10 Diets That Just Don't Work

The acai (pronounced ah-sigh-ee) berry, once a no-name fruit from the Amazonian palm, has in recent years soared into the world's nomenclature for its health benefits. It's been promoted for its high antioxidant content and its ability to improve digestion, detoxify the body and slow down aging. It's also become popular as a dietary supplement to promote weight loss [source: Zeratsky].

The acai diet became popular after Dr. Nicholas Perricone lauded the berry's high antioxidant benefits on the Oprah Winfrey Show. There isn't an exact regimen for this diet, but the idea is to incorporate these supplements into your daily routine. The cost of using supplements ranges from $40 to 80 each month, and they can be bought in various forms, including as a juice or capsule. Keep in mind that the supplements aren't regulated by the U.S. Food and Drug Administration. And unfortunately, acai's health benefits, particularly those of weight loss, haven't been scientifically proven [source: Center for Science in the Public Interest].

Is this just an excuse to eat bacon all day? Not exactly, but the diet works by requiring people to drastically reduce their consumption of carbohydrates and replace them with protein, whether it's bacon, cheese or eggs. The idea is that overweight people tend to eat too many refined carbohydrates, or empty calories. Without carbohydrates, the body will then begin burning the fat that they initially produced.

However, nutritionists and doctors are concerned about a couple of aspects of this diet. The first is a process known as ketosis -- where the body burns its own fat stores as energy [source: Nordqvist]. The harmful side effects can be halitosis, constipation and even kidney and liver damage (unless the person consumes lots of fluids), since these organs have to work overtime to process the elevated levels of protein. Finally, carbohydrates have always been part a building block of a healthy diet that leads to sustained energy and healthy brain function [source: Hardy]. Without carbohydrates, you may be skinnier, but not necessarily healthy. And then what's the point?

Attack, cruise, consolidation and stabilization are the beginning stages of the Dukan Diet [source: Dukan]. These may sound more like the phases of a naval battle than those of diet, but they convey one point: Fat is the enemy and you're going to obliterate it. Here's how it works: Over a decade ago, a French physician named Pierre Dukan realized that if a person's food consumption is restricted to mostly lean protein, the pounds fall away. Yes, this may sound similar to the Atkins Diet [source: Zelman].

As with Atkins, nutritionists and doctors warn that by eliminating carbohydrates and restricting other foods, such as vegetables and fruit, you're also restricting your nutrient intake. Besides nutritional deficiencies, you may also end up with bad breath, fatigue and kidney problems. The bottom line is that while you may end up a few pounds lighter, don't expect to maintain this weight unless you've always preferred eating pork and oat bran.

Perhaps this diet sounds feasible since it mentions one of the body's most basic biological components in its title -- blood. Don't be fooled, though; there's no proof that this diet works [source: Hardy]. To be fair, it hasn't been disproved either. "From my understanding, health and wellness was the primary focus of this diet, and weight loss was a nice side effect, if you're able to master the food restrictions," says Hardy.

The diet is based on the notion that food intake should be determined by blood type (A, vegetarian; B, a balanced omnivore diet; AB, combination of food groups in moderation; or O, high protein), and that food proteins are digested differently depending on these various blood types [source: Lam]. Thereby, health problems can result from eating food that's not well matched to your specific blood type.

In the end, the type of diet that has proven to be the most healthy and reliable requires a combination of eating all the food groups in moderation and frequent, low-impact exercise.

Dr. Sanford Siegal, the inventor of this program, baked up his own version of a cookie, complete with fiber and essential amino acids, as a replacement for breakfast and lunch [source: Zelman]. All you need to do is eat four to six (for 500 calories) cookies each day, eat a dinner made up of lean proteins and vegetables (300 to 1,000 calories), and voila! You're on your way to shedding pounds … at least for the short amount of time you find cookies an enjoyable meal replacement.

One caveat, says dietician Hardy: Be wary of any diet that pushes the benefits of eating only one type of food or restricting your diet to a few items. While you may be able to drop the pounds in a couple of weeks, you'll feel unsatisfied and be hungry frequently. "It's the same as Slim Fast," continues Hardy. "Who really wants to drink a couple shakes or eat a couple cookies knowing that you're missing out on the opportunity to savor your food and let it nourish you?"

This is one of Hollywood's hottest diets. Celebrities such as Beyoncé, Ashton Kutcher and Demi Moore have waxed about the quick weight-loss benefits of the Master Cleanse. The only problem? This concoction of lemon juice, maple syrup and cayenne pepper was never intended as a weight loss plan. Instead, it was created as a body detox system to bring the body's pH balance from an acidic state to an alkaline, or healthy state [source: Master Cleanse].

Cleansing can help people reset their eating routine if they've gotten into bad habits. And while it may make them feel good, cleansing shouldn't be used as a diet plan. It can't be maintained and the weight will return along with regular food consumption.

People will go to great lengths to lose weight quickly, no matter how painful or madcap the plan. Here's the proof: The HCG diet involves daily injections or supplements of human chorionic gonadotropin (hCG) -- a pregnancy hormone that's been approved as an infertility treatment, but shows little evidence that it helps people lose weight [source: Nelson]. The hormone coupled with intense calorie restriction is at the heart of this diet. Sadly, severe calorie restriction can have deleterious health effects, including the inability to fulfill one's nutritional needs. Also, hCG's side effects may involve headaches, fatigue, irritability and male breast enlargement.

This vegan diet promotes the consumption of organic and natural foods such as fresh fruits, coconut milk, natural foods, seaweed, dried fruits, grains, beans, nuts and vegetables [source: WebMD]. There are definitely people who can consume raw food for extended periods of time and be fine and healthy. But most people find it extremely restrictive and have a hard time getting enough vitamin B12 and vitamin A. The reason for this is that some nutrients, such as lycopene (an important antioxidant for prostate and blood health that's found in tomatoes), aren't available until the food is cooked. The same goes for the iron found in leafy greens. "I would never, as a dietician, recommend that someone follow a raw foods diet," says Hardy. "But, if you still decide to, you have to be very committed to food preparation."

One of the more effective and less controversial fad diets, the Zone Diet calls for you to maintain a fixed ratio of proteins (30 percent), carbohydrates (40 percent) and fats (30 percent). This makes it easy to follow. Even so, nutritionists and dieticians fear that the Zone promotes eating high amounts of saturated fat, which can be harmful to your cholesterol and can lead to heart disease over a long period. This diet also completely ignores the fact that people may still get hungry and lack energy [source: WebMD].

This diet goes by many names: the Paleo Diet, the Caveman Diet, the Stone Age Diet or the hunter-gatherer diet. Whatever your preference, this eating plan is based on the food consumed during the Paleolithic era that ended about 10,000 years ago. This means that the suggested foods can be hunted, fished or gathered. This includes foods such as pork, seafood, eggs, fruits, nuts and vegetables. Foods to avoid include grains, legumes, dairy products, salt, refined sugar and processed oils.

The only downfall to this diet, says Hardy, is that once again the food limitations make it difficult to maintain. There may also be problems with receiving all the necessary nutrients derived from legumes, whole grains and reduced-fat dairy products [sources: Zelman; Hardy].

Want to learn more about losing or maintaining your weight? There's lots more information on the next page.