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So-called detox diets, like the Master Cleanse, are seen as a quick way to lose weight, especially among celebrities like Oprah and Gwyneth Paltrow. But what is a detox diet? Is it a healthy way to cleanse your body, or a dangerous way to lose weight? FITNESS reports on popular detox diets, how they work, and who's doing them.

What Is a Detox Diet, and Who Needs It?

Yo-yo dieter Oprah went on the 21-Day Cleanse back in the summer of 2008, singer Beyonce Knowles has admitted to following the Master Cleanse to shed 20 pounds for her movie role in Dreamgirls, and actress Gwyneth Paltrow sent out a newsletter this January from her lifestyle Web site, GOOP.com, touting a weeklong elimination diet. "I need to lose a few pounds of holiday excess," she wrote. "Anyone else?"

Such celebrities seem to buy into so-called "detox diets" as a way to drop pounds fast. But the real premise of a true elimination diet or cleanse program (both types of detoxification diets, or "detox diets" for short) is to facilitate the removal of toxins and pollutants from your body. How? By cutting out your intake of contaminants, so you'll gradually eliminate unhealthy substances like pesticides, smog and pollution, alcohol, and caffeine from your body.

"There are a lot of people who believe that because we live in a world with so many environmental pollutants and medications that people are taking, the liver is overstressed," explains Mary Jane Detroyer, a New York-based registered dietitian and exercise physiologist. "The whole idea of a detox diet is to rid toxins from the body, because the liver is overloaded and needs some outside help."

But do our bodies actually need a special diet to cleanse itself? Not really, says Dawn Jackson Blatner, an American Dietetic Association spokesperson and FITNESS advisory board member. "Our bodies have organs such as the liver, kidneys, skin, lungs, and digestive system to remove these unnecessary substances every day without the help of any special detox diet or potions to help it along."

Compared to how many people try fad detox diets, few people actually need it. (To see if you do, Detroyer recommends getting your liver enzymes checked out by your physician. "If they're elevated, that means your liver is stressed," she says. Several factors can cause elevated levels, such as medication, excessive alcohol consumption, or being overweight.)

However, if you still feel inclined to embark on a detox plan, dieter beware: "For most healthy people, doing a detox for a few days won't lead to any long-term health problems," says Blatner. "However, for someone who has conditions such as diabetes, heart disease, kidney disease, digestive issues, or women who are pregnant, children or teens, and elderly, these extreme changes to their diet can mean anything from dizziness to fainting to coma since the diets affect electrolyte and blood sugar balance."

And even if you don't suffer from any of those conditions, taking on a long-term cleanse (ahem, Oprah) can lead to a host of other problems, such as vitamin and mineral deficiency and muscle breakdown — not really surprising when you're doing something extreme like drinking nothing but lemon water with maple syrup and cayenne pepper for 10 days, as the Master Cleanse encourages.

Still, there may be one good side effect from starting a detox plan: "A healthy person following a short-term detox diet may get a bit of a mental jump start into eating healthier and exercising for the rest of the year," Blatner concedes.

Celebrity Detox Diets You Should Try - and Avoid

So which detox diet could be right for you? FITNESS took a hard look at a few popular detox diets, assessing each one based on the nutritional value, liver-cleansing value, and their ability to help you start a long-term healthy eating habit. Read on for our findings.

Note: Detroyer stresses that if anyone is going to try any of the plans listed, it should be approved by a doctor first, especially if the person is taking a medication or has a medical condition.

Master Cleanse

Also known as: The Lemonade Diet, The Maple Syrup Diet

Who created it: Stanley Burroughs, an alternative health enthusiast and author of The Master Cleaner, published in the 1950s. Burroughs, however, was convicted of practicing medicine without a license in 1960, and faced other criminal charges in 1984, including illegal sale of cancer treatments and second-degree felony murder. The latter charge stemmed from Burroughs treating a man for cancer by feeding him his touted lemonade formula, exposing him to colored lights, and giving him deep massages. The man agreed to Burroughs' treatment, but became significantly sicker under Burroughs' care, and ultimately died. Eventually, the murder charge was reduced to involuntary manslaughter.

What it promises: To cleanse the body of toxins and obliterate cravings for junk food, alcohol, and tobacco.

How it works: For 10 days you'll drink 6 to 10 glasses of "lemonade" (made of water, lemon juice, maple syrup, and cayenne pepper) a day. You'll also drink a glass of salt water in the morning and a laxative tea at night.

How much it costs: A variety of retailers sell Master Cleanse kits at various price points. Or you can just go to the grocery store and buy the ingredients yourself.

Who's tried it: Singer Beyonce Knowles, actor Jared Leto

FITNESS says: Avoid it. "This can be dangerous," says Detroyer, citing the low-calorie intake and lack of research to substantiate the diet's claims. "It could be stressful on your GI tract because you don't eat any solid food for 10 days. And I don't know why you would need a laxative while on the fast if it's an all liquid diet."

Martha's Vineyard Diet Detox

Also known as: 21 Pounds in 21 Days

Who created it: Roni DeLuz, RN, ND, a licensed naturopath and founder and director of The Martha's Vineyard Holistic Retreat at the Martha's Vineyard Inn.

What it promises: Though it claims not to be "a so-called 'weight loss diet'" on its Web site, it also claims that you'll lose 21 pounds in 21 days on their 3-week "MasterFast" plan. It also claims to give you more energy and lower blood pressure.

How it works: No solid food here: you'll drink fruit and veggie juices, protein shakes, herbal teas and cleansing drinks, broths and soups, and lots of water. The plan also encourages the intake of supplements and vitamins (which can be bought off the Web site). Users are also instructed to have weekly colonics and coffee enemas.

How much it costs: $199 for the 21-day program and 9-day "maintenance package." Does not include the price of the book, enzyme pills or (necessary) juicer. Book retails for $24.96.

Who's tried it: Robin Quivers, Howard Stern's radio sidekick

FITNESS says: Avoid it. Three weeks with no solid food is "too extreme," says Detroyer. Plus, "nobody needs enemas or colonics. There is absolutely no research to support [their benefits], and I think it could be dangerous. It could dehydrate you if you are not adequately replacing lost fluids."

Liver Cleansing Diet

Who created it: Sandra McRae, MD, a licensed doctor in Australia, who goes by the pen name Sandra Cabot.

What it promises: To improve liver function, which will help a variety of ailments, including bloating, digestion, fatigue, moodiness, IBS, high cholesterol, allergies, headaches, and sugar cravings.

How it works: The 8-week program advises you to eat lots of raw fruits and vegetables (no cooking), some proteins (grains, raw nuts, seeds, legumes, eggs, skinless chicken, lean red meat, fish). Avoid all dairy products, fried foods, processed foods, excessive alcohol, and refined sugars. Drink at least 2 liters of water, raw juice, or tea every day. Eat organic foods if you can. Take daily liver tonic capsules (which can be bought on her Web site).

How much it costs: A variety of tablets are sold on her Web site, including liver cleaning capsules at $50 for 250. Book retails for $19.95.

FITNESS says: Avoid it. Though the eating plan on its own could be healthy if the follower is vigilant about calcium intake (thereby compensating up for the lack of dairy in the plan), the addition of liver cleansing pills is a red flag. "This plan is recommended for people who have liver problems. But how do people know if they have problems?" says Detroyer. "This plan could be good for anyone whose liver is stressed, but they should be working with their physician for that." Following this diet without medical consultation could be harmful in that the herbs found within the pills could interfere with medication or trigger an allergic reaction.

The 3-Day Fruit Flush Diet

Who created it: Jay Robb, a nutritionist and former personal trainer.

What it promises: A 10-pound weight-loss in 3 days.

How it works: On Day 1, drink protein shakes. On Day 2 and 3, you'll eat fresh fruits every two hours (no frozen, dried, or canned fruits allowed) and a dinner of raw, nonstarchy veggies and a bit of lean protein. Avoid cooked vegetables, caffeine, alcohol, most fats, sugars, and all beverages except filtered water. Do not exercise during the three days, although "light walking for 20 minutes may be okay," according to the Web site.

How much it costs: Book retails for $5.00.

FITNESS says: Be wary of it. Yes, you will lose weight on this diet because of the low-calorie food intake, but it'll mostly be water weight. But will it detox you? "Well, you're not going to be putting a lot of artificial ingredients, saturated fat, sugar and processed grains into your body except for the pesticides and fertilizers used to grow the fruits and vegetables, so in a way, yes," says Detroyer. However, over an extended period of time, you may miss out on nutrients. "There's a lack of fat in this diet, so after a long period of time you may not be absorbing the fat soluble vitamins A, D, E and K."

The Fast Track One-Day Detox Diet

Who created it: Ann Louise Gittleman, PhD, CNS, a nutritionist.

What it promises: The diet claims to flush toxins from your body, boost your metabolism, and help you lose 3 to 8 pounds.

How it works: This diet actually lasts 11 days, not one day: there's a 7-day preparation "prequel" stage, a one-day fast, and a 3-day "sequel" stage. Prepare to get intimate with your toilet: during the preparation stage, you'll eat one to three of the "liver-loving" foods or supplements (e.g., broccoli, leafy green veggies, oranges, Brussels sprouts, eggs), at least one "colon-loving" food or supplement (e.g., carrots, apples, berries), two servings of lean protein, one or two tablespoons of flaxseed or olive oil, and plenty of water. Avoid all fats, sugars, refined carbs, gluten-containing foods, alcohol, caffeine, and drugs. During the one-day fast, you'll alternate drinking one cup of water and one cup of "Miracle Juice" (made with water, unsweetened cranberry juice, cinnamon, ground ginger, nutmeg, fresh-squeezed orange juice, and stevia), downing one cup of fluid every hour the entire day — a huge amount of fluid. You'll also take one colon-loving supplement in the morning and one at night. The sequel stage is like a three-day version of the first stage, except you'll also be eating at least one daily serving of raw sauerkraut or lowfat yogurt with live, active cultures.

How much it costs: Book retails for $12.95.

FITNESS says: Try it, but proceed with caution. This diet could make you feel gassy and bloated, thanks to the fibrous foods, and you'll likely be making many a trip to the bathroom. However, this plan does include healthy oils, protein, and fruits and veggies. "For the short term, this really can't hurt you because you're only fasting for one day," says Detroyer.

Dr. Joshi's Holistic Detox

Who created it: Nish Joshi, a licensed physician in conventional medicine who's also studied holistic healthcare, and founder of The Joshi Clinic.

What it promises: To return your body to its natural alkaline balance by altering the pH of your system with food. The diet will improve your metabolism and break your cravings for toxins like caffeine, sugar, and salt.

How it works: During this 21-day detox, you'll eat white meat, brown rice, dark green vegetables, certain fish, gluten-free breads, and soy products. Avoid acidic foods like red meat, most dairy, fruit (except bananas), wheat, yeast, alcohol, sugars, coffee or tea, or artificial foods or flavorings. Drink lots of water.

How much it costs: Book retails for $19.95.

Who's tried it: Gwyneth Paltrow

FITNESS says: Try it, but proceed with caution. For the most part, "this is a healthy diet," says Detroyer. If you do follow this plan, make sure you're consuming adequate amounts of vitamin C, a challenge since the diet bans most fruits. It's also important to eat the right dark, leafy green vegetables, such as spinach, broccoli, kale and asparagus, to ensure you get enough calcium, given the ban on dairy. However, "I don't know if it's sustainable for most people," says Detroyer, citing the lack of fruit. "It sounds a little too restrictive."

Gwyneth Paltrow's Latest Detox Diet

Who created it: Paltrow, who based it on the guidelines from her physician, Dr. Alejandro Junger, a New York-based cardiologist and raw food fan.

What it promises: A detoxification of the body.

How it works: Paltrow's diet itself is heavily plant-based with very little meat. A sample day's menu includes a glass of room-temperature lemon water and herbal tea in the morning, a blueberry and almond smoothie for breakfast, coconut water, a salad with carrot and ginger dressing for lunch, a handful of mixed pumpkin and sunflower seeds for a snack, and broccoli and arugula soup for dinner. Followers of the diet are also encouraged to do deep breathing or gentle yoga, ingest a few spoonfuls of extra virgin olive oil at night, drink half a cup of castor oil or take a mild herbal laxative if constipation occurs, and eat whole organic foods.

How much it costs: No cost.

Who's tried it: Gwyneth Paltrow

FITNESS says: Be wary of it. Detroyer says that deep breathing and yoga exercises can be beneficial, as "chronic stress causes elevated glucose levels and lipid levels, which are toxic to the body." Moreover, the diet itself has very good things in it. "Vegetable soup and smoothies are wonderful," she says. "But there's very few calories in there. If you're trying to sustain yourself working, you may become extremely lightheaded, shaky, and irritable." In addition to the problematic very low-calorie diet, the plan included olive oil and laxative suggestions, which Detroyer deemed unnecessary. "If people were to be eating the appropriate amount of fiber, which is about 25 to 30 grams a day from fruits, veggies, whole grains, beans, and drinking lots of fluid and getting regular exercise, most people won't be having [bowel] problems."

Foods to Eat, Foods to Avoid

Can't handle the maple syrup-lemon water-Cayenne pepper liquid diet? Can't afford organic fruits and vegetables for every meal? Don't know where to buy coconut water? The main problem with most mainstream cleanse diets is that they're unrealistic by design. However, eating a properly balanced diet is a detoxification of the body. So forget magic powders and starvation plans.

"The most effective 'detox' is drinking plenty of water, getting enough sleep, and eating a balanced diet of fruits, vegetables, whole grains, lean proteins, and healthy fats so that our own detox organs can keep us healthy," says Blatner. "What you do for a few days can't ever make up for how we live and take care of our body the other 365 days!"

If you feel the need to detox, here are some foods to avoid, according to Detroyer:

• Alcohol
• Caffeine
• Excessive sugar
• Unhealthy fats (butter, fried foods, saturated fat, Crisco, fatty meats)
• Processed foods (things that come out of boxes or have chemicals)
• Artificial sweeteners
• Excessive protein (which is hard on the digestive system)

Here's a sample day's worth of food that'll get your body back on the right track, as put together by Blatner:

Breakfast: Oatmeal with unsweetened almond milk, chopped walnuts, and chopped apple

Lunch: Whole-grain pita stuffed with white beans, fresh basil, and chopped tomatoes, with olive oil vinaigrette

Dinner: Salmon with quinoa and kale or broccoli, with lemon and pinenuts

Snacks: A low-fat plain yogurt with berries, or peanut butter and celery

Drinks: Plenty of water, unsweetened tea