follows the principles of a raw vegan diet. A cleanser uses her powders -- which contain more than a full serving of fruit and fiber, lean protein, probiotic cultures, amino acids and vitamins -- in shakes, and supplements those shakes with raw fruits and vegetables for three to six days. And that's it. No coffee, no alcohol, no cupcakes or french fries. A healthy dose of water is also prescribed.

"What Kaeng Raeng does is help people get on the right track for long-term health," Reinsmith says. "It gives people the chance to experience plant-based living. When you're going on a detox, when you're abstaining from meat, you get a glimpse of how your body feels in that lifestyle."

Reinsmith says most people turn to Kaeng Raeng when they've "jumped off the wagon," meaning they've found themselves consuming too much fast food, too much salt or sugar and not enough fruits and vegetables.

Piro says her $175 CAN CAN Cleanse -- a three-day liquid cleanse program that includes organic fresh fruit and vegetable juices, soups and teas -- is a tool to reset the mind and body.

Prompting change

"People tend to make some realistic and healthy changes to improve their diets after the cleanse," she says.

And although Piro says the cleanse is not a weight-loss solution, "this is a great way to jump-start (a weight loss program)."

People report their cleanses have made them feel lighter. Users notice changes in their hair and skin. Sugar and salt cravings subside, and energy levels increase.

Providers of cleansing products, including Kaeng Raeng and CAN CAN Cleanse, say the process eliminates toxins from the body. And some cleansing proponents can be pretty convincing.

"We're starting to understand the impact that toxins are having on our bodies and their contribution to almost every type of illness that we're seeing, especially obesity and diabetes and cancers and neurological diseases," says Cory Reddish, a Mill Valley-based licensed naturopathic physician who offers a two-week personalized cleanse for $395. "When I say toxins, we're talking not only about chemicals, pesticides and PCBs but also things we are eating."

Toxins abound

Add the chemicals found in the air and water with chemicals used in home cleaning products, for example, and additives and preservatives in our food, Reddish says, and you'll find your body is full of toxins. Cleanses, she says, help remove some of those toxins. The people who participate in her Essential Cleanse, which includes classes, herbal supplements and a detox diet, lose weight and feel much better, she says.

"People start thinking more clearly, their energy is better, their mood is better after a cleanse," she says. "It's a result of decreasing the total toxic load in the body."

But is it necessary?

Thomas Hargrave, a doctor with Alta Bates Summit Medical Center who specializes in the gastrointestinal tract, is clear about claims of toxin elimination by cleanse proponents.

"It's ridiculous voodoo. All the people who are pushing this stuff have no medical training, and they are basing their claims in these phony ads where they show toxic stuff building up in colons," he says. "There are no toxins in colons. There is no health benefit and no cleansing benefit."

Although she says that eating a diet with lots of fruits and vegetables is great for you, Keri Gans, registered dietitian and spokeswoman for the American Dietetic Association, agrees that cleanses cannot deliver on all the promises their proprietors make.

"Anything will feel better after a couple days of not eating pure junk," she says. "And I claim that people who feel better do so because of what they're not eating, and they are not eating food very high in fats and very high in sugar."

Toxins, she says, are naturally eliminated by bodily functions.

"Our bodies are normally cleansing every day. That's why we have livers. I encourage people who feel like they need to clean out their system to eat fiber. Eat plenty of fruits and vegetables and whole grains every day," says Gans, author of "The Small Change Diet" (Gallery, $15).

As for permanent weight loss, Gans has doubts.

Do it yourself

"Quick weight loss usually means you haven't changed any of your behaviors," she says. "You will gain all that weight back and then some because you haven't learned anything from your actions."

Save your money and make your own fresh fruit juices and smoothies says Joan Frank, director of the Didactic Program in Dietetics at San Francisco State University.

She warns that cleanses should not be used by children or diabetics, and even healthy people should contact their doctors before they use them.

Frank adds it's best to avoid toxins rather than relying on a cleanse to flush them out. Buy meat with no antibiotics or hormones added. Use the Monterey Bay Aquarium's Seafood Watch program (www.montereybayaquarium.org) to find out which types of seafood have high levels of mercury and other toxins. Eat organic fruits and veggies or visit the Environmental Working Group (www.foodnews.org) to find out which produce has the most and least amount of pesticides used in production.

"The other thing to avoid is processed foods," Frank says. "There are so many benefits to just eating whole foods, fruits and vegetables, lean meats and poultry. It's nothing dramatic, but it really works."

  • To learn more about the Kaeng Raeng Cleanse, call 650-646-5474 or visit www.kaengraeng.com.
  • To learn more about the CAN CAN Cleanse, call 415-439-0035 or visit www.cancancleanse.com
  • Homeopathic doctor Cory Reddish can be reached at 415-383-3716. Her website is www.drcory.com
  • American Dietetic Association spokesman and nutrition expert Keri Gans' book, "The Small Change Diet," retails at $15 and can be found at most major bookstores or online.
    Visit the American Dietetic Association at www.eatright.org for information on nutrition and healthy weight loss. The website can also help you find a local nutritionist.