What You Should Know Before You Try That Trendy Diet

A juice cleanse is one type of fad diet that sounds —and is — too good to be true.
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When it seems like everyone is losing weight and feeling healthier with the latest diet craze, it's hard to not jump on the bandwagon. But how do you know if it's a real solution or just a passing fad that might do more harm than good?

"It can be challenging to spot the difference between a fad diet and a legit one, especially at the height of its popularity," Maggie Moon, RD, a Los Angeles-based dietitian and author, tells LIVESTRONG.com.

Whether it's low-carb, low-fat, all bananas or no grains, a fad diet is often restrictive and makes promises it can't keep.

Learn what to look for when it comes to trendy weight-loss plans — and which to avoid altogether.

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How to Spot a Fad Diet

If it promises quick weight loss in a seemingly gimmicky way, chances are you're looking at a fad diet. These trendy eating plans usually develop a cult-like following quickly, which often retreats just as quickly, in search of the next latest and greatest weight-loss method.

There are a few telltale signs that a diet is nothing more than an empty promise, Moon says. These red flags include:

1. An Entire Food Group Is Eliminated

The Atkins diet, named after cardiologist Robert Atkins, took the concept of a high-protein, low-carb eating approach to another level, with a complicated four-phase plan that starts off with very few total carbohydrates (including those from fruits and vegetables), but no cap on saturated fat. (It does, however, limit added sugars and refined grains, which is in line with the 2015-2020 Dietary Guidelines for Americans.)

The severe restrictions on carbs, though, "furthers the misconception that carbohydrates promote weight gain and advocates a prolonged state of ketosis, which can be both unsustainable and harmful for long-term health," Denine Marie, RDN, Barcelona, Spain-based founder of Health Out of Habit, tells LIVESTRONG.com.

Although short-term weight loss is likely on the Atkins diet, your heart health, general nutrition and sanity are better served by a less restrictive diet plan, Marie says.

2. Results Sound Too Good to Be True

The Master Cleanse is a good example in this category, says Moon. The diet of hot water mixed with lemon juice, maple syrup and cayenne pepper claims to help you lose weight and cleanse your body of toxins, restoring you to optimum health.

And this one has some star power behind it: It's the diet that Beyonce reportedly used to drop weight for her role in ​Dreamgirls​, a film in which she played an underweight singer with drug-abuse issues.

But, according to Marie, juice cleanses like this aren't all they're cracked up to be. "They are not necessary to 'detox' your body or promote health," Marie explains. "Your kidneys and liver naturally detoxify your body, so focus on eating nourishing foods regularly rather than using juice cleanses to compensate for inconsistent or poor eating habits."

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3. The Program Relies on Selling Expensive Supplements

There are no magic pills when it comes to weight loss, Moon says. Period.

Diet pills promising lightning-fast weight loss became popular in the 1980s. But many of these appetite-suppressants contained phenylpropanolamine (PPA), which was later linked to stroke in young women.

The U.S. Food & Drug Administration (FDA) removed PPA from all drug products in 2000, thankfully. But keep this in mind: The FDA does not ensure the safety of any dietary supplements before they go to market.

"My recommendation is to focus on making healthy choices a part of daily habits," Moon says. "It's not as sexy as a magic pill, sure, but it's much more effective (and sane) in the long run."

4. The Diet Severely Restricts Calories

According to the Mayo Clinic, a safe rate of weight loss is 1 to 2 pounds per week, which means cutting out a max of 1,000 calories per day.

Very-low-calorie diets, like the cabbage soup diet — which encouraged followers to eat only cabbage soup for seven to 10 days and was popular with brides-to-be in the 1960s — are not realistic for long-term weight management. "While the weight may come off quickly, it won't stay off," Mandy Enright, RDN, the New Jersey-based creator of the couples' nutrition blog and podcast Nutrition Nuptials, tells LIVESTRONG.com.

Not only that, but the general lack of protein and calories in these diets can lead to fatigue, light-headedness and gastrointestinal symptoms, Enright says. And severely restrictive diets can be particularly dangerous for people who have certain medical conditions or are taking prescription medications.

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What's Wrong With Fads?

Fad diets may help you lose weight quickly, but that weight is just as quick to return once you go back to your old eating habits. In fact, according to the Centers for Disease Control and Prevention, research shows that people who lose weight gradually and steadily (about 1 to 2 pounds per week) are the most successful at keeping it off.

Why? These diets generally fail to teach you good, sustainable eating habits for the long-term. That's why one-third of all weight lost with a diet is regained within one year, and most is regained within three to five years, according to the American Council on Exercise.

Plus, fad diets are often nutritionally lacking, especially those that cut out an entire food group or groups. Instead of following a balanced diet, you follow a highly restrictive one that can be hard to adhere to for any length of time. If you fall off the diet wagon, which is almost inevitable when you're so restricted, you may feel like a failure and that a healthy weight is not within your reach.

And the kicker: Many fad diets don't encourage exercise, which is an essential element to any healthy lifestyle, says Mark Hyman, MD, family physician, author and director of the Cleveland Clinic Center for Functional Medicine.

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A Healthier Approach

Losing weight requires effort and commitment. Any diet that tells you otherwise will be gone tomorrow, replaced with the next best thing.

According to the American Heart Association, the best way to lose weight is with a portion-controlled diet that emphasizes fresh vegetables, fruits, whole grains, nuts and legumes, skinless poultry, fish and low-fat dairy along with regular physical activity.

Dr. Hyman agrees that avoiding processed foods, particularly those containing added refined sugars and flours (think: packaged snack foods and desserts), and emphasizing quality, whole foods instead leads to a healthier weight and body.

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