7 Extreme Diets, Ranked by Nutritionists

by Jessica Nelson, RDN, CPT


#RealTalk: Losing weight is a daunting, difficult task, and it takes time to see results. That’s probably why extreme diets that promise massive weight loss in a short period of time are so appealing. “Sure, I can consume only liquid for 10 days if I can lose 20 pounds,” you may think. (Trust me, I’ve been there.) But should you? Here are the most extreme diets according to nutritionists, with ratings based on how nuts they are. Take a look.

7 Extreme Diets Evaluated By A Nutritionist

Master Cleanse

Beyonce Master Cleanse - Extreme Diets - The Wellnest by HUM Nutrition

What it is: An all-liquid diet in which you only consume a concoction of water, maple syrup, lemon juice, and cayenne pepper. (Also known as the Beyoncé diet since the singer followed it to lose weight for her role in Dreamgirls.) You drink six to 12 glasses of the mixture every day for 10 days, explains Jessica Nelson, RDN, CPT. You’re also allowed to sip on salt water and an herbal laxative tea. (Editor’s note: Sounds like fun and as though it wouldn’t interfere with your job/life at all.)

Why people try it: To drop lots of weight, fast.

The reality: “This is honestly the worst fad diet. Not only is it devoid of all nutrients, but none of its health claims can be backed up,” says Alexandra Caspero, MA, RD, CLT, RYT. “After a few days (or day!) on the Master Cleanse, you can expect to be hangry, tired and grouchy.” That’s because the diet is so low in calories that your cells aren’t getting any energy.

“Calories are thought of in such negative terms, but we need calories in the form of energy to survive,” adds Caspero. Yes, you’ll drastically lose weight—but it’s not the weight you want to lose. “Water weight is different than fat loss, which is different than muscle loss,” Caspero explains. “When you reduce calories to almost nothing, you will lose weight mostly in the form of water and muscle loss.”

Her overall grade: “This diet plan gets a big fat F from me. You can expect most of the weight to return after you resume eating normal food.”

This is one (and perhaps the only) instance in which you shouldn’t do as Beyoncé does.

Juice Cleanse

Glasses of juice for juice cleanse

What it is: An all-liquid diet in which you consume only fruit and vegetable juices. The majority of juice cleanses involve drinking six to eight juices per day for up to 10 days.

Why people try it: To detox their bodies and lose weight quickly. Proponents of juice cleanses say that drinking juice gives your digestive tract a break and can help you lose weight, Nelson explains. “Other people may simply do it as a fast way to get in more fruits and vegetables.”

The reality: “Sadly, the juice industry has convinced the American public that drinking a green juice will help them detox the body. It isn’t the whole truth,” Caspero says. “Yes, juice contains nutrients in the form of fruits and vegetables, but so do whole foods.” You’re better off eating whole fruits and vegetables, which contain fiber that helps you feel full.

Plus, the high fructose content of most juices can make you feel bloated and can even cause diarrhea, adds Nelson.

“Lastly, juicing produces a lot of food waste. Imagine how much pulp you throw away for one eight-ounce juice. Skip the juice, eat the produce instead (and save the $8),” says Caspero.

Grapefruit Diet

Eating grapefruit for weight loss

What it is: You eat half a grapefruit before every meal. You eat your meals at normal times, but forego dessert, bread, and white vegetables while tripling your intake of meat and other vegetables. “Additional suggestions for the diet include going four hours between protein-based meals and starch-based meals,” Nelson says.

Why people try it: “It’s believed that grapefruits can help reduce appetite and promote weight loss by providing fat-burning enzymes,” Nelson says. There’s also the promise of a 10-pound weight loss in only 12 days.

The reality: “Eating the half grapefruit before a meal may help you eat less because of the fiber and water content found in the fruit. So, theoretically, it could help you lose weight overtime,” says Nelson.

“However, the diet doesn’t help you change your eating habits. So although you’re eating a healthy fruit more often in your diet, the meals that follow can continue to be not so healthy for you,” she adds. Plus, grapefruits interfere with many medications, so you should check with your doctor before adding them to your diet.


Vegetable soups for weight loss

What it is:Souping is basically juicing for the winter crowd,” says Caspero. “Instead of sucking down green elixirs, you’ll sip on ‘detox’ soups throughout the day.”

Why people try it: They see it as a healthier, quicker weight-loss program than juicing.

The reality: “While soup is a really great food and a healthy way to get nutrients in, soup cleanses tend to be quite low in calories,” Caspero says. Typically you’ll consume around 1,200 calories a day on a soup cleanse. But, Caspero says, most women need between 1,400 and 1,600 calories a day. “While you’ll lose weight with 1200 calories, it’s not very sustainable and you’re more likely to lose muscle mass,” she says.

Cabbage Soup Diet

Bowl of cabbage soup for dieting

What it is: This extreme diet hearkens all the way back to the 1950s. The theory behind this diet is that including cabbage soup in your diet regularly—in place of 1-2 meals a day—can help you shed weight,” says Toby Amidor, MS, RD, nutrition expert, and author of The Greek Yogurt Kitchen: More Than 130 Delicious, Healthy Recipes for Every Meal of the Day.

You eat cabbage soup every day for most—if not all—of your meals for seven days.

Why people try it: Since cabbage is a diuretic, people think that increasing their cabbage intake can help get rid of water weight.

The reality: “An updated version was released which is more in line with healthy eating patterns recommended by the dietary guidelines for Americans,” says Amidor. “Weight loss is about 1-2 pounds per week, which is in line with the NIH standards for a safe rate of weight loss,” she explains. But like most crash diets, it isn’t sustainable and you’ll likely gain back all the weight you lost and more. (Plus, all that cabbage soup has gotta make you… ahem… rather flatulent.)

Tapeworm Diet

A tapeworm for an extreme diet

What it is: You eat a tapeworm (or the larvae of a tapeworm), so it can grow inside you. (Anyone’s gag reflex kicking in yet?)

Why people try it: The tapeworm will reduce the calories that your body absorbs, so you can still eat the same amount and lose weight. “Many dieters think they will magically lose weight without any side effects and that it’s ‘no big deal,’” says Amidor.

The reality: There’s a literal parasite living in your gastrointestinal system. The tapeworm eats gobbled-up food and nutrients that you need. “You lose weight due to lack of nourishment, and develop symptoms such as nausea, diarrhea, fatigue, and abdominal pain,” she adds. Since the tapeworm is ingesting the nutrients you need, it can cause serious vitamin and mineral deficiencies with unpleasant side effects (like bone pain and anxiety, for example).

Decide you want that tapeworm out of you? You’ve got to give your doctor a stool sample, so they can determine the type of tapeworm you ingested. Then they’ll prescribe an anti-parasitic along with an antibiotic because, fun fact, tapeworms can cause bleeding in your intestines, and that can lead to infection.

Baby Food Diet

Baby food jars for weight loss

What it is: You eat 14 jars of baby food throughout the day. You can add in one meal of lean protein and veggies if you want.

Why people try it: It requires virtually no prep, is convenient on-the-go, and controls your portions. People try it for—what else—weight loss.

The reality: “Jars of baby food typically range from 30 to 100 calories each,” says Amidor. “If you choose to eat baby food all day for every meal, you may start feeling deprived of the variety of textures from a full meal,” Amidor explains. The flavor is also super bland and could lead to binge eating. As for weight loss? “It depends on the calories in versus calories out and also activity/exercise you do. You will, however, be able to find organic baby food and many are gluten-free.” So, you know, there’s that.

A Healthier Way to Lose Weight

Our consensus? Ditch the extreme diets and opt for long-lasting, sustainable weight loss instead.

“When you lose weight, you want to focus mainly on fat loss and preserving muscle mass,” says Caspero. The above extreme diets mainly result in the loss of water weight, and you’ll likely regain it when you stop the diet.

Her recommendation instead? Stick to a whole foods-based diet with lots of fruits and veggies, lean protein, healthy fats, and some whole grains. Be sure to eat enough, as well. Caspero says most women need between 1,400 and 1,600 calories a day. Throw in some moderate exercise, and you’ll see sustainable results.

And if you need an extra boost for good measure, try these metabolism-boosting foods.

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