30 Fad Diets: Do They Work or Are They Just Wacky?

It's that time of year again. The holidays are winding down, winter has set in, and your waistline has gotten larger. You vow to get more exercise, lose weight, be healthier in the new year. But before you do something crazy, like insert a feeding tube up your nose (there's a diet for that) here's a quick review of some fad diets.

Fad diets are usually recognizable by certain criteria, according to a 2004 paper by the University of Kentucky Cooperative Extension. They often involve miracle foods, bizarre quantities of one type of food, have rigid menus and tout rapid weight loss. They rarely include any type of increased physical activity.

Some popular categories of fad diets include low- or no-carbohydrate diets popularized by the Atkins Diet; high carb, high fiber diets that avoid proteins and fats; liquid diets, diet pills, extreme low-calorie diets, novelty diets that promote specific foods, and pre-measured diets, such as Jenny Craig or Nutrisystem.

Some of these diets use valid concepts or have strategies that may work if part of an overall healthy diet and exercise plan. Others...not so much.

So, before you head out to buy a state-of-the-art juicer, fill your pantry with superfoods and weight-loss shakes or buy a tapeworm pill (more on that later), remember the common themes that most doctors and nutritionists preach when it comes to weight loss. Eat a variety of healthy foods, don't eat too much, and exercise. This list may actually inspire you.

Here are 30 fad diets.

Alkaline Diet
Alkaline Diet

Alkaline Diet

This diet was based on the idea that different types of food can have an effect on the pH balance of the body and that the change in pH can be used to treat or prevent disease. Alkaline promoting foods included fruits, vegetables, nuts and tofu, while 'acid' foods such as dairy, meat, eggs and grains are avoided. According to WebMD, food doesn't really affect your blood pH, but eating fruits and vegetables and avoiding sugar, alcohol, and processed foods as dictated by the diet isn't a bad idea.

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The Baby Food Diet
The Baby Food Diet

The Baby Food Diet

This diet calls for replacing one or two meals or snacks a day with baby food. The little jars of bland baby food range in calories from about 20 to 100. It will likely reduce your calories, or turn you off food altogether.

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The Beverly Hills Diet
The Beverly Hills Diet

The Beverly Hills Diet

This was a novelty diet from the 1980s. Food must be eaten in the right order. Each day starts with eating an enzyme-rich fruit, as much of this fruit as you like, but you have to wait at least one hour before eating another fruit. While the diet may promote rapid weight loss, it is nutritionally inadequate and doesn't promote permanent change in food habits or body weight, according to the University of Kentucky.

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Blood Type Diet
Blood Type Diet

Blood Type Diet

These diets are advocated by several authors who claim that blood type is the most important factor in determining who should eat what, and recommends a distinct diet for each blood type. The theory is that blood type O, for example, evolved earlier than the other types, so type O people should eat a high-animal-protein caveman diet. A 2013 study said that blood type diets lack supporting evidence.

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The Cabbage Soup Diet
The Cabbage Soup Diet

The Cabbage Soup Diet

This extreme low-calorie diet involves heavy consumption of a low-calorie cabbage soup over seven days. According to WebMD, weight loss is mostly water, and people likely gain it all back quickly.

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Detox Diets
Detox Diets

Detox Diets

Detox diets claim to purge contaminants that we take in from food and the environment, such as artificial flavors and colorings, pesticides, and preservatives. One 2014 paper said there is very little clinical evidence to support the use of these diets, and that no trials had been conducted to assess their effectiveness.

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Dexatrim/ Diet Pills
Dexatrim/ Diet Pills

Dexatrim/ Diet Pills

Although the formula is different now, the appetite suppressant Dexatrim once contained phenylpropanolamine, a decongestant, and ephedra, an amphetamine-like compound. The FDA banned ephedra in 2004; it was linked to raising blood pressure and increasing the risk of heart problems and stroke.

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The Drinking Man's Diet
The Drinking Man's Diet

The Drinking Man's Diet

The most attractive thing about this diet is probably its title. It's essentially a low-carbohydrate diet, that, according to the University of Kentucky, can promote rapid initial weight loss but can cause weakness, ketosis and poor stamina. The diet is high in fat, and much of initial weight loss is water.

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The Feeding Tube Diet
The Feeding Tube Diet

The Feeding Tube Diet

This diet, also known as the K-E diet, involves inserting a feeding tube through your nose to your stomach for 10 days. Dieters get their 800-calorie-a-day diet powder, which has no carbohydrates, through a portable pump that they carry around. In 2012, CNN reported on a bride who used the diet to lose 10 pounds before her wedding day. One doctor told CNN that risks associated with a feeding tube include insertion trauma, septum damage, perforated throat, lung damage, and GI bleeding.

Photo: Cancer Research UK / Wikimedia Commons

Formula Diets
Formula Diets

Formula Diets

Liquid formula diets are supposed to supply all nutrients needed at a controlled calorie level, usually around 400 calories. These diets involve drinks such as Slimfast, Optifast, or the Cambridge Diet drinks. Such diets tend to eliminate behavior cues and food decisions, so dieters don't learn to modify behavior for long-term success, according to the University of Kentucky.

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"The 4-Hour Body"
"The 4-Hour Body"

"The 4-Hour Body"

Essentially a low-carb diet, the book advocates the "slow-carb diet", which calls for a focus on "slow carbs" and allows one "cheat day" a week. It also calls for living on just a few hours of sleep by breaking sleep into six rigorously-scheduled 20-minute naps each day, according to an article in Harvard Business Review.

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Fruitarianism
Fruitarianism

Fruitarianism

This is a restrictive diet consisting of usually 75% fruit. Actor Ashton Kutcher adopted the diet for a month to prepare for his film role as Apple CEO Steve Jobs, who spent some time on the diet. Kutcher said he ended up in the hospital for two days, according to US News. The diet is sometimes adopted for religious or ethical reasons. Some fruitarians will eat only what falls naturally from a plant, so as not to kill or harm the plant.

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The Grapefruit Diet
The Grapefruit Diet

The Grapefruit Diet

The theory goes that grapefruit contains a special enzyme that burns fat. The diet has bounced around since the 1930s. You eat grapefruit three times a day with each meal. According to a 2008 Health article, the fruit likely fills you up and may keep you from eating too much, but it's not a fat burner.

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Israeli Army Diet
Israeli Army Diet

Israeli Army Diet

This one became popular in the 1970s. It was an extreme low-calorie diet in which the same food would be eaten for two days at a time, according to Freedieting. Apples for two days, cheese for two days, chicken for two days, and salad for two days. This is not how the Israeli army eats.

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Intermittent Fasting
Intermittent Fasting

Intermittent Fasting

This is a diet growing in popularity that involves cycling between a period of fasting and non-fasting, either for whole days or a certain number of hours each day, (known as time-restricted feeding.) People using time-restricted feeding might eat only between noon and 8 p.m., for example.

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Juice Fast
Juice Fast

Juice Fast

This one is easy to remember: drink only fruit and vegetable juice, no solid food. Juice fasts generally fall under detox diets, but claim weight loss. It's a good way to get your fruits and vegetables in, but juicers usually remove the fiber that you need. According to WebMD, these diets lack protein, and your hunger can backfire and lead to temptation.

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The Junk Food Diet
The Junk Food Diet

The Junk Food Diet

An Instagram user said he lost six pounds eating nothing but gas station snacks for a month. According to Business Insider, junk food diets involve eating just one food, such as pizza, ice cream, or cookies, resulting in miraculous weight loss. Needless to say, such diets are nutritionally inadequate, and don't promote permanent change in food habits or body weight, according to the University of Kentucky.

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Lamb Chop and Pineapple Diet
Lamb Chop and Pineapple Diet

Lamb Chop and Pineapple Diet

This diet is exactly what it sounds like. It was popular in the 1920s when it was adopted and promoted by Hollywood celebrities. Supposedly, the acid in the pineapple would absorb the fat from the lamb chops. Nutritionists panned it.

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The Last Chance Diet
The Last Chance Diet

The Last Chance Diet

This is a liquid protein diet, described in a 1976 book that sold 2.5 million copies. According to a 1977 People article, it turned out the liquid protein consisted of chemically predigested cow hide and tendon, artificial flavoring and sweetener, and the Food and Drug Administration was looking into more than 30 cases of people who died while on the diet.

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Macrobiotic Diet
Macrobiotic Diet

Macrobiotic Diet

The macrobiotic diet attempts to balance the supposed yin and yang elements of food and cookware. It's complicated, but the diet emphasizes combining things like locally grown whole grains, beans, vegetables, seaweed, miso, tofu and fruit.

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Morning Banana Diet
Morning Banana Diet

Morning Banana Diet

People in Japan went bananas over this one, Time reported in 2008. Breakfast consists of as many bananas as you want and a glass of room-temperature water, then eat anything you like for lunch and dinner. The diet was designed by a Japanese pharmacist whose husband was overweight. Whether the diet works or not, it was great for the banana industry.

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Paleo Diet
Paleo Diet

Paleo Diet

The recently popular Paleolithic diet, or caveman diet, allows only foods that might have been hunted or gathered by Paleolithic humans as far back as 2.5 million years. This includes fruits, vegetables, nuts, seeds, meats and fish. Paleo dieters eschew processed foods, dairy, most grains and refined sugars. According to the Mayo Clinic, the diet may have beneficial health effects, but there are no long-term clinical studies about the benefits or potential risks of the diet.

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Raw Food Diet
Raw Food Diet

Raw Food Diet

This involves eating raw fruits, vegetables, and grains. Some people believe cooking food makes it toxic, and destroys nutrients. Some eat unpasteurized dairy foods, raw eggs, meat, and fish on this diet. According to WebMD, one study found that people who followed a raw foods diet lost a significant amount of weight, but there is an increased risk of food-borne illness.

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The Rotation Diet
The Rotation Diet

The Rotation Diet

Both a novelty diet and and very low-calorie (less than 800 calories a day) this diet is supposed to raise metabolism by alternating low and moderate caloric intake for faster weight loss.

Although it may promote rapid weight loss, the diet is nutritionally inadequate, doesn't promote permanent change in food habits or body weight and can be dangerous if not supervised by a physician, according to the University of Kentucky.

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The Scarsdale Diet
The Scarsdale Diet

The Scarsdale Diet

This low-carbohydrate diet is similar to the Atkins Diet, calling for high protein and low fat and low carbohydrates, but also emphasizes fruits and vegetables. According to the University of Kentucky, the diet can promote rapid initial weight loss, but can cause weakness, ketosis and poor stamina.

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The Shangri-La Diet
The Shangri-La Diet

The Shangri-La Diet

Seth Roberts' bestselling book by the same name calls for consuming 100-400 calories per day of flavorless oil or unflavored sugar water between normal meals. The theory is that the flavorless oil reduces your desire for high-flavor foods, such as chocolate donuts, that make you fat. Though Roberts said he lost 35 pounds on the diet, all of the evidence is anecdotal.

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The South Beach Diet
The South Beach Diet

The South Beach Diet

The South Beach Diet was developed by Arthur Agatston and promoted in a best-selling 2003 book. It is a type of low-carb diet, because it prohibits simple starches, but doesn't count carbs, and emphasizes low-glycemic carbohydrates, high-fiber, unsaturated fats, and lean proteins.

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Superfoods
Superfoods

Superfoods

The term superfood is really just a marketing term, and technically, there's no such thing as a superfood, even though there are lots of nutrient-rich foods you'd probably enjoy eating, besides kale. Food safety organizations in Europe have said that the health claims marketers use to sell goji berry (pictured) hemp seed, chia seed, and wheatgrass are not scientifically proven and the unsubstantiated claims are prohibited in the E.U.

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Tapeworm Diet
Tapeworm Diet

Tapeworm Diet

Swallow a pill with a tapeworm egg inside. When the egg hatches, the tapeworm will grow inside your body and eat whatever you're eating. According to Healthline, people who (actually!) tried this reported "unpleasant side effects of a tapeworm infection." You may or may not want to know more of the side effects. The FDA has banned these pills.

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Zone Diet
Zone Diet

Zone Diet

The Zone diet restricts grains and starches. It was created by Barry Sears, a biochemist. On his website, Sears claims the diet reduces inflammation. If you are in "the Zone," you have optimized your ability to control diet-induced inflammation, which Sears says causes weight gain.

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